Dosing for coral growth

[Coleus]

I am pretty sure that all my corals are growing very slowly comparing to other reefer that i know

Here is my tank params ( very stable for last 6 months)

Mg 1350
Calc 420
Alk 8

Nitrate: 0 (test with API)
PH: 7.7 to 8.1

I have 3x250w MH and 4x39W T5. I run bio pellets and carbon reactors. Using two part dosing. I feed my fishes 4 time per day and my coral on M-W-F with BRS Reef Chili Coral Food and Brightwell Aquatics Zooplanktos

But for some reason which i can't explain, my corals are not growing at all, the only things that actually grow in my tank are fishes and anemones. I have both lps and sps but none of them seem to grow


So i am thinking of dosing zeovit coral snow + amino acid + zeovit food, will this do the job?

Thanks