Real reason why my zoanthids are doing good?

[drivingmecrazy]

I have roughly about 70 different species of zoanthids. I have each of them in all three aquariums. In case something happened to one particular Colony or frag I have a backup in another Aquarium.[emoji4]

Out of all three aquariums, my Zoanthids tend to grow better in this one particular aquarium.

All lighting and equipment are exactly the same.
I test my water using salifert test kits.

Everything is exactly the same except this tank seems to keep a constant iodide level at >.01

And I also have phosphates in this aquarium. .025. Enough to grow brown stringy algae.

The other two aquariums I use gfo with zero phosphate levels and all three aquariums has zero nitrates. However, for these particular two aquariums I have to constantly dose iodide and every three days it's undetectable. Zoanthids are thriving just not growing as fast.

I want to start using GFO on the tank that the zoanthids are doing great in. I'm afraid though that if I start my zoanthids may not like it.

So I'm thinking...

I may run a little GFO, enough to bring the phosphates down to .o1
And keep my iodide level the same.

Out of the two what do you think is the real reason why the zoanthids are doing better?

Phosphates or iodide, or both?

Thank you,

Christopher

 

[Muttley000]

Interesting experiment! Phosphates is my guess.

 

[titlowda]

I have not had luck running gfo with zoas. Ymmv