can't reduce phosphates


New member
I've been dealing with high phosphates for at least 6 months now. Here is what I've done:
1.10-20 gallon weekly water (ro/di) changes for a several months.
2.Switched to feeding frozen foods (prime reef & formula 1) only once a day or every other day.
3. Got a phosban reactor running rowaphos
4. Got a CPR HOB refugium full of chaeto, removing it every 2 weeks.
5. Put a second seaclone skimmer on the tank (had from another tank)

Yet my phosphates still measure off the scale on the seachem test. I've tested the test kit with a supplied reference sample and test my nsw which both are zero. I've pretty much given up at this point. I can't keep LPS corals and coralline algae will not grow since the phosphates are so high. Any thoughts????:confused:


New member
If your phosphates are really high... I would recommend changing out the rowaphos once every couple of weeks and reduce feeding to every other day at the very least until you see them start to come down.... Once you see it coming down test nearly everyday... Once it stops coming down or goes up it is time to change the rowaphos right away :)

Randy Holmes-Farley

Reef Chemist
Premium Member
At least 3 ppm. I've already used 500 ml of rowaphos in the reactor.

Large water changes and more use of phosphate binders are about the only way to deal with a value that high. The phosphate binder is depleted very fast with phosphate that high. Maybe 1 day or less, assuming you have good flow through the reactor.