I'm preparing to set up another coldwater aquarium and I am considering using live rock as the main filtration. I'm concerned that live rock may not be able to handle the bio-load in a heavily stocked and heavily fed cold water tank, so I'm looking for feedback from someone who has used live rock in such a tank. If you have a cold water tank with a heavy bio-load (animals, feeding):
1) How is your water quality?
2) How much live rock (lbs per gallon) do you have, and what type of live rock?
3) What temp do you keep your tank?
4) What other filtration do you have (skimmer, sock, refugium, DSB etc)?

Thanks for any feedback you can give me.

I am using 3.5 lbs of what looks to be Fiji live rock in combination with locally collected rock. I also have
pieces of LR rubble inside my AQ 30. For skimming I run a Taam Nano Skimmer which is perfect for the
size of my tank. (5.5) Auxilary filtration is accomplished by a Zoo Med mini canister with sponge, carbon
and ceramic bio media. Water quality is great for the most part. I did have the occasional ammonia spikes due to over feeding with meatier foods such as chopped up table shrimp. I have since excluded that from
the menu and use much smaller mysis shrimp instead. I do once a month water changes and topoffs when
needed. Tank temp currently is 52 degrees. The live rock seems to have worked well for me
but at a much slower rate. With that in mind I make sure to balance out the feeding as to not over
burden the biological.

H

Thanks for the reply.
Do you have a reading on your nitrates? I wonder if the ceramic in your canister filter houses anareobic bacteria, or just aerobic, do you know?

I just did my regular battery of tests. My nitrates tested at 0 along with ammonia and nitrite levels.
If I were to guess what type of bacteria are in the ceramic media I would think it would be anareobic.
How can you tell if it were aerobic or aerobic bacteria. What should I look for for either?

H

Anaerobic bacteria only live where there is no dissolved oxygen in the water, i.e. where aerobic bacteria, closer to the outside of the rock, have already used up all the available dissolved oxygen. I don't know how far below the surface of live rock, or ceramic tubes, that starts to be the case. Ceramic tubes are designed like macaroni, so that there are no places that are deeper than 1/2 the thickness of the tube wall. My guess is that ceramic tubes provide no anaerobic bacteria, but that your live rock does, and that your amazingly low nitrates are a result of your live rock alone.

You have about 0.63 pounds of live rock per gallon in a heavily stocked, and presumably heavily fed tank, and your nitrates are super low, so that seems to prove the ability of liverock to get the job done, even in a cold tank. Thanks for the feedback.

Anybody else have experience that confirms or refutes this?

www.temperatereef.com Ask pufferfreak he can probably help you out.