weirdly high nitrate and phosphate in only one tank
Question for the experts: I've got three tanks (4 gallon, 9 gallon, 54 gallon) that I fertilize with the same stock fertilizer solutions and do water changes with using the same remineralized water.
In the 4 gallon tank, my nitrates and phosphate (~40 ppm, 5 ppm) are much higher than the other two tanks (~5-10 ppm, 0.5 ppm). Not sure what could be going on, this discrepancy only popped up a couple of weeks ago, until then parameter values were much closer to the other two tanks.
Any ideas what may be driving this discrepancy? Thanks!
There was only one catch and that was Catch-22.