After 2 weeks of dosing PO4
5.5 footer PO4 now is 98 ppb or or 0.3 ppm. (Dosing Iron supplement to control PO4)
Can either increase iron dosing or reduce PO4 dosing to drop PO4 level to 0.1
2.5 footer PO4 is 200 ppb or 0.6 ppm. (This tank has no skimmer and PO4 is control by PO4 minus in bag
Need to increase phos minus change frequency from 14 days to 7 days and monitor till PO4 level drop to 0.1 ppm