zoas not opening like they used to, still multiplying


New member
A couple weeks ago I tried phosguard to help fight an algae outbreak in my mixed reef. after a couple days I noticed both of my zoas closed up. All other coral are doing well, so I continued phosguard use for a week before removing. Replaced with plenty of carbon to try to get any contaminants out of the water, and have done water changes.

The I have a couple polyp frag that has been pretty much back to normal, open most of the time, but the other frag/colony (15 polyps) has only had maybe half of it's polyps open or less at a time, and always seems to by the sames ones. The polyps that do open don't open as wide as they used to before phosguard. Oddly though, even though they haven't opened much in the last week, I have noticed that they are still multiplying (11 polyps to 15 in a little over a week). Didn't grow at all during phosguard use.

Is there anything I can do to get the polyps to start opening again, or is there little hope that they will go back to the way they were?



Staff member
RC Mod
CHeck your alkalinity, just in case. If it should be the iron, GFO saturates as far as absorbing phosphate at a certain point, so it may (ask a chemist) become inert in the capacity to annoy anything. I've never had a coral upset at it, but mine are lps. If the annoyance isn't alk, and you're worried about the GFO, run PolyFIlter: that will actually remove iron, as I recall---turns it blackish.


New member
phosguard is actualy aluminum based, not iron based like GFO. I've read (after I started having problems) that some people have good luck with it, and some bad. Other than my zoas, everything else was fine. So I'd beleive that some people have good luck with it. The zoas never closed up much before that was added though, so that's why I think t was the phosguard. My alk was low when I removed the phosguard, but I've since adjusted it back ti normal and has been there for a week or so. I do run lots of poly filter and carbon but hasn't fixed the problem


New member
What was the po4 reading before and after the phosgaurd. You may have dropped the phosphate very quickly. Also its only meant to be used for a few days at a time.