So little background on what is going on. I have a tank that is up and running for 3 months. I cycled the tank empty for a month and now have had fish in the tank now for 2 months. It is a 40 gallon C-Vue tank. In it is a Midas Blenny two clown and a fire fish and some snails. I used the API test kit the other day and it showed my nitrate were high. I am talking RED over 80ppm I change out about 5 gallons of water every week in my tank. Once I saw the test I did another 5 gallon water change and used the test kit again and it is showing red again in the 80ppm marker. As far as feeding habitats I feed a pinch of flake food in morning and a Mysis Shrimp cube at night. I have since ordered a Hannah Nitrate checker that comes tomorrow. Now say when I get the Hannah Nitrate checker and I test the water and it is still high. How much water should I be changing out on my weekly cleaning of tank to affectively get it down to the desired number.
High Nitrate False test or real thing?
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Jay Hemdal
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Two tricks: mix up some new seawater and test that, should read zero. Then, dilute your tank water 1:1 with RODI and test that, just to ensure you aren’t off the testing scale.
Jay
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redfishbluefish
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Like Jay's suggestion. Start there. And could it be real.... First off, I'm not crazy about API test kits. Second, a little history about your rock. If it was dried, preused rock that was not cured, nitrates that high are possible.
Assuming testing checks out, water changes are the way to go. I'd suggest going larger, not not more than 50% at any one time, until nitrates start coming down.
Assuming testing checks out, water changes are the way to go. I'd suggest going larger, not not more than 50% at any one time, until nitrates start coming down.
Mooneyhan22
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I have been dealing with higher nitrates on a Biocube for the last year. I started with all dry rock and several bacteria additives. Even with minimal feeding my nitrates would get up in the 70-80 range even with cheato growing in a refugium. I read many threads on this forum and most suggested daily water changes until you get them down. You can use a calculator to see how many water changes you need. Nitrates minus (Nitrates divided by tank volume times water change volume). I have since added a media reactor with sea hem denitrate to help bring them down. What I gathered is that the dry rock just takes a long time to mature to really be an active part of your filtration.
redfishbluefish
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Without curing the rock, there is your source of high nitrates. Again, water changes are the way to go. And I'd do 50% changes until the numbers come down.
Randy Holmes-Farley
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My Tank Thread
FWIW, nitrite leading to a false high nitrate is common with nitrate test kits due to the chemistry involved, but seems fairly low in the Hanna kit:
www.reef2reef.com
Hanna low range nitrate accuracy, nitrite interference
Anyone have any feedback or knowledge on how the new Hanna HI781 nitrate checker might be effected by nitrite (NO2), or it’s accuracy at the very low range? @Lasse started a thread over in the Hanna instruments forum about it. I thought I might bring the topic over here to get some more input...
www.reef2reef.com
Azedenkae
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Check nitrites. If you have nitrites, it could interfere with the API nitrates test and register a false high reading.
Also, a 5 gallon water change won't really make a dent with 80ppm nitrates. With your 5 gallon water changes, if the reading is 80ppm, you'd only decrease it by 10ppm. If it is higher than 80ppm, yeah even after a 5 gallon water change I would not be surprised that it still reads higher than 80ppm.
