High nitrates and refugium light cycle

sprouseod · Jul 4, 2018

I can't seem to get my nitrates below 50. I have a fairly light bioload with just 6 fish and a 100 gallon total tank volume (RSR350 with Crystal Reef Triton sump and Kessil H380 light). The tank has been up and running for about 10 months but I just installed the new sump about a month ago. The refugium is about 3/4 full of chaeto. I have the H380 set on a 12hr cycle at night. My question is should I run the light full time? Will that lower the nitrates any fast?

Thanks
Richard

Potatohead · Jul 4, 2018

How much do you feed? Have you verified your nitrate is actually that high with a second test kit?

sprouseod · Jul 4, 2018

I feed just once a day, usually fine pellets. Just enough to keep the fish busy for a few minutes. I don't have a second kit but I am going to mix up some fresh saltwater and test that as a control. I've only used RODI water from the beginning. I started dosing 10ml/day of nopox a week ago and I do see the skimmer kicking in more. I've had problems with nitrates from the beginning. Never seems to come down much even after some large water changes

Potatohead · Jul 4, 2018

Seems weird to have a low bioload and not much feeding and have them so high, so I would double check. Testing the newly mixed is a good idea.

sprouseod · Jul 4, 2018

So I tested with RODI water mixed with Red Sea Pro salt and the nitrates are zero.

Potatohead · Jul 4, 2018

To answer the original question, running the light longer will help assuming the macroalgae is actually growing well. Continuing the carbon dosing will help a lot more.

lion king · Jul 4, 2018

What;s the flow going through your refugium. I never had great results when my refugium was in a flow though design sump getting high flow. The algae actually needs time to uptake, flow trough my macros are now less than 300gph. Lengthening the light cycle is an option to try. Dialing in the nopox takes a little time and that will get you there as well.