Lighting question.

[LostMind]

I have 2 x 250w MH and 2 x 60w actinic now. My friend has his tank with 2 x 400W MH and 2 X 96W actinic. We both picked up a frag of the same stuff (montipora digitata) and within a week or so, our frags look different.

His has turned more blue-ish in colour and his polyps stay really close to the skeleton of the coral.

Mine has stayed brown but the polyps in mine are extended twice as far out.

Being very new to corals, I am unsure which one is healthier? I like his colouring and like my polyp extension...

The blue-ish tint - is this due to the higher intensity lighting? If so, what suggestions can anyone make for upgrading my lighting besides just going and grabbing a set of dual 400W :)

Would adding some T5 strips to my setup make any difference? Increasing my actinic supplementation?

[Jack]

What kelvin are the bulbs? This sometimes plays a role in coral colouration.

I think the reccessed poylps are just due to the really strong 400w lighting. Montipora Digitata aren't light demanding SPS corals. Also the poylps retract a bit if it's put under really stong current, in my experience.

A lot of factors play a part in coral pigmentation, every tank is different. Both corals sound healthy though.

HTH a bit.

[StirCrazy]

T5's are not going to increase the intensity over what you have. look at types of bulbs and how high above the water they are. also there are various other factors that play in coral coleration, what are you water peramitors, how much water flow do you have.

I have found that in my tank an higher ALK brings out more color in some corals.

Steve

[robbyville]

Adding to what everyone else has mentioned, is that initial coloration can somewhat depend on what the lighting was like on the previous tank that the frags came from.

For instance, J&L has most of their SPS stock under 400w bulbs, they have always told me that coloration might change at first when I put new stock under my 250's. However after a period of time the corals should acclimate and coloration will build up beyond the brownish color. Of course this is only part of the color scheme!

Best,

Rob

[Son Of Skyline]

Sounds like a lighting issue. I have brown montipora in a few places in my tank. In high light areas, the polyps are always half receded and the skeleton has a purple tinge to it. In the shaded areas my monti have more polyp extension and are solid brown.

[LostMind]

Tank parameters?

amm, trites and trates for both tanks are 0,0,0.
ph in mine is lower, 7.9 his is 8.1 (he has more hair alage)
calcium is 440 in my tank, 390 in his
alk is 13.5 in mine, 11.4 in his
salinity is at 1.026 for both
temp around 81 for me, 79 for him.

In terms of flow, I have roughly double the flow he has, but most of my flow comes from my pumps and get pushed thru my sqwd for wave action, he has 4 powerheads dropped in his tank.

My lighting is using 250w 10,000k Ushio bulbs. I beleive his are also 10,000k ushio bulbs, just 400w.

I am wondering... polyps are for feeding, right? So... if the coral is receiving a higher intensity light, it's food requirements will be met more readily via photosynthesis, right? So, in a lower light area, the polyps might be out more in search of more food?

[Jack]

No offense, but this is Digitata, very easy SPS coral to keep, you're worring to much :mrgreen: Both corals you are describing are heathly, the colours just depend on different lighting intensity's, youre parameters are great!

[LostMind]

hehehe, but we both want a PURPLE one with fully extended polyps :)

We got only half of that each!!

And yeah, I picked these frags because our tanks are quite new and this is our first corals, period. Well, I also have some zoo's now as well...