Phosphates and Carbon

You now may have a full blown mystery although most likely the phosphates are coming from food. Looking at your sig line you have an overstocked tank and the food is definitely the most likely culprit. You should go to 15% ot 20% weekly water changes to help keep the PO4 steady. I would definitely look into macro algae refugium. A HOB type will work. This will help you export more PO4. A reactor or canister filter with GFO will be a good idea also.

 

Yea I need to update my line. I haven't feed the tank in 24 hrs. I do add small amounts of phyotofest. Never used tap water to set up tank. Tank has been running six months. I also feed with tank water in a shot glass with frozen mysis then I drain off the water in the sink and add just the meat. I'm doing all I can. The carbon is the only thing I can think of. My heat went out recently and I lost most of my fish! Part of the reason for the large water change. I have been doing previously 20% bi weekly.

 

If your PO4 levels were that high for a period of time, your rock and sand absorbed PO4 as well. Therefore, the rock/sand will continue to leach out phosphates until they have come back into equilibrium with the water column.

You'll be doing a lot of water changes for a long time to rid yourself of this problem, unless you start running a PO4 absorbing media (ie - GFO).

 

I would have to agree with Evolved, this is going to be a process; not an over night fix. You will be able to correct the problem with the techniques you are using and with the advise given by your fellow reefers. Keep up the work it will straighten out for you.