Okay, So I've been going roughly six weeks doing this same thing. And my results have been quite interesting.
First, possibly due to "overskimming" one could say I'm running an "Ultra Low Nutrient System". I think the lack of nitrates/phosphates as I've indicated before show this to possibly be true.
Additionally, I found a couple threads over on reef central about this:
Calcium/Alkalinity & PH, SPS color... - Reef Central Online Community
The Dirty SPS Tank Club - Reef Central Online Community
TL;DR on those threads, a.) high alk
in low nutrient systems can be stressful. b.) Low nutrients == no food for corals
So here's what I've done:
1.) Back off my ALK
down to between 7-8.
2.) Kept calcium around 420 or so
I did a 5 gallon water change on 27 FEB, then again on 27 March.
1.) 1/3 cube of Marine Cuisine frozen once a day, at the same time, I target feed all of my corals with Reef Chili from BRS. (fwiw, I do two scoops, which is 2x the recommended dose of what one should do every 2 or 3 days)
2.) Once a day when the daylights are off and tentacles are out, I'll drop in 5cc of phytoplankton or thawed cyclops in the current and let the tank feed itself.
Significantly better growth and colors have improved dramatically. In the last 6 weeks, once acropora has encrusted appx 1cm on the rock it is on and it has gone from a "blah" brown on its tips to a really nice blue.
Nitrates & Phosphates are still not detectable.
I am pretty sure my city water contains chloramines, so I was adding some prime to my RO
top off water. Well, that was stupid, since it caused most of my Chaeto to die off....that was a two week or so experiment, so the remaining chaeto is coming back.
I have two tanks that have been in the same situation, both about 23-24 gallons of water volume. About 3-4 weeks ago in my nano cube, I was trying to rescue a new ric from my pistol shrimp when I knocked my T5 fixture into the water...and my arm was in the tank. Luckly, I was wearing rubber gloves up to my armpit, and my wall plug tripped. Nothing died (including me), so move on and be thankful.
Anyway, I borrowed a RapidLED Onyx (I had a 4 bulb T5 fixture), and the changes have been even more astounding. Check this out:
A wild acro that didn't do to well for me. This is one (of the many) pieces I was able to save. Colors are terrible, right?
It was really starting to color up nicely with this experiment, but the LEDs over the last 3 weeks have made a huge difference. I'm just shocked, honestly. (the one on the left). It was beat up by a mili on the frag rack a couple weeks ago, but it is coming back nicely.
Here's a FTS. I need to rearrange so the red brain doesn't fight with the hammer.
So I guess so far this has worked really well for me. I'm going to go back to 5 gallon water changes every two weeks, I think. Other than that, I might look into LEDs again for my small shallow tank. I'm really shocked at the amazing results over the last three weeks in my nanocube