pocillopora turning white

[Snookster]

I have a purple pocillopora that's been turning white on me and I'm looking for causes.

The only change I've made in the last few weeks, is that I changed out my GFO.

Will removing PO4 too fast or driving it too low be a cause?

I've gone from well over 0.03 down to barely perceptible on the saifert test kit in about 3 months. All other params are good. Other SPS colors are good, although poylp extension isn't great. My duncan is a little short polyp'd as well. Zoas seem to have mixed opinions (but they always do).

If so, what's the safest/best way to bring it back up without getting an algae pasture growing (i.e., lots of food)? I turned the reactor feed down to a tiny stream barely above a drip and cut the vodka dosing down to 2 ml nightly.

If not PO4, any other thoughts?

Thanks

 

[sabo]

I've got a green pocci that just doesn't like my tank. Same bleaching, whereas as all other SPS is fine. Funnily I have a purple pocci that's doing fine. Quite amusing that the one coral some people call a pest doesn't grow well in my tank.

 

[rogergolf66]

Po4 stripped to low from the tank can be a cause. I have had it happen to me before. My filtration does such a good job I have actually purchased dry phosphate and dry nitrate. I have never used it but I have really considered using it at times. I liked your reading of .03 i personally c my tank doing its best when I can find a couple small patches of algae in my tanks. I Just keep them in check with a tooth brush when needed. I really don't test for nitrate or po4 anymore I watch the glass on my tanks and I watch for algea growth throughout the tank. But that's only if u have been running your tank for a long time u just learn your own tank. Hope I answered ur question.

That all being said it could be many other things too but when u say the other don't have good polyp existent ion that's what I would lean toward.