I believe that water changes and fish bio-load are a determining factor in the way things grow and flourish. I do not have a skimmer, I have a built in fuge with macro and three mangroves, my tank runs between 80 and 82 degrees with 1.025 salinity. I do not test for anything and use a two part nano reef dosage every 3 or 4 days. I have only four fish, two shrimp a brittle star and hermits and snails.

Any way, that is my two cents, and again, that is an awesome setup.

P.S

You can see my thirty gallon under '30 Gal. updated W/picts.'

Mine -

Ca = 400 - 420 ppm

 

Mg = 1340 ppm

 

Temp = 77.8 - 80.0

 

SG = 1.0255 very stable

 

And I run carbon and pO4 remover and change the carbon monthly. I Skim fairly agressively, too. I do 18g WCs every 2 weeks, so similar to you but not as frequent. And my fish bioload is similar to yours.

 

Differences : Small - I grow macro, you don't... Bigger - I  have less flow on my return and no CL, so probably only 60% of the gph total flow you have... Biggest - I'm guessing the biggest difference is that you are running 400w MHs while I am running 250w MHs

 

 

 

 

Powderblue tang

2 anthias

percula

2 chromis

mandarin.

I run SeaGel (activated carbon and phosguard) through a media reactor.  Run a Euro-reef skimmer rated for roughly 180 gallon.  UV sterilizer.

Salinity 1.026

 

ALK min 8  (i let it go down to 8 with salifert tests, then over three/four days i raise it to 9.5ish)

 

Calcium  min 400 (after alk is raised up i wait a day then dose with Reef Complete till calcium is up to 450ish)

Then wait a day and dose Magnesium if needed. then start cycle over

TEMP 78-79 (one week ago i added another 250 DE 20k to my 400w ushio 14k's so temps are now at 79-81)

 

Try and do a 15-20 gallonwater change with reefcrystals every 5-7 days. Besides that I have a fair amount of flow with a closed loop on an iwaki 30md and return with an iwaki 40xlrt on seaswirls, and 2 MJ 1200 modded for more flow. 

 

I don't grow any macroalgae for nutrient export.

 

Sand Bed 3+ inches.

 

Tank Problems:  Besides all the great SPS color and growth I have gotten on my tank there are three out of about 40 pieces of SPS that don't do well in my tank.  One is a garf bonsai.  I have two different frags of this species and one has grown and kept color and the other has encrusted yet never gotten its purple color back on the stalks.  Some other coral that I got from Jared awhile back slowly lost its color but still has grown.  A random bali maricultured that is finally getting color after being brown for four months. (my friend has this piece as well and his is doing the same browning except for the tips).  Also my green slimer has never gotten that deep green color that its known for, but it grows like a weed in my tank.  Besides that doing good.

 

I don't know, i really think just constant maintenance and slow and steady parameters are my success. That and luck.

 

What do feel is your "secret" on the SPS growth?

 

My own small SPS frags have all colored up very nicely and display great extension... but to my eye have not actually grown all that much...