I find what your doing fascinating. I also have added siporax about two months ago and my nitrates dropped from between 5-10 ppm (salifert tests) to just this week to .75- 1 ppm (Red Sea pro test). My phosphates have only come down with GFO though.
So is your thinking that as the nitrates drop so will the phosphates. I just haven't seen that take place.
I understand when carbon dosing, the increased bacterial population is consuming both nitrates and phosphates something to the tune of the redfield ratio but is that different from siporax supporting denitrifying bacteria and nitrifying bacteria. Do the siporax supported bacteria also consume phosphate approximately to the redfield ratio as well or just effect nitrates primarily?
Second point, siporax in a media reactor is a great idea and should allow for low flow which apparently lets the bacteria kick into high gear, I believe due to anaerobic conditions being improved. I have heard it suggested to avoid placement of siporax in the overflow box because of the likelihood of detritus accumulating and filling all the pore spaces.
