Zoas browning out


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Oct 11, 2018
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Monterey, California
Hello all. I have numerous zoa colonies on a zoa garden that are under about 200 PAR under 24" T5 ATI actinic, 24" T5 ATI blue plus, and some of a Kessil A360x running at 100% intensity, 20% color (boosted UV, and a bit of red). They seem to be browned out on the polyps getting high light and keeping their colors on polyps just next to these if they're turned away from the direct upwards light. It could be that they are instead turned towards the glass and receiving high reflected light.

I'm looking for an answer on are the getting too much light or not enough light?

They do seem to have an incessant bacterial infection as well. My larger palys are not nearly as big as they should be and I've never been able to solve the issue, though treating prophylactically with chemi-clean seems to help them out for a few weeks. Starting to do that monthly to try and defeat whatever bacteria I have in the system. I do plan to dip the whole darn rock in H2O2 at some point to try and resolve that, but it seems that light is more of the culprit for my zoas (as opposed to larger paly-like polyps).

Sticker shock

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Oct 5, 2019
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North Shore, Massachusetts
In my experience, zoas and plays that are not getting enough light will stretch towards the light. Those that get enough are typically pretty flat against their rock. I don’t think I’ve ever been in the situation where there was too much light, so anything on that would be more of a guess.

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