Temperate Marine Filtration Without Live Rock? 6/2/09
I love your site - thanks for all the great advise!
<We are happy it is of such good use!>
I have a temperate (cold water - 60 degrees F) tank that's been running for a year.
<I have been contemplating such a tank.>
I keep southern California animals (Bimac octopus, strawberry anemone, gorgonians). The octopus is a messy eater, and eats a lot; and the other creatures need to eat a lot too, so I went with a wet/dry filter to be able to handle the large dumps of waste. I don't use live rock because I don't want to introduce anything living thing that is not local, and I find that to keep the nitrates between 10 and 20 I need to do at least two 20% water changes per week. I'm going to upgrade to a 90 gallon tank, and I want to design a filtration system without live rock that can handle the load, and reduce nitrates better than my current system.
<Have you considered acquiring "local" LR?>
Specs on my current filtration system:
50 gallon water volume
Wet/Dry with 5 gallons of bio balls and a prefilter (replaced every 2 or 3 days)
Aqua-C Remora skimmer
5 inch deep sand bed in tank, with Tunze 6045 for flow (Rated at 1189 gph) and about 60% of tank floor covered with non porous rock
Ammonia and Nitrite are always zero, but Nitrates have always accumulated steadily, requiring the 40% per week water changes.
<Wow!>
I'd like your suggestions for an improved filtration system that can handle the special needs of my cold water tank. My current system works, but the frequent water changes and frequent replacement of the prefilter floss on the wet/dry are a pain. My special needs are:
1) No live rock allowed (but "dead" porous rock (limestone?) would be OK)
2) Heavy feeding compared to a tropical reef: 3 times per day for gorgonians and anemone, plus heavy intermittent feeding (every 2 or 3days) of octopus.
3) Cold water slows down biological processes (my tank took 5 months to cycle)
For the upcoming 92 gallon corner tank I'm planning to use a wet/dry with 12 gallons of bio balls to handle the heavy bio-load. To reduce nitrates I was thinking of adding a remote deep sand bed (5 gallon bucket 3/4 full of fine sand) and 3 liters of ceramic noodles in the sump. I'm also going to upgrade to a big skimmer (ASM G-4 clone). What do you think? What would be better?
<What you list above will work.>
Could I remove the wet/dry and use dead porous rock (lime stone) instead of live rock and get the same filtration benefits as LR?
<Eventually, after quite a bit of time.>
How much rock would I need to handle my increased bio load?
<A few dozen pounds.>
Given that it took 5 months for my bio balls to cycle in my cold tank, how long might it take the dead porous rock to come up to speed?
<Likely the same.>
Can I use inland, quarried, limestone instead of buying expensive liverock and killing it?
<Compared to tropical LR you are probably better off with the dry rock. Do look into getting local, CA, LR.>
For denitrification purposes, how should I deploy ceramic noodles in my sump? Tightly?, loosely? I've read that they need low flow to go anaerobic.
<Noodles will provide no denitrification, this will come from your DSB.>
Thanks for your help!
<Welcome, Scott V.>

Coldwater Reef Systems Thanks for the quick reply Bob, The system I have in mind will have a plenum bed filter in the display tank. The sump will have approximately 15 water changes per hour flowing through it.(15 changes of display tank water) Connected to the sump will be a permanently lighted refugium with very low flow, 20 GPH or so. <Sounds good thus far. Stocking plan? Bob Fenner>

Cold marine open system Hi oh knowledgeable ones, <Don't ask me how to work on cars, about sports... most anything for that matter> I was wondering about water cycling rates provided you had an open system.  I have been doing a lot of contemplating and the most cost effective and probably healthy system I can think of is to have ocean water pumped directly from the bay through some sort of filtering system, mostly to keep out other animals, and then have the run off head right back out to the bay. <Have been part of designing, constructing and mainly trying to fix such systems.>   I figure with a setup like this, the filtering would be less than a closed system and a chiller would be unnecessary or small. <Yes to the latter, no to the former... many problems with new water... need for BIG pumps, filters... best to consider timers, switches for recirculating except during incoming tides for instance> Am I wrong in this thinking?  Anyway what sort of GPH flow rate would you deem adequate in say a 2000 gallon tank? <Mmm, depends on sorts of systems, stocking densities... but one to a few volumes per hour likely... As stated, do consider a secondary recirculating system for the eventuality that you'll have to do so. Bob Fenner> Thanks, Brian Hoyt Chiller Fittings/Locating PVC Components - 12/20/06 I have purchased an Eco Plus 1/4 hp chiller for my 100 gallon reef tank. <<Ok>> I would like to run it in series, in my return. <<As in "in-line" after the return pump?  Doable...and is how my chiller is plumbed>> However, the fittings on top appear to be 1" hose thread. <<Not "hose thread" likely but rather is "pipe thread"...there is a difference>> I need to run 1" PVC. <<Agreed>> The chiller comes with some cheesy little fittings for vinyl hose.  I cannot find anyone that carries a 1" hose thread PVC fitting of any kind. <<...?!>> Do you know of anyone? <<Any home center (Lowe's, Home Depot, Menards) or a well stocked hardware store should have these.  If you don't have anything like this nearby, you can order on line from U.S. Plastics (http://www.usplastic.com/catalog/variant.asp?catalog%5Fname=USPlastic&category%5Fname=13670&product%5Fid=18098&variant%5Fid=28463) Thanks for all of your help over the years.  You guys <<and gals>> are a great resource! Mike <<Happy to be of assistance Mike.  Eric Russell>> Moving sump to basement, Increasing Bulkhead Size/Plumbing a Skimmer and Chiller - 04/15/07 Hello Crew, <<Hi Jerry>> Thanks for your help in the past on lighting, now I could use your help on planning plumbing. <<Let's see what we can do>> I want to move my sump, skimmer and pump (and new chiller) in the basement. <<Ok>> It would run through wall with 2x4 studs and 2x4 plates which limits pipes to 1.5 or less.  My current 110 acrylic reef tank has overflow 1" and 3/4 return with Little Giant 4 pump.  Can the 1" be enlarged with Roto-Zip or Dremel tool or a file to accommodate a 2" bulkhead? <<It can (using the Roto/Dremel tool), or even with an appropriately sized hole saw like those meant for cutting holes in wood (the "bi-metal" blades work the best IMO)>> Will the 3/4 return be enough for GenX Mak 4 (1200gph) after 12' lift and split for chiller and skimmer? <<It will, though I would increase this to 1", since you're recutting new holes anyway.  Also, I don't recommend "splitting" the pump to feed the skimmer and chiller.  This sort of "balancing act" just doesn't work.  It's not so much an issue with the chiller, but you will find yourself having to constantly fiddle with the skimmer to keep it "tuned" due to the almost constant variations in flow because of fluctuating fluid dynamics'¦best to use a dedicated pump for the skimmer in my opinion>> Would you recommend turning both bulkheads into overflow to sump and return over the tank? <<Since the sump will be located remote from the display/out of the living area and if your intent is to maximize flow through the sump to reduce the need for ancillary water flow devices...absolutely>> Thanks so much, Jerry <<Happy to assist.  EricR>>