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FAQs about Holes, Drilling for Plumbing Marine Systems 4

Related Articles: Plumbing Marine Systems by Bob Fenner, Myth of the One Inch Beast (Why Relying on One Inch Overflows... or Overflow! Is foolhardy) by Scott Vallembois, Plumbing Return Manifolds, Refugiums,

Related FAQs: Holes & Drilling 1, Holes & Drilling 2, Holes & Drilling 3, & FAQs on: Rationale/Use, Designs, Fittings, Sizing/Number/Placement, Tools & Processes Themselves, Related Plumbing, Troubleshooting/Repair... Marine Plumbing 1, Marine Plumbing 2, Marine Plumbing 3, Marine Plumbing 4, Marine Plumbing 5, Marine Plumbing 6, Marine Plumbing 7, Plumbing 8, Plumbing 9, Plumbing 10, Plumbing 11, Plumbing 12, Plumbing 13, Plumbing 14, Plumbing 15, Plumbing 16, Plumbing 17, Make Up Water Systems, Pumps, Aeration, Circulation, Sumps, Refugiums, Gear Selection for Circulation, Pump Problems, Fish-Only Marine Set-ups, Fish-Only Marine Systems 2, FOWLR/Fish and Invertebrate Systems, Reef Systems, Coldwater Systems, Small Systems, Large Systems, Water Changes, Surge Devices,

Tank origins; tempered glass? /Drilling        12/2/15
Hello all!
I've been out of the saltwater hobby for many years. I was just gifted a new-to-me 200 gallon glass aquarium that I'd like to set up as a reef tank.
I'm searching for the origins of the tank to see if it's tempered glass, as the first thing I want to do (need to decide) is drill it to accommodate for a coast to coast overflow-after checking to make sure it's not a leaker;)
There is a small sticker attached to the inside rim with the logo of a small anchor, the number '2' and what I'm assuming is a born date of Nov. 22, 1985. Are any of you aware of what brand that would be, and if the sides are tempered? I've Google searched to no avail -
Thank you so much!!!
Ginger New
(Yeah, I know...the 80's called and they want my email back)
<I think this is an Atlas aquarium.... most all commercial glass aquariums (production) were/are made of non-tempered glass; the few that were, only the bottoms were tempered. There are ways of detecting temper....
Bob Fenner>

<Ahh, now see the "Anchor" on the label.... this is an Oceanic; and the bottom IS likely tempered. I would NOT drill the bottom pane.

Drilling a tank. 10/17/10
Hello crew- I have a 125 gallon marine aquarium. I want to have this drilled instead of
using overflow boxes. I am not sure of drilling this, as I don't want it to crack. I know there are no guarantees. My local fish store said they would drill it for $20.00 per hole. (no guarantee on cracking). My question for you is- how to do this properly. What size hole, how many and how far down would you put them? ( I have two tidepool 2 filters for my sumps.)
<Easily enough done... read here: http://wetwebmedia.com/pbholestools.htm
and the linked files above. Bob Fenner>

350G 48" diameter, 48" tall, 3/4" inch thick acrylic tank with 8" square center overflow that's in need of some love. 7/21/10
<Hello there Rob>
I have just bought home a used 48" diameter, 48" tall, 3/4" cylindrical acrylic tank with 8" square center overflow that's in need of some love.
It has a large decorative coral center that looks to be epoxy or resin in "aged" condition. See pictures below.
<None there>
I plan to cut the top acrylic spar that runs across the top of the overflow so that I can remove the decorative coral to refurbish it and make it easier to drill holes in the bottom of the tank to re-plumb it for better circulation. I was going to use a Tenryu blade (#PC-18560CB)
<A plastics/acrylic blade... this will work>
with a 15 Amp Framing saw and a clamped angle iron guide- and then have a new 1.25" Acrylic spar machined and beveled to overlap the outer rip and 1" solid acrylic pins to keep it in place.
<Nah... if you're sure this is a one-time do, just solvent the new overlapping brace atop the partial olde>
I dont know yet if the coral is bonded to the acrylic bottom, but I guess I'm going to find out.
<Almost assuredly it is not bonded... such constructs, particularly in these settings, are after-market, other-manufacturer "drop ins". Should lift straight out in one piece if not too "gunked in" currently>
I also planned on using a Starret brazed diamond hole saw to cut sixteen (yes, 16) 2" holes in the bottom of the tank for a closed loop recirculator.
<Mmm, I definitely would NOT do this. closed loop recirculation is really olde hat, not efficient, noisy... Instead look into internal magnetic drive motorized pumps like Tunze, Eco-Tech et al. Read here re:
the third tray down>
The intricate decorative coral is going to be a PITA to clean of detritus,
<Nah... take it out, soak it in a mild bleach solution... See WWM re...>
so I want good slow moving turbulent motion with no dead spots. To re-inforce the bottom of the tank, I was trying to figure out how to sandwich solvent weld a 1/4" Acrylic sheet cut to a 48" circle.
<You can/could "weep" one of Weld-On's lower viscosity solvents through all those cut outs, but I would not drill through the bottom as you propose above. IF there are returns and overflow/s that are already in place in the
center 8" square, use these to plumb all underneath. In other words, don't drill more openings!>
The holes would penetrate both layers and the whole thing would sit on plywood on the existing circular steel framed base. The original setup had the bulkhead nuts on the back of the ply, rather than overdrilling the ply with the nut on the back of the acrylic.
<This is a mistake that I definitely would correct here/now>
Based on the badly corroded steel stand frame and ply scrape marks, I think they must have had leaks. I'd hate to have 16 leaks plus the 6 holes that are already in the tank bottom. In the event of a major earthquake, I am thinking that schedule 80 tank bulkheads aren't going to keep the tank on the stand anyway.
<IF the ground moves this much, the sch. 80 fittings will be a small worry>
I want to avoid an internal bottom manifold with fewer holes - unless you can find someone with 4 foot arms that can adjust/fix them later as needed.
<Ah, no>
The overhung coral makes it near impossible to work on the bottom of the tank after the water is in and the tank top is 7.5 feet in the air.
<Ladder and tools, possibly a friend to guide you>
As I contemplate doing this, I remembered that if I write off this tank, my 3 and 4 year old kids will likely lose respect for their Father, which could lead to a substantial long term psychiatric bill in later life.
<Lo dudo>
And then there's the punitive wife damages that I don't care to think about after the icy stares she gave me for showing up with this tank on the back of a trailer unannounced - "hey honey, if I'd discussed this with you first, you would have said 'no', so why say anything?".
<You're treading on very thin ice here for sure>
For my children's sake, can you give me some advice?
Thanks a bunch,
<Make it known if you'd like more input, rationale re my position here. Have you watch friend Jim Stime's LA Fish Guy video... on you tube, re such a tanks install, operation? You'd do well to do so. Bob Fenner>
Re: 350G 48" diameter, 48" tall, 3/4" inch thick acrylic tank with 8" square center overflow that's in need of some love. 7/21/10
Thanks Bob. Having looked at Jim on YouTube, I think he's my neighbor. Not kidding, I live in Westlake Village, Thousand Oaks, CA.
With regard to a ladder and a friend, I've attached a picture which I think best describes how your procedure would translate to this tank.
<I see the bottom pic>
The opening on each side is 12" wide at it's widest point one way and 24" in the other.
I take back the "best describes" bit. Please mentally substitute a small malnourished boy for Houdini.
<Maybe two, one for me, t'other for you>
So let's imagine for a moment that I had in my possession four low power/noise 1750 RPM Reeflo and Dolphin AmpMaster pumps for filter return and recirculation, a high speed pneumatic valve actuator (AKA wavemaker)
together with a subfloor cavity close to the slab that the tank is going on that could house all said noisy equipment with adequate ventilation, cold & hot water, drainage, electrical supply and physical access for maintenance.
<I still wouldn't drill the bottom>
In such a circumstance, I might be really tempted, at least conceptually, to drill (and reinforce if necessary) the bottom of the tank and have nothing with moving parts in the display tank.
<Mmm, moving parts aren't really such a big deal... I do wish you had another 1.5" hole for running electrical conduits from inside and above (lights) the tank down through>
Hypothetically speaking, from an engineering perspective, how would a competent fabricator do this? Then, same question, only for a software engineer pretending to be a competent fabricator.
<Do... what Rob? Again... one recirculating pump outside... of good size if you want... up to a 1.5" ID discharge!>
I've included a scale drawing of the tank bottom that shows the overflow box in yellow, the existing holes in white and the proposed new holes for the wavemaker pipes in red and orange.
I'm OK, with heck no - just need to understand the reasoning behind what the risk/barrier is to drilling the tank ... other than "people don't do that" or "are you nuts?".
<The chances of leaks, breakage, and just the lack of benefit from making more holes is simply overwhelming. I am also a long-time content provider in the dive (as in scuba) travel interest... and have had my experiences with through-hulls on boats/ships... the less the better is my rule>
I'm also OK with "Jim charges $80/hour, quit bugging me and call him to come over so he can tell me in person that I am nuts".
<Heeeee! Do say hi to him for me>
Thanks again for humoring me.[image: Aquarium Holes.jpg]
<Be chatting further I hope/trust. BobF>

2.25" hole in the middle, all others 1.5" ID, 8 in' square overflow box in the middle

Drilling for a 120G 5/25/09
I'd appreciate your opinions on this drilling plan (see attached image) for the back pane of a 120 gallon glass tank (48L x 24H). The four holes along the top edge are for two 2" bulkheads for a drain to the sump and two 1" bulkheads for the sump return.
The other 2" bulkheads in the bottom corners would be for a closed loop. The remaining four 1" bulkheads would be capped for now and used for adding things in the future like some extra closed loops. Is this too many holes for this size the size of the glass panel?
<No, this is a fairly thick, strong panel.>
If so, which ones would you leave out or downsize?
<None, I am a fan of drilling what you want and may want before setup!>
How would you adjust the placement of the holes?
<I would not.>
Can I pump 2000-3000 GPH or even more through the 2" closed loop?
Do you recommend a specific tank manufacturer who would do the drilling for me while the tank is being built?
<Most all will, but I have found Aqueon very easy to work with.>
I am leaning toward Aqueon or Oceanic but really don't have any experience buying drilled tanks.
Thanks for your comments!
<Welcome, Scott V.>

Drilling a Odell fish tank? 10/9/08 Hi, I have a 55 gal O-dell fish tank. With marble (plastic) trim. I also have a 30 gal sump I made for a reef tank. I do not have much faith in siphon overflows. <Nor do I!> I was wanting to drill the top of the back glass and make my own overflow that way. What I do not know is the glass tempered on the back wall. I have looked up O-dell fish tanks on many search engines. All I seem to find is this site ( witch has good info by the way). The tank dims are about 48'' X 13'' X 20''. Hope you can help. <I can't offer any information on this specific tank. From my experience drilling I can tell you that there are quite a few tempered 55 gallon tanks out there. Your best bet will be taking it to a glass shop to find out if it is tempered or to do a little test yourself. You can take two polarized filters, stack one on top of the other. As you rotate the top one you will see how it fades from light to dark. Try this on a now non-tempered panel, with the glass sandwiched between the filters and you get the same effect. Do this on a tempered piece of glass and you will see a fairly distinct pattern much different than the non-tempered. Have fun with this, drilling is very much worth this extra trouble, Scott V.> <<RMF will chime in here... if memory serves... this fine line of all-glass aquariums did have a run of some of the larger sizes (e.g. 55s and up) that the bottoms were at least sometimes made of tempered glass. As far as I recall however, the rest of the panels were not. I STRONGLY suggest you follow ScottV's advice here though and do the simple test mentioned.>>

Re: Drilling a Odell fish tank? 10/10/08 Will do but I have never heard of polarized filters. Sure I can Google something on that. <Google will find you some fairly quick. Polarized filters can be found in the camera world as lens attachments. For your one time need here I would go down to the local Xmart and buy a cheap pair of polarized sunglasses. Pop the lenses out and you have your filters. Scott V.>

Drilling Fish Tank 01/09/2008 Hello All <<Hello, Andrew here>> I have attached pictures of the tank I started building. Its an all glass tank , however I would like to include a sump filter. The problem is that their are no holes drilled. Would I be able to drill holes with the tank already build or is this a bit risky?. Are there any alternatives that you could suggest? <<As long as the tank glass is not tempered, it should be fine to drill. Other alternatives are by using an overflow box>> I was also thinking of putting in three cross pieces on the top of the tank for braces. Do you think this would be sufficient with regards to strengthening the tank. I have used 12mm glass for the bottom, front and back and 10mm for the sides. <<If its over 30 gallons, then at least a 6 inch wide centre brace is a must have. Brace should be made from the same thickness of glass as the front, back and sides>> <<Thanks for the questions, A Nixon>>

Acrylic aquarium 11/6/06 Hi, I'm entirely new to this hobby, (lifestyle). I've been reading and reading and reading. <Good> I'm interested in getting an acrylic tank, 48x18x20. I'm not going to get it reef ready, but I will be drilling the back of the tank for a Calfo overflow. I'm getting different opinions on whether I can attach an acrylic interior overflow box to the back of my tank. <Mmm, you can... but if you're at all unsure of your skills at such a fashioning, attachment, I encourage you to secure this to the inside> If so what do you recommend as a good solvent to do so. <Weldon... number... 40> Will I have to worry about any bowing that would break the integrity of the attachment. <Mmm, no... not if the structure/weir is cut to be flush/parallel with the wall... and solvented all the way around... perhaps a practice go outside the tank...> Thanks for all your help. You have the best and most informative site that I've found. Joe <Thank you Joe, and welcome to our ever-wonderful hobby. Bob Fenner>

Re: Tank re-drill Aloha <And to you> Thank you so much for the advice. I actually just finished figuring everything out without having to redrill the tank (I simply don't have the space in my overflow for the flange on a bulkhead that size). <Mmm, could just come over the side/top> I guess I was a little too excited to wait since Am nearly on the verge of having my tank set up again( its been way too long). I figured I would at least email you and tell you what I did to make it work. <I stated the easy options...> Never know I might have done something right that others could read this time. What I did was really just a few small modifications. To handle all of the 2400gph of overflow I used my return holes which are also in my overflows) to be Durso style drains as well. So I now have two 1.5" drains and two 1" drains. I rerouted my return up behind the tank to get to the return holes on the tanks top. My returns were only 1" so they didn't give me a huge amount of extra overflow but every little bit counts. <Yes> I also did lower my standpipes. Upon better inspection I found they couldn't have been more than an inch under water level. <Very common... and safe/r should the power/pump fail... in terms of transit volume... and a rate-limiting factor for sure... many folks seem to have some notion that somehow water is magically "sucked out" once reaching the level of such overflows.> They are now at three inches below. I also tore out all the plumbing underneath the tank. All those elbows and other fittings I figured were slowing flow down. I instead replaced all of them with flexible pvc pipe. As for the aspiration of the drain lines...(I don't know if this helped but I did it anyway) <Does help. Both for flow increase and noise reduction> I installed small tubes at the tops of the stand pipes going down almost to the bulkhead and at the end of the drain lines both submerged outputs now have small 3/8th holes just above water level to let out a little more air. Worked like a charm. Am betting the two extra 1" drains along with the flex pvc for better flow had the most to do with its success. It handles the pumps output now no problem. Of course, 2" overflows would have been much better but it is a little bit of trouble taking a 240 gallon tank down to the shop and there always the fact that they wont fit. So once again I really appreciate the advice you gave me and hope you at least get some good diving in while in Thailand. Tank care! -Chris Mahalo nui loa <Thank you for this follow-up and report of your success. Terima kasih. BobF> Using Old Rock/Drilling Bulkheads - 08/27/06 Hey guys, <<Hello (but don't forget the very capable ladies here as well)>> Thanks again for your time and dedication to our hobby! <<Is an honor/pleasure to help>> I have 2 issues I need help with: <<Alrighty>> First, I have read thru the LR section in depth and could not find an exact match to my problem. I recently purchased a used, and neglected 120 gallon that housed a single clown grouper with several large pieces of rock (it was a FO with rock??). <<Indeed...that would be a FOWLR (Fish Only With Live Rock)>> I have kept the rock wet for a few days and can see a few small life forms on it (actual moving little white/clear bug things). <<Amphipods...probably>> The rock looks terrible as the tank was neglected and the rock is all dark brown and black. I will be setting this tank up as a FOWLR and I am thinking that I would like to start over with the rock. Letting it dry and cleaning it somehow and then letting it cure in the tank for a month or two before adding new fish (pending testing results). <<Mmm...letting the rock "dry out" will negate its benefits...why not simply keep the rock as it is? If the color is an issue, it will likely change with improved water quality/lighting>> Can I get the rock to look better? <<Depends on what you consider is "better">> Is it worth losing whatever life it has on it? <<Not in my opinion>> It was not really a traditional live rock, <<...???>> it has life but it looks very bad. They are great sized pieces. The substrate is crushed coral, I would like to reuse it. It also has black and brown staining on it. <<This is most likely forms of algae, and will "change" with changes to the environment, as stated>> Can this also be cleaned? If so how? <<Swirling/rinsing with clean saltwater will do the least damage, though you will still loose some biota>> I don't mind starting over on the rock but will my cleaning methods effect any future fish or possible changes to inverts/coral down the road if I go that direction? <<Indeed it will...you could give the rock a rinse and a "light" brushing with a soft-bristle brush, or replace it (entirely or in portions) with fresh live rock>> Second, the tank is a traditional (non RR) tank. It came with a sump/wet-dry and a HOT overflow. I am weary of the overflow as I hear that they will eventually fail. <<Is a good chance, yes...but this risk can be lessened a great deal by employing a redundant system (two siphon overflow boxes) with the first>> I have once again read on WWM about tank drilling and am thoroughly confused by all the different opinions and issues. <<Let's see if I can help un-confuse you>> I would like to drill the rear for 2 sump supplies and 2 sump returns. Where exactly (how far down and over/apart) do you recommend? <<Well, if you've established the back glass in non-tempered, I recommend you place the throughputs the width of the hole-to-be-drilled from the edges of the tank, and no closer re to any other throughputs...clear as mud? For example...a heavy duty 1.5" bulkhead requires a 2.6" hole...the edge of the hole should be no closer than 2.6" from any edge of the tank, or from any edge of another bulkhead hole. Adjustment of water height in the tank can be accomplished with elbows to raise the level of the pipe outside the tank, or used as adjustable "overflows" within the tank>> Also what size is best for this size tank if I use a strainer for the supplies down and a directional elbow for the return up? <<Two 1.5" bulkheads for the drains, and one or two .75" or 1" bulkheads for the returns...or you can simply plumb the returns over the back/ends of the tank>> Should both the supply and the return have a T installed before the sump? <<For what purpose?...in what configuration?>> Also, are there and tips for drilling? <<Indeed, yes...have a read here: http://www.wetwebmedia.com/pbholesfaqs.htm >> I have seen a tank drilled before and they used cooking oil for the lubricant while cutting? Is this OK? <<I've always just used water for lubricating the drill bit...works well and is easy to clean up>> I plan on ordering the needed bits online, any recommended sources? <<Several choices about...I bought my last bit here: http://www.diamond-drill-bit-and-tool.com/Diamond-Drill/MAIN.htm >> Any tips? <<Heat is your enemy...follow the recommended rotation speed for the size core drill bit used. The manufacturer states these bits can be used "dry", but use of a lubricant (water) will keep heat down, greatly extend the life of the bit, and speed the drilling process...I use simple 'Play-Dough' to create a "damn" around the area to be drilled and fill/refill with water as needed while drilling. Also, when possible, use of a drill-press or drill-jig to keep the bit vertical to the glass surface will lessen the chance of damage/fracture of the panel>> Thanks once again for your help and contribution to our obsession!!! Randy <<Quite welcome. Regards, EricR>>

Oceanic Reef Ready...Bulkhead Hole Size Problem?? Something awry with this resp. 8/3/06 I ordered a 215G oceanic reef ready aquarium, which was delivered about a week ago. I was just starting to put things together when I noticed that both the drain and return holes were drilled at 1 3/4" one each of the two overflows. From the overflow kits provided, it seems to me as though the return hole should have been drilled smaller, as the bulkhead for the return line is only 3/4" compared to the 1" drain bulkhead. I did not order any custom drilling on this tank. Do you think a mistake was made here, or would it be reasonable to place a 3/4" bulkhead into a 1 3/4" hole? If this was a mistake, is there any problems, such as noise issues, with using a return line the same size as the drain line? I'd appreciate any available advice and suggestions, I'm really at a loss here. <Kevin, I suggest you contact Oceanic on your question, being a warranty is involved here. You may have a problem, as most 3/4 in bulkhead fittings require a 1 7/16 to 1 1/2" hole in the tank. <<? RMF... usually 1" O.D.>> I'd see what their reasoning was in this regard. James (Salty Dog)> Kevin

Re: Oceanic Reef Ready...Bulkhead Hole Size Problem?? 8/4/06 Hey James- <Kevin> Thanks for your reply. <More than welcome.> I did contact Oceanic after having sent this question to WWM. There response was that on the larger aquariums, they drill 1 3/4" holes for both the drain and returns. I guess I need to take their word for it, how can I say they don't? <Agreed.> But I'm not comfortable fitting the 3/4" bulkhead, supplied in there <their> overflow kit, into a 1 3/4" hole, even though it may work if it were fitted precisely. <Have you asked them about this?> Do you see anything wrong with using 1" bulkheads for both the drain and the return, and then reducing the drainpipe down to 3/4" for the return after the bulkhead (within the overflow), so I can still use the supplied 3/4" end fittings for dispersing the water back to the tank? No problem here, very common practice in this regard.> Oceanic told me this would work out fine, but then, I would imagine that they don't want to have this tank returned! Would this cause me any potential problems that come to mind? <No, just use the larger bulkhead and reduce as you mentioned. I erred in mentioning the 3/4 bulkhead would require a 1 7/16 minimum hole size. I believe, although it was not mentioned, that this bulkhead was a schedule 80 unit with a much thicker wall.> Thanks, <You're welcome. James (Salty Dog)> Kevin Re: Bulkhead fitting 8/4/06 Bob, Checked several sites on this. Here is one example. 3/4" Dbl Threaded Bulkhead (Rainbow) You Pay: $ 4.29 In Stock: Yes * Item Number: RL0183 This bulkhead requires a 1 7/16" - 1 1/2" diameter hole. <... very strange James... I/we sold and installed thousands of these... of PVC and CPVC construction... they will fit a 1 1/4" hole... and not much larger... Perhaps you're thinking of a schedule 80 (for whatever reason someone would pay for such... rated fro 800 PSI...) fitting? A bit "thicker" in the throat> For proper seal, the gasket must go between bulkhead flange and tank wall. <Best to use two gaskets... one in, one out... both with a light smear of 100% Silastic on both sides... BobF> Regards, James

Re: Bulkhead fitting 8/4/06 Thanks, Bob Could very well have been 80, but didn't search for such. Would you have a link to a distributor handling schedule 40 PVC/CPVC? Thanks, James <Is what most everyone handles... Made by Spears, Dura... sold by All Seas, likely Marine Depot... BobF>

A little freaked out ... drilled glass tank worries/worrier 7/26/06 Hello Crew, well to the point.... I'm literally days away from setting up my new 180, beautiful stand/canopy done, Lifereef sump/skimmer, 6 *80W T5 with 2 * 250 MH HQI retro, etc etc etc. I got great stuff and took my time buying and planning, reading and asked lots of questions (a few here).. Well I'm just about ready to go and I was on Reef Central tonight only to see a picture of a 180 show like mine that cracked on the bottom that was drilled!!! It has freaked me out a bit. My tank was built by a local guy with 1/2 inch glass, I got All-Glass to send me their braces for the top and bottom and siliconed in custom built acrylic overflows. The bottom pane has 8 holes in it. 2 in each overflow and 4 in the corners for Oceans Motions device. The tank I saw on RC cracked because his holes were in the middle from the weight of the rock. So I would like some reassurance or some pointers 1) Is this not safe? <Should be fine> 2) I plan on a 4" DSB with 200 lbs of live rock so you have idea of weight. 3) Can I support it better to be more strong along with the All-Glass brace? Maybe Styrofoam or something. <A good idea to assure the tank itself is on a support that is complete, strong, level and planar... Have you read here: http://wetwebmedia.com/aqstands.htm and the linked files above?> I can provide pics if needed, the stand is solid and custom designed buy a contractor experienced in aquatic design and is lipped so the bottom of the tank slides nice about 1" inside. Hopefully I am OK here and you calm me, but better safe then sorry. Thanks Jeff <Likely all will work out here. Bob Fenner>

Need increased drainage flow to keep up with pump... Small holes really don't 7/7/06 Hi, I just started plumbing a 75g reef-ready tank with a corner overflow and 1" bulkheads drilled on the bottom of the tank. <... need to be bigger, larger diameter...> The filter I plan on setting up with this tank will be a EcoSystem mud-filter which requires 800 gph to run effectively for a 75g aquarium. <Mmm, could/can be run on less... with other filtration, circulation provided otherwise> The pump I bought is a CA-4000 submersible pump which puts out over 1100 gph at 0' of head and around 800 gph at 3 1/2' of head which is how I have it connected currently. My problem is that the overflow drain cannot keep up with the pump and the pump begins to pump half air half water after only a few minute of the system being turned on. <Yep> I've researched and found that the max flow through a 1" bulkhead is around 600 gph so most likely that is my problem. <Agreed> Is there any way to increase the drainage flow without drilling a larger hole for a larger bulkhead? <...? Mmm... well, no... you need to either add flow elsewise or re-drill... Please read here: http://www.wetwebmedia.com/pbholesfaqs.htm and the linked files above. Bob Fenner>

Set Up/Sump/Drain Size - 03/12/2006 Hi....<Hello Mike.> Thanks for your time. Fantastic web site. "Before" doing my homework I bought an all-glass 54 gallon corner tank. I thought that the 1 1'4" predrilled drain would be enough for this tank draining about 600gph but after reading the fine print I found out that in the corner tanks the flow is only 400gph. I'm considering using the predrilled 3/4" return hole as another drain and plumbing the return over the top of the tank. I'm just not sure if the two different sized drains will be a problem and if the skimmer box will be able to handle this additional flow of water without backing up. Any quick thoughts would be appreciated. <Mike, the 1 1/4 drain is more than enough for a 600 gph flow. Don't know where the "fine print" came from. James (Salty Dog)> <<James, after the diameter of the bulkhead is considered, the inside diameter of this through-put will likely be less than an inch... RMF>> Thanks for your time <You're welcome.> Mike

Re: Set Up/Sump/Drain Size - 03/12/2006 - 03/13/2006 Are you sure, Bob? Seems like all the bulkhead fittings I've used will allow the entire ID of the pipe to be of use, that is once you slip the PVC pipe in, and look into it, you cannot see any restrictions caused by the bulkhead fitting, that is, the lip on the bulkhead is the same size as the thickness of the pipe. In using the drain size calculator, for a 600gph flow rate, a minimum pipe diameter would be 1.01 inches. The results do not specify ID size so I'm assuming it is the actual pipe diameter which is how pipe is measured anyway (I'm sure you know). A 1 1/4 pipe has a ID of 1 1/4 inches. If you believe I am wrong...my apologies. James <Am pretty sure the writer is referring to the OD of the hole cut in the tank... the throat of the bulkhead takes up space/diameter. B>

Plumbing Insufficient Throughputs - 03/09/06 Hello all! <<Hi Kristen!>> Thanks for the great work. I am now on to the task of plumbing my AGA 72 gal bow with the horribly insufficient overflow. <<Mmm, yes...>> It has the standard two holes. one to drain, one to return. <<And both too small...>> Not enough to do different types of corals (hubby is still determining his wish list). So I am considering some other options for getting more flow without drilling more holes in my tank. I have some thoughts...tell me which you would choose or add one of your own. <<Gladly!>> 1) Current system has the drain going down to a 3 section sump and returning w/what will be a Mag 9.5 (gate valve needed here). <<Indeed! That single 1" drain is going to limit you (practically speaking) to about 300-350 gallons per hour.>> Overflow is 1" and return is 3/4". The return y's at the top and has 2 loc lines. one going to the front of the tank and one to the back. I could keep this as is and add a closed loop system similar to Melev's 29 gallon (not sure if I would go with the pump in the tank or out of the tank yet though) <<Don't think I care for this.>> 2) Make both holes in the overflow area drain holes. <<This is what many folks do.>> In this configuration I could either drain both right into the sump with one return via a manifold or make one flow into the sump and one into a closed loop system. I haven't really seen this mentioned on your website but I have not read every single page. <<Quite do-able>> I also haven't sat down and figured out what my flow would be...I suppose if it's still not enough flow it's sort of pointless to do this. <<Hmm...the closed-loop on the 3/4" drain would use/require a pump with the same size intake...this will indeed limit choices/flow.>> 3) Just keep as is and use powerheads (said with a sigh and head hanging because we are having so much fun with PVC). Thanks in advance for your sage advice! Kristen <<Well Kristen, given the choices you've outlined I would go with option #2 with some minor modifications. If I may... I would drain the 1" bulkhead to the sump and return this to the tank, over the back, with a smaller pump (Mag5/7 depending on head height, plumbing angles, etc.) and/or gate-valve striving for a flow rate of about 300-350 gph. I would then plumb the 3/4" bulkhead as a closed-loop (not through the sump!) using the Mag9.5 pump you already have. With any luck, this will give you an overall flow rate of around 10x-12x the tank's total volume. Regards, EricR>> Plumbing Insufficient Throughputs II - 03/09/06 One quick question...would I eliminate my need for all of this by getting the Wave 2k? <<This is another alternative, yes.>> I am seriously considering this and will be putting a call to them regarding rock placement in reference to the placement of the machine. Just another thought. Thanks again for your response!! <<Welcome, EricR>>

Drilling holes in non-tempered upper back wall of tank 2/17/06 Building a tank 72" x 30" x 30" glass only with 1/2" glass. I am planning on 5 holes 2 3/8" for 1.5" bulkheads <... don't need to be this diameter... for Schedule 40 through-hulls two inch ID will do> spaced evenly across the top back tank and likely 2 other holes 1" and 2" for two bulkheads half way down about 1/3rd in from each side on the back. <? for what purpose?> Tank will be Euro braced and likely center braced as well. All panels will be resting on top of the bottom plate. <Okay...> Will this many holes compromise the strength/integrity of the tank? <Possibly> Is 1/2" tempered glass strong/thick enough for the bottom plate? <I'd spend a bit more money and have a thicker bottom... and a bit more time in making my plans re plumbing/holes before drilling. See WWM re. Bob Fenner> Re: drilling holes in non-tempered upper back wall of tank 2/17/06 The hole diameter was for Marine Depot/Dr. Foster & Smith bulkheads per their specs. <... something is off here... Even Sch 80 (which you don't need... don't want, as the larger holes are more a problem with structural integrity) don't require such large holes. ... I'd look for Sch. 40 gas/jacket fittings as for spas and cut or have cut the smaller, 2" diameter holes> I intended to have 2-3 drains & 2 returns (might cap 1 for possible future flow increase). The other two holes midway down would be also intended for possible closed loop/addition flow at some future point (likely capped to begin with). <... I would not drill these... for structural and functional reasons... can/should be placed near/er the surface, just below the overflows height, but spaced away...> Planning on using sequence Reeflow dart for return pump from sump( will have skimmer, refugium in sump). <A good product, company. Bob Fenner>

Hole In The Bottom 2/14/06 Hello Crew, greetings from South Carolina! <Mmm, where's that EricR... practically a neighbor!> I've spent hours (if not days) plundering your very insightful composition of aquatic resources. I'm grateful for the opportunity to educate myself through such a beautifully constructed presentation of knowledge. <High praise indeed!> I have learned much, but still have some questions that require an answer. Tonight I will present you with just a few of these. I recently began plans for a 300 gallon aquarium (75" L x 39.5" W x 26" H). This aquarium will be built-in with three viewing sides ([75" X2] [39.5" x1]). It will replace a downstairs bathroom in my house which is centrally located between my living area, foyer, dining area, and kitchen. This spot will work perfectly b/c of the in floor drains, plumbing that currently supplies the sink and toilet, <Nice> and the powered vent in the ceiling of which all will be beneficial to this setup. The tank will be constructed of 3/8" untempered glass on four sides with four 6" wide 3/8" glass braces spaced evenly at the top (already acquired). The bottom will be 3/4" MDF fiberglassed with epoxy resin and having a 3/4" wide x 3/16" dado for the glass to "nest" in with silicon (already completed and pictured in attached jpeg). <I would go with glass here as well...> The tank will have 2" freeboard (a 24" column of water). <I see> Tonight's questions are oriented towards the method the overflow will exit the aquarium. I am interested in drilling in the bottom of the tank (MDF/Fiberglass) rather than having the glass drilled. A PVC pipe would pass through this hole to the correct height have a larger collection area at the top. Would this be something you recommend? <Could be done. I would buy enough "extra" gaskets (usually only get one to a set) to have one on both sides (in and out) and Silicone these with a smear on both sides for the bulkheads> Should this be avoided? <? No... if the bottom is supported sufficiently to prevent bowing...> If this is possible, what method would I use to secure the PVC to ensure a watertight seal (gasket and compression fitting or silicone)? <Bulkheads, through-hulls of Schedule 40 (or 80 if you want) should do fine here... with threaded nuts... the two gaskets...> Obviously this is a matter of concern for me and any advice concerning this matter would be greatly appreciated. Thanks, Gabriel Nix <Have your shop or a service company that does installs show you the few variations available here. The technology... tools and materials for effecting such through-puts is simple, straightforward... once you've had exposure. Cheers, Bob Fenner>

Back-Wall Plumbing? - 02/12/06 Guys I picked up this tank yesterday and now I am thinking maybe I shouldn't have, it wasn't plumbed with overflows but drains on the top corners. Is this a really bad way or can this work, should I try to recoup my losses and move on? Take a look, I went and took it off his hands cause I thought it would make a great behind the wall tank. What's your thoughts? (It's sitting backwards on the stand to see the plumbing in the back) <<The holes were drilled a bit close too the edges for my liking, but this is a perfectly viable method for plumbing a tank, and is gaining in popularity with folks who don't want "overflow boxes" visible/taking up space in the display. My own tank is plumbed similar to this, though my bulkheads are on the "ends" as I have an in-wall installation viewable from two sides. Regards, EricR >>

New 125 Gallon Setup II - 02/09/06 Dear WWM Crew (Eric) <<Hi Andrew>> Thanks for your reply. <<Very welcome>> Unfortunately, I am not going to be able to get a 125 gal. <<Bummer dude>> But the good news is that I am going to get a 90 gal. <<Cool!>> I contacted the supplier and found that it is the same deal. If drilled it comes with two 1" bulkheads and two 3/4" bulkheads (for returns). They also said that you cannot have them increase the size or number of bulkheads. <<Sheesh! I would consider looking to a different manufacturer.>> Quite disappointing! <<Agreed mate>> So I was leaning more towards buying a standard aquarium and having it drilled by a local glass shop. <<This (to me) is a better option than ordering a tank that you already know won't fit your needs.>> They can drill any number of holes and any size up to 4". But they also warned the more holes and the larger the holes the riskier it gets. <<Ok>> I was thinking of drilling two holes for the drainage into the sump. If I wanted roughly 1000 GPH of flow how large of bulkheads should I get? <<1000gph total? A pair of 1 1/2" bulkheads should handle this fine. You'll find flow calculators that will tell you two 1" bulkheads can do it, and yes, they would...but with much difficulty/fiddling/noise. Take my word and go with the larger bulkheads. I also want to mention, 1000gph through your sump is likely going to make a heck of a racket...do consider using one bulkhead for the sump return (300gph-500gph pump) and the other for a closed-loop (1000gph pump). Your decision...just a suggestion.>> Also, in your last e-mail when you responded: "I was thinking several layers of mesh. Would this be the proper type of setup to include the bio-balls or something similar? <<I would forego both of these and employ one or two fluidized-bed filters for additional bio-filtration and a canister filter for chemical/carbon filtration..." Did you mean forego the sump or just the bioballs and mesh? <<The latter. The mesh will be maintenance hassle, and the bio-balls (submerged) will be of little value (much better to add a few pounds of live rock).>> I could go without the sump but thought that the larger the volume of water the better. <<Indeed, do keep the sump.>> I didn't think the system could function optimally on a canister and a fluidized bed filter. <<Used in conjunction with the sump these will benefit a FO system greatly.>> Otherwise I am in the planning stages of the rest of the aquarium. Feel free to correct or add anything) <<There you go...giving me free rein again <grin>.>> I was thinking a thin layer of crushed coral for the bottom. <<1" or less...>> I already have roughly 40 lbs. of live rock and may get more. <<Excellent! Just don't forget to leave swimming room for the fishes...the 40lbs. may prove to be plenty.>> I was thinking of just a heavy duty plastic container for the sump (With some modifications for skimmer) mostly just to increase water volume. <<This is what many hobbyists do.>> But most of all, I have been thinking about and researching the inhabitants. <<That's good to hear.>> They are as follows: 1. Maroon Clownfish 2. One of the following: A. Blue Tang B. Yellow Tang C. White Cheek Tang D. Convict Tang <<'B' or 'D' are your only choices for this size tank, in my opinion.>> 3. Flame Angel 4. One of the following: A. Auriga Butterfly fish B. Teardrop Butterfly fish <<Both are very good choices as butterflies go...glad to see you did your research.>> 5. Maybe a few Damsels or other small schooling fish. Thanks in advance for wading through my jumbled thoughts and answering my questions. Best regards, Andrew <<Is my pleasure to assist Andrew. Regards, EricR>> Acrylic gluing... plugging holes. 1/22/06 Howdy folks, <Paul> quick question about my tank. I have two bulkheads in my 90 gallon reef tank that I don't want to use anymore. They are on the back of the tank, one near the top and the other near the bottom. Can I remove the bulkheads, then get two small squares of acrylic and use Weld-On glue to cover up the holes? <Yes> Will they hold once the tank is full? <Hopefully, yes> How big should the squares be? <An inch or more beyond the hole diameters> On the outside back, there will be the openings where the holes used to be. Should I add something on that side in case? <Could, but not necessary> Is there another way to close up the holes? One bulkhead is 1" threaded, the other is 3/4 non-threaded. Is there some sort of plug that could be put in there. <Yes... a piece of pipe in the non-threaded one with either a threaded or not terminus with a cap... the threaded one with a threaded cap, Silastic for "pipe dope"> What if I just cut the pipes (the ones coming from each bulkhead) from the back and cement them up with a PVC cap. <Could be done> I could leave strainers on the inside of the tank. It would be kind of a dead spot in terms of water movement (only an inch or two deep though), but nothing would get in there. What do you think? What would you do. Thank you very much Paul <If I was very sure I'd never want to re-use these through-puts I'd solvent the covers over, if not, cap them... Bob Fenner>

150 gallon reef ready tank... not ready aquarist 1/18/06 Hey guys I have a question I just picked up a used 150 gallon reef ready tank and it has 3 holes drilled in it and I wanted to know which ones were the intake and witch <With a broom?> was the outtake? <Mmmm> There is one in the center and the other two are in the corners( left and right). And also it looks like the two holes in the corners used to have the plexi glass boxes around them witch are now gone, where can I find new ones and do I even need them? <Good questions... answered on WWM... Depends on the size, the flow rate, circulation you want... it might turn out that you want all three as intakes for instance, and to return water over the top edge... Give the plumbing, et al. set up parts of WWM a read over cowboy, and we'll see you at the corral, yee hah! Bob Fenner>

Drilling acrylic 1/8/06 Hi, I bought a custom made acrylic tank that I plan to use as my refugium. I'm going to plumb it inline with one of the outputs from my overflows (~500gph). The tank is made to hold about 27 gallons (20Lx16Wx20T) and is made out of 3/8" acrylic. I plan to use a 1" bulkhead for the inlet and 1.25" bulkhead for the outlet. This will all gravity feed back into my sump and main pump. My question is can I use a typical drill with a hole saw bit for my bulkhead holes? <Yes> And do you have any advice for how to drill the holes? <Yes... Make sure the tool is clean, sharp... go slow... in/out a bit at a time to prevent binding... Some folks advise taping over the area.> Also, I'm going to put in a 5-6 deep sand bed of sugar sized aragonite and either Gracilaria sp. or Chaetomorpha. Does this seem ideal for my setup? <... yes. To the extent your plans have been detailed here.> My main tank is a 220g with live rock, a few corals, and a lot of planktivore feeding fish? <Don't know... do you? Bob Fenner> Thanks,

Horizontal overflows... cut fifteen times, measure eighty 11/22/05 Hi there, I was wondering if you could tell me who sells horizontal overflows? <Sells? Most folks make them... do you mean the parts for?> I tried to find some on the internet, but I couldn't locate any. A person I know is selling an acrylic tank and they have 3/4" holes drilled in it for a closed loop. The hole that I was considering using for the overflow is directly in the middle of the tank and about 10" from the surface. I am afraid that this might be too low for the horizontal overflow. <... me too> Is this a correct guess? <Ummm, uhh, don't be guessing here> Would I be better off to use the holes already there as a closed loop, and then have the tank drilled for the horizontal overflow? Thanks for the help. Brian <Need to read a bit more Bri: http://www.wetwebmedia.com/plumbingmarart.htm and the linked files above... Keep good notes, and write back with your plan as it develops. Cheers, Bob Fenner>
Re: horizontal overflows 11/24/05 Hello again. Thanks for the quick response, it was appreciated. So after some planning and designing I have came up with what looks to be a decent plan for my closed loop and horizontal overflows. I have attached a pathetic diagram of what everything will look like, but hopefully more centered. Anyways, the green circles are the current holes in the tank (this is an SeaClear acrylic 55g show tank 48x13x20 by the way). <I see> The white circles are holes to be drilled, and the square box at the top will be my horizontal overflow. Inside the overflow, I plan on having 2 1" holes drilled for bulkheads. <I'd make these larger... 1 1/2"> Will 2 holes be good enough, or should I have 3 done just in case? <Two should be fine> My plan is to use the top two green circles, which are 3/4", as returns from the sump. I have examined these bulkheads and they appear to be close to the edges of the tank, approximately 1". Will this compromise the structural integrity of the tank even though the tank is acrylic and the seams are molecularly bonded and heat polished? <Should be fine... but if it were me (and likely you as well), I would have set these in another inch or two> The next set of bulkheads will be used for my closed loop. I am planning on using the two holes in the middle (stacked vertically) as the input and the two white circles on the sides as the output. Is this a good idea, or should I switch it to the opposite? <Mmm, actually... I don't like either idea. Tell me, are you going to have valves on the closed loops intakes and discharges so you can turn this off w/o having the water go everywhere? I encourage you to consider "plugging" over these holes and re-drilling near the top... much safer...> All of these will be 3/4" bulkheads. Would it be better if I made the two white holes on the side 1" inputs, and the two in the center 3/4" outputs? Thank you so much for your help. Brian <... I'd keep reading Brian... you want the intake holes to be a bit bigger... 1" I.D. if this will accommodate your bulkheads w/o having to downsize from your pump intake volute fitting size... Bob Fenner>

Closed loop system question 11/24/05 After reading pages of your FAQ's and related posts on a closed loop system, I'm convinced! Will attempt one for my 65 gal w/25 gal fuge. I'll use a Mag 9.5, head is about 5', return pipe 1" from sump section of fuge. Question: Wouldn't a 3-sided rather than closed loop work? <As in... three discharges instead of more? Okay> More water flow, all aimed toward center of tank? <Better for this to be more complexed, multidirectional> Also,--if system is just below water level, even if jets are aimed a bit lower, wouldn't the movement of water near the bottom of a 24" deep tank be rather sluggish? <Yes... better to aim some discharges toward the bottom...> How is this negated? <Nozzles, elbows...> Could I run some PVC down lower, vertically, off the main manifold at the top? <Yes... though do bear in mind the possibility of water siphoning out... should there be a break in the lines behind/below the tank> This forum has been inspirational, to say the least. Thanks..... Barry <Thank you. Bob Fenner>

Upgrades to 240 fish only, or welcome to 2005! 11/18/05 Hello, <Hi there> I would like to begin by saying "thank you" to all the volunteers who share their time and knowledge with us. It is a tremendous service you offer, and we are all very appreciative. With that I shall launch into my situation. Thanks to Bob's excellent book (CMA), your web site, your response to my previous email a few months back, and a desire to no longer be called an "old school" marine fish keeper, <Heeee! Better than "no school!"> I have begun changing my 240 marine FO with coral skeletons, wet-dry and canister filtration to natural filtration. When I started setting up my dream aquarium 10 months ago, I decided to use a mixture of "old school" and natural methods. I believe now that this was a huge mistake, and should have chosen one method and stuck with it. I did add a refugium, but it doesn't seem to help very much with my nitrate producing wet-dry, pressure filter, and DLS material in the over-flows. <Yikes> I also added a second Euro-reef skimmer. I am still battling nitrates, phosphates, brown algae, and red slime algae. The fish, however, are all doing great, having gone from a 125 to a 240. And so I embark on a mission to modernize my tank. Here's the plan: 1) Remove all crushed coral and replaced with live sand. (Done) 2) Modify refugium to accept a micron sleeve for mechanical filtration (it is a Redmond Reef model and does not include provisions for this) then remove the DLS from the overflow feeding the refugium. <Good> 3) Remove all coral skeletons and replace with live rock (I have 200 lbs on its 3rd week of curing, plan on putting in after 4 full weeks - the water has 0 ammonia or nitrites, and the rock has only a faint odor) <Great> 4) Add approx 50 Astrea snails and 50 blue legged hermit crabs to help keep things clean (my French Angel may find the hermits a tasty treat, we shall see) (is this enough?) <As far as I'm concerned, yes> 5) Add additional lighting (I currently have 2 96 watt power compacts - I plan to double to 4 - is this necessary or advantageous?) <More of the latter, but of good application for all the organisms it will encourage that are the live rock, and their consequent part of, impact on your system, yes> 6) Remove Ocean Clear canister filter after I am certain there will be no more die-off from the live rock (this thing works great, but is a real pain to clean, so I don't do it as often as I should) <You are wise to understand yourself here> 7) Remove 50% of bio balls after 2 weeks, test water and if all goes well ... 8) Remove remaining bio balls 1-2 weeks later (is this good timing?) <Oh yes> 9) With bio balls removed, modify wet/dry to make it a sump with room for a micron sleeve mechanical filter that can be easily changed out, then remove DLS material from it's overflow <I would just use Emperor Aquatics catch bag/s here...> How does this plan sound? I have a few additional questions, if you don't mind. <Fine. Go right ahead> I currently feed the wet-dry from one overflow and the refugium from the other. Should I combine the flow from both, then separate out to each device (making it easier to balance the input flow) or is this a waste of time and pvc? <Mmm, somehow these are tied together I take it? To make sure there aren't overflow, underflow issues? If so, I would leave as is> I currently use 2 separate pumps, one in the wet-dry and one in the refugium, for water returns. in the beginning, it was difficult to adjust the flow of each so everything stayed balanced. Even now I have to make minor adjustments every now and then. <... I would plumb both these together... make them about the same height...> The real problem would come from the failure of one of the pumps. This would cause the water to fill up the device with the failed pump (though it would not overflow - I tested that). But it would cause the other pump to run dry. <Yes... not a good gamble> So if one pump fails, essentially both fail. My thought is to combine the outputs of the wet-dry and refugium and use a single larger external pump (which I already have). Thoughts? <I would definitely do this, yes> Finally, by removing the Ocean Clear canister filter, I am removing a good source of water flow. I am not a big fan of powerheads in the tank. The tank was pre-drilled with 4 holes on top. One is used for the return from the wet-dry. One is used for the return from the refugium. The other two were used for the intake and output of the Ocean Clear. I would like to create a closed loop system with the external pump that was driving the Ocean Clear, but it is a very powerful pump, and without the pressure filter aspect of the Ocean Clear, would produce too strong a current. What I would like to do is split the output into two, but then I would no longer have a hole for the input. My plan is to drill a new hole in the back of the tank (it's acrylic), just below the water level should the pump driving the wet-dry and refugium ever fail. I am comfortable drilling holes in empty tanks, but I have never drilled a tank filled with water and livestock. <Can be done... drain the water down, tape over the inside area where the hole will be... go S L O W... with the drill/bit> My plan is to do this when I am doing a water change, so the hole would be above the water line. I would drill from the back into the tank, with a friend holding a cup over the drilled area to catch most if not all of the debris. Is this a good plan or should I take everything out before drilling (which I am certain I would never do, thereby scrapping my closed loop plan)? <Can be done with some/most water in the systems> Sorry for the length of this email. And thank you in advance for any assistance you can provide. Dana McKissick <Thank you for writing so well, and sharing. Bob Fenner>

Drain Pipe Diameter 11/3/05 I just started reading your site and have learned quite a bit in a short period of time. You mentioned going to Reef Central for calculation of drain size. For 1200 GPH they recommend 1.43 inch minimum drain pipe diameter and 18 inches of linear overflow size. <I'd recommend at least two 1.5" ID diameter lines for 1200 actual gph flow> In the various responses to articles you seemed to recommend for a 120 gal tank and the above flow rate 2 overflows with 1" to 1.5" of drain diameter. I know that more is better but could I get by with a 6" x 8" center overflow box and one 1.5" drain or do I need to go to a 2" drain. <The two inch> I don't want to put more than one drain hole in the overflow because I want to use a Durso or Stockman standpipe and having 2 in one overflow makes it more difficult to debug problems w/ the standpipe. Also, both Durso and Stockman only offer the standpipe for a 1.5" bulkhead. <You can make these...> 2" may be too large for a standpipe. <... uh, no> Having one center overflow will make it easier to design and build a closed loop manifold so I don't have to go around to corner overflows. <Understood> Thanks for your time <Thank you for your participation. Bob Fenner>

Re: New System - 10/23/05 Hi Bob, <Chris> Many thanks. <Welcome> You have however prompted a couple of supplementary questions - You mention tanks re: placement & drilling of throughputs/bulkheads "they're breaking everywhere" - this concerns me!!! & I want to avoid if at all possible! The drilled holes would be behind the weir & I read your reply as me only really needing 2 drilled holes in the base of the tank - one about 50mm (2") for the 38mm (1+1/2") Durso to sump & one about 38mm (1+1/2") for the sump return pipe @ 25mm (1"). What sort of spacing & distance from the rear edge of the tank would be appropriate here? <A good two inches from top and sides... These "cube tanks" have been failing, breaking quite a bit period... undrilled... do set yours on a bit of foam to spread out small discontinuities on the surface you set yours on> <<Sorry for the confusion... I mistook your 24" cube as one of the many 24 gallon cube systems currently popular>> With a 4" deep weir would this be something like 1+1/2" (from back of tank) to 2" hole, then 1/2" to back of weir, thus equaling 4"? <Mmm, no... four inches on the front, and the side...> is this enough solid glass between the edge of the tank & the hole to avoid too much risk of a broken tank bottom? <Can't tell... have never drilled one of these... there have been a bunch sold in this past year... you might do well to query folks on the larger BB's> The holes will be drilled by the tank maker - would a double bottom complicate this? <Mmm, the drilling? No> I think I might be going to a 20 or 21" height for the tank rather than the 24" (mainly for access) - would you consider this depth preferable despite the loss of volume? <Likely only a side issue> Regarding the sump return to the main tank & reducing pipe size - Do I read you correctly to reduce the outlet 45 deg nozzles to the next size down & maybe reduce at the Tee where the sump return pipe splits into 2 lines to go around the output loop at the top of the tank (a pipe size down or more here?) <Yes... the trade off made twixt pressure and flow.> Another concern that I have is around oxygenation - with no skimmer on this system would I be likely to need to consider alternative aeration methods or would the movement in and between tank, sump & through plumbing and algae etc provide sufficient gas exchange? <I would put a skimmer on the lower refugium/sump... oxygenation not likely an issue though> Indeed I do wish I had space for a larger system! This however is a step up from my 24"x12"x12" currently, twice the size for twice the fun! When I move I'll dream again ;o) Cheers Chris <Real good. Be chatting, dreaming. Bob F>

To drill or not to drill? 9/29/05 Awesome site guys!!! Great info!!! First a horror story.... I have a 95 gallon 36x24 tank that is not drilled that has a converted 29 gallon sump. < Everyone I talk to wishes they had taken the time to have the tank pre-drilled. I'll bet that is where your story is going. > I was in the process of setting it up with a CPR 150 and the bubbles and micro bubbles where killing me from the sump back up to the tank. Last night the 29 gallon cracked and now have to start over. < Not what I was expecting to hear. > Ok time for the questions... Should I drill the tank at the top with 90 elbows straight down. < I prefer to drill the tank near the top, but not at the top. I'd recommend at least two 1.5 inch holes that are about 3 inches from the top. > Will this cut down on the bubbles and all getting rid of the CPR overflow? < Yes, but the return pump is a bigger source of bubbles, and should be the area of concern. Bubbles from the overflow can be prevented by adding baffles to the sump. > Make it quieter also... If so what size holes should I drill? < Yes quieter, and at least two 1.5 inch holes. > I am wanting to keep sps and am using a dart with 2 sea swirls. Just want to cut down on the bubbles and get the most flow for the buck. If drilling is the answer that is the way I will go if you say so. < Drilling is absolutely the way to go. I don't think anyone regrets having it done. > Thanks for all the info!!!! << Blundell >> "U" Tube overflows 9/2/05 Hey guys. I spent hours on your site last night reading the FAQs on overflows. I' ve come to the conclusion that the overflows with the U-shaped siphons are a no no. The problem is, I have a 55 gal fish and LR 'glass' tank running on a sump with an overflow box and a U-shaped siphon. Ever since I got my tank I've spent countless hours worrying that one day the overflow is going to fail. <These have their disadvantages, but are widely used without too many problems. That said, I sleep better at night knowing my tanks are drilled!> Here are my questions. Is there any way to drill holes in this tank w/o having to upset my tank environment or will I have to completely empty out the tank in order to get it drilled? <I suppose the tank could be drilled without a complete tear-down, but I would not recommend it. For a tank this small, it should be fairly easy to move all of the animals and contents to a couple of plastic bins, drill the tank and then return the animals. The whole job could be done in a couple of hours.> Can a glass tank be drilled w/o breaking the glass? Can I make this a DIY project or does it have to be done professionally? <Yes, the tank can be drilled and if you have a drill press (especially a very small portable one) it is a fairly simple DIY project. There is a small risk of breakage, but slow steady drilling pressure minimizes the risk.> Final question...do you guys have a link to a place on your site where I can get a DIY plan on drilling holes in my glass tank and attaching the overflow? <www.aquaticecosystems.com has the bits and coolant for drilling tanks as well as bulkhead fittings. They also have an outstanding technical support staff who can instruct you on the use of these items. These fittings install like a nut and bolt... no plans needed. Good luck! AdamC.> Flow with predrilled tank 8/16/05 Hey <Is for equines> ive <No such word> got a 75 gallon that is predrilled , the holes are as follows- all are already drilled to 7'8" or 15/16" , ok 3 are in the middle of the bottom glass , 2 are about 4" apart from each other about 6" below the top of the tank on one end of the tank. this tank sits in a nice stand so that the plumbing isn't seen on the one end. My question is How much flow will I get with these size of holes , I think for a 15/16" or 7/8" hole will take a 3/4" bulkhead fitting or id just buy some plumbing at home depot . I plan to use the side end holes for drainage/overflow to the 30gallon refugium/sump. The holes on the bottom will be for the return. what I really need to know is how much flow will I get out of 2 , 3/4" fittings and what size pump should I get . I can use other power heads for more circulation , the set up will be for fish with live rock, not much for any corals. ive been searching for info on a set up like this but it seems that most pre drilled tanks holes are larger than mine. I really would like to utilize the original holes so I don't risk breaking the glass while enlarging the holes to accommodate bigger fittings. any help would be much appreciated. Sean McConnell <Your grammar is atrocious... your information is archived here: http://www.wetwebmedia.com/overfloboxfaqs.htm and the linked files above... Educate yourself. Bob Fenner>

Drilling Bulkheads - 08/06/05 Dear WWM Crew, I have decided to get my 30 gallon pre-reef tank drilled and just skip messing with siphon overflows. (Thanks to reading about all the lovely problems) <<Excellent! You'll be much happier for it mate.>> But I had a few questions. <<ok>> First I gathered that tempered glass cannot be drilled but I don't know if my tank is tempered or not. It is an All-Glass 30 gallon long model (36x12x16) as far as I can gather from the previous owner it was bought new in the mid 90s. Would you think that this tanks back wall would be tempered? <<My experience with All-Glass has been that if any, only the bottom pane was/is tempered. But it's easy enough to contact the company and ask them about this one re the date of manufacture. I've drilled a few of their tanks (through the sides), both recent and unknown manufacture with no problems (if it is tempered you'll know in a hurry when it "blows out" and scares the bejesus outta ya <G>). Tanks of recent manufacture should/will be marked if tempered...but then that doesn't help you...>> If not, I am planning on having (2) 1 3/4" holes drilled to accommodate (2) 1" bulkheads. I want to have one to each side of the tank and have one drain tee off to a plenum and then connect to the other to feed the sump. I believe that they should be a minimum of 3" from the top of the tank and 3" from each side. Is this correct? <<I just did this very thing for one of my club members...when drilling bulkheads near the edge I recommend placing the outer edge of the holes equidistant from the edge at a distance equal to the diameter of the hole...e.g. - 1 3/4" hole - 1 3/4" spacing, 2 1/2" hole - 2 1/2" spacing, etc... This will let you get and still maintain strength/integrity of the pane, without guessing at it.>> I am planning on having between 600-700gph return at first but decided on the larger bulkheads in case I want/need more. Does this sound okay so far? <<Problems here I think. Be cautious of the flow calculators...better to talk to folks/query as you've done here. The reality is a 1" bulkhead will perform safer, quieter, and with less aggravation/constant fiddling of the plumbing if you only try to push about 300-350 gph per bulkhead. So...your already maxed out in my opinion. You'll need to go to a larger bulkhead if you want to turn more water.>> The tank is for 2 True Percula clowns, Euphyllia glabrescens, Plerogyra sp., Lobophyllia sp., and maybe a Fungia repanda. <<Ahh...so nice to see you're not going for the usual "reef garden" mix of organisms; you'll be all the more successful for it>> Is the flow above reasonable for these species? <<Yes...be sure to diffuse/spread throughout the tank via multiple outlets.>> If you have any other thoughts or suggestions please do not hesitate to tell me. <<Already have <G> >> I would rather know now if this setup would work than after I set it up. :) Best regards, Andrew <<And to you in kind, EricR>>

Re: Drilling Bulkheads - 08/06/05 Dear Eric, <<Andrew>> Thanks a lot for your advice, I'll heed it as WWM usually saves me from my own worst ideas. But I had a few thoughts to run by you. <<Alrighty>> If I switched out the 1" bulkheads for some 1.5" bulkheads would this fix my problem of over pumping? Or, could I make one of the bulkheads a 2" and leave the other as a 1" (the one that tees off to the plenum) and instead of connecting them just run both lines to the sump? <<A pair of 1 1/2" bulkheads should be fine. The 1" bulkheads would work, you would just need to size/regulate your return pump (maybe plumb in a gate-valve on the return side) appropriately. Please have a look through our plumbing FAQs for more on this: http://www.wetwebmedia.com/plumbingmarart.htm>> Also, I'm not drilling the tank myself but from what you said it is possible to do it yourself? <<Yes, with the right tools/application.>> Or would you have a glass company do it? I have never done it before so I don't know if I want to chance it. <<First time for everything <G>. But if you're truly uncomfortable/not handy, it might be best to fine/pay someone else to do it for you.>> I think that's everything. Thanks again, Andrew <<Most welcome, EricR>>

Bulkheads And Flow - 08/07/05 Dear Eric, I promise this is the last time I'll bother you. <<Hello again Andrew...no bother...really...I'm happy to try to assist.>> But I was thinking about it and thought that (2) 1.5" bulkheads would/could give me around 1000gph. (Please correct me if I'm wrong) <<If you're talking about both draining to the sump, then yes, is quite plausible. Though I must say, that is an awful lot of water to process through a sump on such a small tank (30g)...the slightest restriction is going to put water on the floor in a hurry. Not to mention the NOISE it is going to make. I would recommend using one bulkhead to drain to the sump in conjunction with a smaller pump (say a MAG 5), and use the other bulkhead to feed a closed-loop with another MAG 5 or even a MAG 7.>> I was planning on running a Mag Drive MD9.5. I calculated that this would give me about 800gph at 4.5' head. Is that to much to run through a sump? <<Ah, should read ahead <G>...>> I wasn't planning on having a large sump, maybe 10-20 gallons and a separate 10 gallon Plenum. I was planning on running the return into a manifold and was wondering if I should stick with the 1" bulkheads and run a smaller pump and drill a third 1" bulkhead to run closed loop. I would only do this if I had no other choice about the sump. <<Now you're talkin'... Here's my recommendation for the simplest, most manageable configuration in my opinion. Have three holes drilled for 1" bulkheads...Use two bulkheads to drain to the sump with a MAG 7 return pump. Use the third bulkhead to feed a closed loop with another MAG 7 pump. With head loss due to height/plumbing, you'll have a total flow rate of around 600-700 gph I'm guessing. By using "two" 1" overflows you will be able to increase the pump size a bit (MAG 9.5) if you determine you need/want the extra flow. Also...if given the choice...go with the 20 gallon tank for your sump...you need to ensure you will have enough "empty space" to handle the drain-down from the display tank in the advent of a power outage.>> It will only contain a skimmer, a little mechanical filtration, and a little chemical. <<and your pumps>> Will this be overloaded? <<Assuming you go with the larger of the two sump choices (20g), should be fine.>> Thanks Again (and again and again...) Andrew
<<My pleasure my friend, EricR>>

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