If you can get your test kit readings to zero for both nitrate and phosphate with the cheaper test kits, I find this is really all you need. This will help IME when dealing with algae type problems along with fish.....etc, that will eat it.
If your phosphate level is as high as 2.5, then you may need to replace your GFO fairly often (maybe every three to four days) until the levels reach zero. At that point you can increase the time period before you change the GFO.
To reduce both your nitrate and phosphate levels, dosing a carbon source is effective IME. This will take time to see results.
I am particularly interested in the affects of AlgaeFix Marine on Bryopsis. Keep us posted.
