Drilling Acrylic Can anyone offer some experience/advice for the placement of holes in acrylic tanks in relation to the seams? I'm setting up a large reef system and I'm plumbing 1 inch bulkhead returns (two per end) in the ends of the 3/4 inch acrylic tank. I want to place the bulkheads as high as I can and was wondering if I can drill the holes right next to the top seam? My understanding is once acrylic is solvent glued it's essentially all one piece, yes? Thanks! Eric <My general "rule of thumb" is to leave gaps at least as wide as the cut out diameter from seams. You can adjust the water height in the system with plumbing distal to the tank if this is a/the concern... either ell's, tee's or valves. Bob Fenner>

- Drilling Advice - Hi crew members I am going to buy a 20 gallon long tank and have it drilled. <Hmm... this is not an ideal tank for drilling. The glass used in smaller tanks is rather thin, and even 'cheap' [float glass rather than rolled or tempered] which tends to make the panels brittle. Your best bet for getting the holes cut is to disassemble the tank, then re-silicone it together once the holes are cut.> I would like one hole for an overflow down to my sump. Then have another hole drilled for a closed loop. I do not want powerheads in my tank as you can see. <It wasn't obvious until you mentioned it ;-) > The sump will be 10 gallons. Would the hole for the overflow to the sump be ok at 1". <I think so.> And when you drill for a 1" bulkhead what size should the hole be? <1.5"> Is the same size hole for the closed loop ok? <Sure, but you could size it down to 3/4"> Or would bigger be better. <Larger would likely give you trouble - weaken the panel.> I want 15-20 times turnover. So I was going to get a mag 4 to use as the closed loop pump. Is that too much or too little? <It's going to be quite a bit - you may be challenged to keep the water in the tank rather than have it slosh over the sides. The fluid dynamics of such a small box are going to be a challenge. Any chance I can convince you to try all this with a larger tank? Your overall plan is good, but I'd really like to see you attempt this with something larger.> The tank is going to have zoanthids mostly. No fish. Also would it be ok to drill the overflow in the side pane of the glass just about 1/2" below the top of the glass? <Sure.> The hole for the closed loop can go anywhere right? <For safety's sake, I'd put that just below the water line. If you put the bulkhead in the bottom of the tank and something in your plumbing fails, you will be quite sad.> Thanks, Karl <Cheers, J -- >

- Drilling Advice, Follow-up - Hello JasonC <Hi.> Thank you for the fast reply. <My pleasure.> My hotmail account is not working good and I was afraid you guys didn't get my last email. I know the 20 gallon tank is not a great size to work with. It is all I have the room for and am allowed in my rental. <Fair enough.> It is an acrylic tank so drilling should be better right? <Oh sure, much better.> And if I went for a 3/4 hole for the closed loop and used a Mag 3 (350gph) would that be better or more safe so that water does no splash around. <I would plumb it in externally at first so you can experiment before you commit to drilling the hole. The Mag 4 isn't really a beefy pump and if I recall the outlet is 3/4" so you're not really going to be holding it back much.> Thank you again Karl <Cheers, J -- >

Finding Aquarium hardware/gadgets Dear Sir or Madam: I am looking for a clamp or bracket that will secure a drain hose to my refugium sump.  The bracket must fit over the top of the glass tank and must have a ring or clamp that I can use to secure a 1" or 1-1/4" drain hose.  In most refugiums, this function is performed by a bulkhead that is secured by a horizontal plastic or glass cover over the tank.  Such a horizontal cover is impractical for most do-it-yourself downstream refugiums and I am looking for a simpler solution.  If you know where I can obtain such a bracket or clamp, I would appreciate it. Thanks very much. Regards, Paul. < For any kind of bracket or gadget I always check out aquatic eco systems @ aquaticeco.com. This is a great site for DIY aquarists. Get their catalog.-Chuck> Glass hole driller in San Diego Hello, Can anyone on your crew recommend someone in San Diego that can drill a couple holes in the back of my glass aquarium for a closed loop circulation system. It's non tempered. Thanks. Peter <Well, we actually live in SD and I still don't know... but do know how I would proceed. Check the "Yellow Pages" or their equivalent under "glass" and call the suppliers... IF the tank is not built yet.... do consider having it constructed by Lee Mar... they do a great job... and are reasonable for what you get. A bunch of retailers can help you here... but I'm most familiar with Ron Elander, Octopus' Garden... Oh, do go by and check out his new re-location. It's fabulous. Bob Fenner> Drilling a tank I have a 2 month old Reef Ready Oceanic 58 gal tank with a 1" bulkhead in the bottom.  The tank is currently set up with sand, live rock, fish, etc.  I would like to re-drill the tank for a 1.5" bulkhead to accommodate a larger pump (MagDrive 1800).  My question is, can I drill the tank if I drain only the overflow box or does the whole tank need to be drained? Thanks, Randy <The whole tank... needs to be taken down, drilled while empty. Bob Fenner>

Acrylic Real quick. With acrylic to glass contact, the 100% silicone I have read about in the F&Q's will work right? <I wouldn't trust it for aquaria... but for little troughs/trays/filters...maybe> And definitely for acrylic to acrylic.  <do use proper acrylic glue for this> About cutting acrylic for bulkhead fittings. I have hole cutters for doors and such. this will work fine, <yes if sharp> and put the silicone on either side of the bulkhead and let stand 24 hrs.  <OK... but neoprene gaskets that come with many bulkheads compress nicely and are more reliable> Great job guys, Bryan. <thank you kindly, Anthony>

DIY Overflow Hi, <<Hello,>> I've been reading your FAQs since I started my first marine aquarium this year. It's just a 29 gallon tank with a couple fish, some crabs, and just recently 2 anemones. I figure that this is my learning tank before moving on to something larger. I have a Prizm skimmer, Penguin Bio Wheel power filter with a Fluval surface skimmer attached, and a Zoo Med powerhead behind the rocks for extra circulation. Anyway... I just added a new 200 watt Ebo Jager heater (also behind the rocks), and a CustomSealife SmartLite to the mix, and I realized that space is getting tight... Because of the light I can't reach the skimmer to adjust the flow without removing the light, and I don't like the heater laying across the bottom of the tank. I realized that I have several 10 gallon tanks collecting dust in the garage, so my natural thought was that it's time to add a sump to my learning experience. That would allow me to move all the mechanical devices below the tank except for the power head (which is the only piece I've really been able to conceal well anyway). I've been looking at overflow boxes, and the ones that are available are way too big for this little tank, and too expensive to boot, since when I do get a larger tank it will be drilled for a sump anyway, so why blow $70 on something that I won't be able to use on a new tank down the road. After looking through the DIY plans online I just had an interesting idea about making an overflow box, and am seeking an opinion as to whether it would be a good idea. I read one of the plans where a person used an old power filter as the outside box. all the parts were gutted, and the hole where the pump goes was used to place the bulkhead for the plumbing. My thought was... Why gut the filter??? Add the overflow box onto the front leaving the filter tube in place so that it's inside the box (cut down if too long), and why remove a perfectly good pump??? Just add a piece of acrylic to divide the media chamber drilling the opposite side from the intake for the bulkhead. Now you have an overflow with a priming pump built in... Just plug it in until the siphon starts, and then unplug... If the siphon breaks you can just plug it in to re-prime it. Any problem with this that I'm missing? <<Only if you forget to unplug the pump... the pump mechanics would also reduce flow when the pump is shut off. Although this is a neat idea, it's probably not optimal.>> Aside from the fact that it would be limited by the diameter of the intake tube, but for a small tank it could be just the thing, and who doesn't have an old power filter or two laying around wasting space?  <<True.>> Thanks, Jeff Cowles
<<Cheers, J -- >>