Zoas not growing at all

[HerthaYid]

So i've had these green zoas for around 6 months now, and they have not grown at all, if anything they have got smaller and a couple smaller heads have died. The orange ones are new since yesterday, so this is only regarding the green ones. I have pulsing xenia which is really growing quite fast. I also have GSP which is growing slowly, and had some Tricolour Clavularia which was growing at a nice rate until it dissapeared (think my Tuxedo Urchin got it).

My current levels are as below:

PH - 7.47
Ammonia - 0
Calcium - 470
Magnesium - 1500
Nitrate - 2.6
Nitrite - 0
Phosphate - 0.05
Salinity - 1.025
Temperature - 24.6c

I had a cyano problem for quite a while which I couldn't fix, so i used chemiclean as a last resort which got rid of it, and its not been back since. However since then, a bubble algae outbreak has occurred which has become quite severe. I currently have 3 emerald crabs battling that. My nitrates have often read 0 in the past, so i tried to up the feeding but i feel that is just fueling the algae. Is it a case of the algae consuming all of the nutrients instead of the corals?

I have a chaeto refugium in the sump as i wanted to build up a healthy copepod population so i could get a mandarin fish. Do you think that maybe I did this too early, as the nutrients are already too low? I currently feed a small pinch of flakes in the morning, and half a cube of mysis or brine shrimp in the evening. The tank population is as below:

2 x Clownfish
1 x Firefish goby
1 x Peach fairy basslet
6 x Blue green chromis
1 x Cleaner shrimp
1 x Tuxedo urchin
1 x Luzon sea star
3 x Emerald Crabs

and a bunch of hermits, various snails etc in the clean up crew

I also had a candy cane coral that died after a month or 2, the flesh just slowly melted away. I had a hammer that never grew and eventually the polyps bailed. I can't pinpoint what is wrong in my tank. I dose phytoplankton 1-2 times a week. Last month i started dosing zooplankton once a week, and have just started using reef roids this week to see if that helps the zoas grow.

 

[Mr. Mojo Rising]

To me, withering away slowly over 1-2 months is usually a lack of light. I don't see anything in your parameters that will slowly kill the corals.

what kind of light and what intensity and how many hours per day do they run?

Do you use rodi water?

 

[HerthaYid]

To me, withering away slowly over 1-2 months is usually a lack of light. I don't see anything in your parameters that will slowly kill the corals.

what kind of light and what intensity and how many hours per day do they run?

Do you use rodi water?

I use the AI preset from David Saxby

https://www.aquaillumination.com/signature_series/david-saxby
The lights I have are 2 x Hydra 32’s

Yes I use RODI water too