Nitrates soooo high! Can’t get them down. Help

[J. H.]

Nitrates come from protein. Fish that size (in order to grow) are typically being fed around 4% of their net body weight measured on net dry weight basis on a daily basis (on average.) Feeding has to be at least 2- 2.5% merely to maintain their current size, so if they're growing, 4% is likely as low as it is. (Sub adults need a basic daily amount to grow properly, and although you might be feeding them even higher amounts, it's difficult to have healthy, attractive fish by feeding them less.)

You also might be feeding a higher or lower rates of protein or the fish might be slightly larger or smaller. The direction of the analysis isn't materially different. Molecular protein includes ammonia and ammonia becomes nitrates.

The fish stock in your tank works out to around 2.25 lbs. Feeding 2.25 lbs of fish 50% protein food at that rate works out to 19 ppm of nitrates per day.

19 x 7 = 133 nitrates per week. Doing 50% WC each week will lead to a static rate of 130-250 ppm.

If each of your fish grows by 1 inch and feeding is kept at 4% of net weight, the nitrates will jump from 19 to 30 per day. I'd say you should be doing 50% daily changes and are heading quickly towards 75-90%. Yes. Overcrowded for that rate of feeding and water changes. As they all are still growing, the numbers will increase geometrically.

Can you post all the math? I can't seem to follow you here.

 

[jaws7777]

Dr strangelove is spot on. No amount of filter cleaning is going to resolve this issue. Tank is overstocked and most of the fish still have allot of growing to do so it will only get worse.

Rehome some fish starting with the aro. 125 is way too small for it

 

[JohnnyTBags]

Rehoused my Aro yesterday on Christmas. Lucky my cousin has a pond.

I jump started my 90g I had in garage. Hopefully ill able to peel out a few more to go in there. Once that happens, I’ll see what I have left, do the math, and re house as necessary. Thank you all for your help.