I recently made it my goal to figure out why the heck my phosphate level would continually rise despite my best effort to reduce it. I was running Phosguard in a media bag in my sump (yes I know a reactor would be better), skimmer, and an algae turf scrubber. My tank is a 40 breeder with a 20L sump so probably roughly 50 gallons total water volume. I feed 1 cube of frozen per day.
Out of all the methods I was using, the ATS showed the most promise as it initially lowered my phosphates. However, it eventually reached a point where it could not get the level lower than ~0.15. I was very confused at this point because between weekly water changes my phosphate would creep up to 0.25 - 0.35! That is when I stumbled upon a nitrate dosing post on R2R...
I tested my nitrate level and sure enough it was undetectable. I had known I had low nitrates based on previous testing but I thought that this was a good thing because having high nitrates is considered bad for your tank. However, my undetectable nitrates had basically become a limiting factor for organisms in the tank that take up carbon, nitrate and phosphate from the water. I went to Lowe's and bought a nitrogen source (KNO3 in Stump Remover) and mixed up a batch of it.
My first dose was 15mL which, based on the concentration I mixed up, was supposed to raise my tank's NO3 level by 1 ppm. I retested after an hour and read 0.75 ppm! I let that first dose do its thing for a day and retested after 24 hours...no detectable NO3. I then tested my phosphate level and it had been CUT IN HALF from the previous day. Nothing I have ever done has shown such immediate, significant results. To me this was verification that my undetectable NO3 had become a limiting factor for my tank.
I am going to continue to conservatively dose KNO3 until I am comfortable with my nitrate and phosphate levels. I guess one of the main concerns is that you can completely bottom out your phosphate level which results in bad things happening to your coral.
Does anyone else have experience with this? Success stories, horror stories?
Out of all the methods I was using, the ATS showed the most promise as it initially lowered my phosphates. However, it eventually reached a point where it could not get the level lower than ~0.15. I was very confused at this point because between weekly water changes my phosphate would creep up to 0.25 - 0.35! That is when I stumbled upon a nitrate dosing post on R2R...
I tested my nitrate level and sure enough it was undetectable. I had known I had low nitrates based on previous testing but I thought that this was a good thing because having high nitrates is considered bad for your tank. However, my undetectable nitrates had basically become a limiting factor for organisms in the tank that take up carbon, nitrate and phosphate from the water. I went to Lowe's and bought a nitrogen source (KNO3 in Stump Remover) and mixed up a batch of it.
My first dose was 15mL which, based on the concentration I mixed up, was supposed to raise my tank's NO3 level by 1 ppm. I retested after an hour and read 0.75 ppm! I let that first dose do its thing for a day and retested after 24 hours...no detectable NO3. I then tested my phosphate level and it had been CUT IN HALF from the previous day. Nothing I have ever done has shown such immediate, significant results. To me this was verification that my undetectable NO3 had become a limiting factor for my tank.
I am going to continue to conservatively dose KNO3 until I am comfortable with my nitrate and phosphate levels. I guess one of the main concerns is that you can completely bottom out your phosphate level which results in bad things happening to your coral.
Does anyone else have experience with this? Success stories, horror stories?