Zoanthid losing color and growing longer tentacles

[Pascalereefer]

Good afternoon! My green zoas are becoming a paler green, and developing long, thin tentacles. You can see a significant contrast between the attached photos. My tank is about 10 months old. I've got zero nitrates and phosphates. Moderate flow in the area I have this coral. I had a major GHA outbreak and had to dip the rock these guys are on in hydrogen peroxide. It took them about a week to open up again after (and GHA is gone). The other item of note is I started running my 2 AI Primes at only 50% to reduce GHA growth. Any ideas what could cause this change?

 

[Tired]

Zero nitrates and phosphates will starve your corals, particularly zero phosphate. Crank those up to a minimum of 0.03ppm phosphate and 5ppm nitrate, preferably by dosing to get it up quick, and stop doing water changes unless there's a need to replace minerals or lower nutrients.

You may have an initial surge of hair algae from the increased nutrients, but if you keep up with manual removal of long tufts and a proper CUC, that should fade out and be replaced by beneficial algae. Lack of nutrients prevents beneficial algae from growing, which lengthens your ugly stage.

 

[MikeCRK]

This^^

I had similar on one zoa, pumped PO4 a bit and problem solved few days later.

 

[Pascalereefer]

Thanks for both posts! I think I'll try removing the gfo and see if my phosphates come up a bit!

 

[Spare time]

Thanks for both posts! I think I'll try removing the gfo and see if my phosphates come up a bit!

The fish would live more feedings :)

 

[Tired]

Oh, yeah, take the GFO out. You need both nitrates and phosphates solidly present, especially for zoanthids. Make sure you're feeding your fish as much and as often as they'll happily eat, and consider feeding any LPS a bit more.

 

[Pascalereefer]

Oh, yeah, take the GFO out. You need both nitrates and phosphates solidly present, especially for zoanthids. Make sure you're feeding your fish as much and as often as they'll happily eat, and consider feeding any LPS a bit more.

Thanks! I took the GFO out and have recently upped feeding (twice a day). I appreciate this help and will deal with the GHA if I have to :)

 

[Tired]

Sounds like you're on the right track. Get and keep those nutrients up, and you should see happy corals.