Metal halide and zoas???

[Axolotl]

Got two 400 watt mh about 28 inches from the the bottom of my 75 gallon reef tank. Would the zoas even open up? Too much light? Screen them for couple days? Never kept them before. I have leathers xenia anthelia and gsp in there and they are thriving. Just always heard the zoas liked less light like mushrooms...

 

[A. Grandis]

Well, well, well…
It depends, I would say.

Why are you keeping the 75gal under 2 X 400MHs?
What brand/K are those MHs?
What is the MHs photoperiod?
Any supplemental lights? What type?
If so, what is the photoperiod for the supplemental lights?

Grandis.

 

[Axolotl]

Hi. No supplemental. They are on for 8 hrs. They say 20k but are cheap off brand in retro reflectors. Looks more like 10k. There are xenia cuttings on the bottoms on lr rubble that sometimes shrink and close up because its too bright i think. But the xenia up top thrive. Im thinking this is because they are cuttings thus new growth like babies? Idk.

 

[A. Grandis]

If you adapt the zoas carefully they will morph and get used to the light.
You can actually bring the photoperiod down to 6 house a day.
I just think it's a waste of money to have that much light over a 75gal.

Grandis.

 

[charliet21]

I run 2x 150s over a 55g and only run them 3hrs a day.. tank is mainly z/ps but is a mixed reef

 

[charliet21]

I would center one of the 400s and take the other down and raise the centered one up for more coverage..

 

[rogergolf66]

i would center one of the 400s and take the other down and raise the centered one up for more coverage..

+1

 

[eg8r210]

Two 400w MH and not a single mention of SPS? I am confused but agree, based on what I see, you are spending a lot of money on electricity that doesn't have to happen.

Without supplemental lighting and a light that you proclaim looks more like 10k, I don't think you are going to get the pop of color in the zoas but for sure you should be able to keep some with no problem. Some zoa like a ton of light, others don't. Some morph into a different looking polyp with a ton of light, and others don't. No matter what, I would start them out at the bottom of the tank and off to the side or in some shade if possible and see what happens.