SPS Corals - color?

[MagicMan]

My two hard corals seem to be growing, slowly, but the pink one is no longer pink. It is now a dull off-white. Don't know if it died, kind of looks like it but it appears to be growing. The yellow one is definitely growing, but color is also fading.

General question: What do I need to be doing in my tank to keep hard corals alive and well and colorful?

I've already got good light. All of my refills for evaporation is kalkwasser. I add 1 ml of Reef Iodine and Reef Strontium every other day (when I feed the tank), together with some Kent's Tech-M.

I've been feeding the tank a cube of formula food's Prime Reef as well.

[MiddletonMark]

Can you tell me about:
the lights
the skimmer
what else is in there [corals/fish]
what any recent water tests were?

Have a photo of the corals? Know the Genus name? Common name? I have guesses based on your description, but it's hard to be sure.

20 questions, I know ... but likely it's either not enough light, too many nutrients, not enough flow ... or just that coral itself.

[MagicMan]

Lights - two banks, four total bulbs, VHO, 2 say white-actinic, 2 say super actinic.
Skimmer - protein skimmer. Let me know if you need the make.
Tests - Salt (1.024); Nitrite, Nitrate, and Ammonia (nothing measurable); ph (8.4)

Other wildlife - Button Polyp, derasa clam, bubble-tip anemone, clownfish, 6-line wrasse, green mandarin, green brittle star, 8 - 10 turbo snails, 25 hermit crabs, 2 veiled limpits, LS, LR

I don't mind the return questions. I am extremely motivated to have a great and healthy tank. I just appreciate your response.

[SouthernReefer]

can you test for phosphate?
for sps corals you want optimum stable water parameters; 0 phos/nitrite/nitrate, calcium at 400~450ppm, ph at 8.3, alk 8~12. strontium 10~12, o2 at 7ppm, temp 76~80'f, high water flow, ect.....
hth!

[ruhspolostar]

VHO's usually won't provide enough lite for SPS unless they are placed VERY high in the tank

...but thats just from my experience

[MiddletonMark]

Yep, I would also agree with the `less than 8" from the water surface' for VHO's + SPS. The can color up well, but you're at the edge of enough light, so make sure they're getting good flow and water conditions are good.

[Superfly]

Very likely a lighting problem. Are you testing your calcium/alkalinity levels? SPS need consitently high levels of these to thrive. Fading color is often indicative of a lighting problem though.

FWIW, you CAN keep SPS with your light, but you do need to be careful about what species you have and where they're placed in the tank. I have several Montipora and even a Lime-Green Acropora thriving under normal output fluorescent lights, but many other SPS would not even live under this lighting.
HTH,
Superfly

[MagicMan]

They are placed about three inches below the surface which is about three and a half inches from the light. Maybe four inches at the most.

I will check water for the matters SouthernReefer raised. I really appreciate the numbers, that will be a big help.