Not enough/too much light?

[trustmeimalawyer]

Hoping to get some advice on zoa placement. My tank is an 80 gallon shallow (16” tall) lit by 2xRadion XR30 (gen 3 NOT pro) supplemented by T5s. I’ve never had luck with zoas but they seem to be doing slightly better now. I placed a couple frags at the top of one of the structures - the gatorades seem to be doing okay, the purple monsters are slowly melting as well as the utter chaos. I wonder if they are getting too much light? On the other hand, I have some smaller colonies on the bottom sides of the tank that seem to be stretching for light. Pics below. First pic is a full tank shot for a sense of scale. Second pic is the right side of the tank where the melting zoas are mounted. Last two pics are the mini colonies are the bottom sides of the tank (admittedly getting a little shaded). TIA for the advice!

 

[Hydrored]

By the way they are stretching too little light

 

[trustmeimalawyer]

By the way they are stretching too little light

Yes, that’s what I said in the description . Seems odd with a 16” tank and my light set up, hence the question

 

[Hydrored]

Best bet is to borrow a par meter, where my G5’s XR15’s over lap is a par difference of + 30 and zoanthids melt there. To me it looks like bunch of shadowing, par mapping your tank would do wonders. Beautiful tank btw.

 

[danschoenherr]

I don"t always think that stretching means they need more light. Flow does come into play also.
I have nearly the same setup as you , and some will still be stretching even if I move them from the sandbed up 10-12 inches. In my frag tank where I have better control with flow and placement options, I can get the same types to grow closer to the plugs with minimal stretching.

 

[Tonyreeffish]

The zoas in the last pic seem to be doing fine. If youre going to put zoas at the top level of the tank, it's good to slowly step up to it. Start low and slowly move up. You'll find the sweet spot easier that way.