What am I missing?
 

Hi everyone, I need serious help.
I have a 20 gallon tank, 24 x 18 x 12
No matter what I do, none of my coral I have is very healthy. I use RO water when doing water changes. I feed the tank with Marine snow and Seachem reef plankton once a week. I use Aquavitro Fuel twice a week, (Mondays and thursdays). I have a lumentek 120 light over the tank, about 9 inches up, maxes at 40 on blues and 15 on whites. I have one jebao wp 10, and a fuval sea nano Powerhead. My parameters are as follows.

pH 8.0
Nitrates <5
Nitrites 0
Carbonate Hardness 8 dKh
Calcium 480
Magnesium 1460
Ammonia 0
Phosphate <0.1

What can possibly be the problem? Too much flow? Not enough light? I haven't had any growth whatsoever in the past year. None of my LPS are growing in any way. When the acans I have start to open and grow, they end up just detaching from the skeleton and dying. It makes no sense!

How often do you do water changes and what salt? Also what is the age of the tank? And your salinity, top off schedule?

Every two weeks, red sea coral pro salt. Tank has been setup for a year and a half or so.

Do you have an automatic top off? If not how much evaporation are you getting and how often do you top off? What is your salinity and how do you measure it?

pictures might help

Salinity? Tank inhabitants? Temp?

Two clowns and a six line Wrasse. Salinity is 1.025 temp is 78

I use a refractometer to measure it, and I calibrate it every water change

What corals?

What kind of flow units?

It can be really easy to add too much flown a 20 gallon if you have a hang on back filter it's probably even enough

http://www.amazon.com/Jebao-WP-10-Aq.../dp/B00INTDJLC

and

http://www.amazon.com/Fluval-Sea-Cir...sin=B009XSGI3S

various euphyllia, acans, favia, many zoas, and a few shrooms

When you say "not healthy" what do you mean? Slow to grow? Pale? STN?

On a side note, you don't need to calibrate your refractometer each time if you don't want. I do mine every few months and it's always stable. If yours keeps drifting, you might want to consider an upgrade to a better quality one.

Pictures?

+1, I run a calibration lab at an Aerospace company, all of our refractometers are calibrated annually. .08% come back out of tolerance.

They are very reliable, if you havent dropped it, calibrating every 6 months is more than enough.

There's a big difference in what I assume is lab grade equipment that you have there and a $30 brine refractometer with a cheap screw adjustment that most people in the hobby get.

I had a few of those cheap ones that needed constant adjustment. I finally bought a vital sine which was around $100 and is very stable. I still check it against a reference solution monthly but rarely do I have to adjust anything.

http://postimg.org/image/nkefy80yd/
http://postimg.org/image/tgmv7s1cf/


First is settings on my light. Second is a hammer coral, and my favia. The favia had skeleton shown when I bought it, but I think the flesh is slowly receding.

I would start with lowering the flow, take out the nano powerhead and run the Jebao on the lowest setting. I also wouldn't dose anything except alk,Cal and mag (if needed). keep it simple, maybe turn the whites up a little to maybe 20 then 25 just do it slowly.

So any changes?