Question regarding SPS coloration

[trameaa]

I could really use some help from the experienced SPS guys...
I've been keeping my reef tank for about 3 years now.
The aquarium is around 40 gallons, but a bit odd sized (12" tall), and I have a 30 gallon sump. There's about 60-75lbs of live rock in the display, and I'm running a Euro Reef skimmer and ReefKeeper Elite controller. Lighting consists of a 6x39W T5 Tek Light which is about 6 inches off the top of the tank.
I'm also running an MR1 with GFO pellets from BRS.
For flow, I'm using one Vortech MP10W ES, one Hydor Koralia 1, and my return pump is pushing 500 gph (Mag 5).
My water chemistry seems to be ok - I've been tracking it and documenting.

Most recent tests showed -
Salinity 35 ppt - refractometer
Temp - 78 (night) - 80 (day)
pH 8.15 (night) - 8.34 (day) - Reefkeeper and Milwaukee
Alk ~10 dkh - Salifert
Calc ~ 430 - Salifert
Mg ~1300 - Salifert
PO4 - 0.021 - Hanna ULR
N - undetectable on my test kits (cheap kit, maybe API )
Because there is algae in my tank (several kinds), and chaeto in my sump continues to grow, I assume that is an indicator of nutrients in the water - therefore I do run GFO and carbon on the system 24/7.

I have had great success with fish, _most_ soft corals, LPS, and a bubble tip anemone (xenia, toadstool leather, kenya tree, GSP, frogspawn).

SPS, not so much....
Every piece of SPS I put in the tank turns very pale, bordering on white (but not quite, we'll call it white with just a faint hint of some color)
The polyp extension is excellent, and I get great growth, but I'm just growing more or less white sticks with polyps.
The corals don't brown out either, they always go first to pastel colored, then even more white over time, though they continue to encrust and grow.
To be honest, I just can't figure out what I'm doing wrong.
All the filters in my RODI were replaced last month, along with the DI resins - I even installed a booster pump thinking that pollutants might be in the source water if the membrane wasn't operating at maximum efficiency.
I don't regret the purchase because making water is certainly much faster now.

The thing I keep coming back to is the lighting.
Because the corals are turning pale, not getting brown, I'm thinking that 6x39W T5 lamps might just be too much on a 12" deep tank.
I don't know, but it sure would be nice to figure this out so I can start enjoying the hobby again.

Any ideas??

Thanks everyone! :hmm5:

 

[lolgranny]

When you put your corals in your tank and you acclimating them to your light? It sounds like your shocking them which makes them loose their color and turn white / pale. If i were you i would either take them and place them in the sand or higher your light. I take about a month before i put my corals on the rock so they get use to my lighting. I would put all my chips on this being the issue. Your basically bleaching them out. The color will come back in time, but they will turn green before anything.

 

[Iskandar]

they need a bit of nitrates to color up.

 

[Reef Bass]

FYI, N is the symbol for nitrogen, which is not commonly tested for in reef aquaria. Nitrite is NO2 and nitrate NO3. I assume you were discussing nitrates.

I'd measure the par in your tank but I doubt it's too much on an absolute basis. I run 6 54w t5s over my 12" deep tank no problem at all.

To me it sounds as though you are bleaching the frags. Did they come from a lower par or lower alk environment?

 

[trameaa]

All very good points and thanks!
Reef - yes, I meant Nitrate, appreciate the correction. You'd think I would know that by now, but Nitrate is one thing I've never had any issues with and I don't test for it often at all. Quite frankly, I've never gotten a detectable nitrate reading except maybe in the very beginning - on any test kit.

The place I got the frags from was running a T5 setup also, but his system was over 40 inches deep, and the corals were probably mid way down the tank.

For starters I think I'll feed more often since I'm running carbon, GFO, and skimmer 24/7.

 

[Reef Bass]

The place I got the frags from was running a T5 setup also, but his system was over 40 inches deep, and the corals were probably mid way down the tank.

That's the issue. Your tank is not too bright on an absolute basis, but being only 12" deep is brighter compared to where the frags originated. The frags bleached as a result. Bottom of the tank for them for now. Maybe some screening on top, maybe raise the lights.

They will most likely brown first as they repopulate zooxanthellae and then, assuming the environment supports it, develop lovely color.

 

[lolgranny]

That's the issue. The frags bleached as a result. Bottom of the tank for them for now. Maybe some screening on top, maybe raise the lights.

Oi Just as i said! You didnt acclimate them and shocked them to the white state they are in now. Put them on the sandbed and give them some months to color back up.