Why aren't my corals growing?

In a long established tank, I have hammers, torches, leathers, an acan , a Duncan, zoos and a blasto. All of them purchased as frags and all seem very happy, yet very few seem to be growing to any degree. All are being target feed with a variety of food 2-3 times a week. My parameters are

Alk at 148ppm or 8.28 dKH
Calcium 485pp
Mag 990
Ph is 8.3
Nitrates and Phospates are zero
Salinity is 1.025

I started adding a Red Sea Mag powder additive yesterday to elevate it and realize that my Alk is a bit high. Is there something I'm missing?????

 

perhaps your water is a bit "too clean" for the corals.....you want a little nitrate and phosphate for the types of corals you're keeping

 

Just feed the fish and corals more often would do it ?

 

it might

 

Anyone else have a suggestion?

 

Your alk isn't high at all but your magnesium is way low unless I'm reading it wrong. I keep my alk at 10 and mag around 1350-1400.

 

I would definitely re-check that mag value. Ca/Alk seem in line which is odd with such a low Magnesium.

What is your lighting type?

 

I re checked it and apparently screwed up the test yesterday. I just retested it and Mg is at 1470. I'm running 3 250w MH and the old T5 fixture was refitted with 2 six foot long Reefbuilders blue LEDs. Unless my tank is too clean as was suggested earlier, I am at a loss why these corals are not growing......

 

I stare at my corals to make them grow

 

If you have good coloration than I an not inclined not to be concerned regarding starvation but you can definitely see if feeding your fish more helps as long as you do not see the development of algae. Might try some ReefChili, or similar products, all my corals loved Rod's Foods.

Takes some images wait a month and take images of the same corals, and compare growth, you might not be seeing the actual rate because you see the corals all day every day.

There will be times when your corals get dialed in and you will notice growth spurts, it's a lucky few that can maintain that growth as a constant.

Your lighting sounds awesome, it should more than do the job.