Pale Coral Problem

[Willy Honeycutt]

Hey, everybody. So I've had a 55 gallon reef tank running for about 8 months, and most of my corals are all a pale purple/pink color. All of them are growing and seem to do fairly well, but they're all the same color. When I added each one, they lose their original color and match the rest. The corals that have this color are: Nepthea, kenya tree, unknown leather, taro tree, yellow sinularia, xenia, pulsing xenia, and a torch coral. The corals that seemed to have kept their original colors are: montipora, zoanthids, palythoa, mushrooms, ricordea, and green star polyps.

Here's a little bit about the tank: 55 gallons with 20 gallon sump, 4 T5 54W bulbs (Geisemann Aquablue Coral), chaetomorpha refugium with 100W plant grow bulb, reef octopus protein skimmer, regularly changed activated carbon in reactor, 9 hour photo-period, and stocked with a yellow tang, a blue chromis, and a starry blenny.

Parameters Tested:
Salinity: 1.025 SG
Calcium: 530-600 ppm (I'll explain)
Alkalinity: 8 dkh

I used DIY live rock consisting of oyster shells, sand, and portland cement. I cured then in circulating freshwater to try and leach out the products of the cement curing, then cycled them for several months in saltwater. I still suspect they are leaching a large amount of calcium, because the levels are really high without dosing, and I have to dose sodium bicarbonate to maintain alkalinity.

I have three idea of why the corals may be pale:
-too much light, the T5's are only two inches off the surface and on a narrow tank, with some corals close to the light.
-Nutrients too low: I don't have a reliable test kit for nitrate/phosphate, but I have no algae growth, I don't feed much, and a good refugium.
-High calcium / contaminates from DIY live rock.

Here are some pictures. Any input from experienced reefers would be appreciated.

 

[Purplelobst92]

probably nutrient related, throw in some more fish, or perhaps feed every other day via broadcasting reef food. you have so much nutrient export that your tank is probably just too clean.