My outbreak of alage over the last several months led me to borrow James' phosphate test kit last week and had pretty high levels at around 1ppm w/ his Salifert test kit, probably attributed to the way that I broadcast feed ever day. I have done several things to correct the high levels. I traded my hugh wrasse to Norman so I will not have hugh chunks of food that are uneaten that need to break down. Now that the wrasse is gone I can actually have a clean up crew of snails and crabs. The wrasse always made quick work of anything of that nature that I would add. I started running Rowa Phos through my fluval at a very slow rate and my levels are down to .1 ppm after a day. I will continue to use it and encorperate it into my system for long term use. It is nice to use a product that actually does what it claims to for a change.
GFO (granulated ferric oxide) is great. I think the trade off of not being able to rejuvenate it is ok since it works so well and doesn't freak out Toadstool/Devil's Hand corals like the ceramic (aluminum based) ones do.
In the both threads high alk was also an issue and a suspect. IMO a GFO should be the next thing you should add to your reef right after water. If you have fish you have Po4. This would make sure that your Po4 levels stay low and to try to remove it before it precipitates in to CaPo4. If you use it regularly it shouldn’t cause harm to sps.
