Excess Cheato growth; lightening corals

[Pacman100]

I have some cheatomorpha in my sump that grows incredibly fast. A softball size clump can turn into a fairly solid 18"x18" mass in 2-3 weeks. This seems good in some ways: nitrates have always been unmeasurably low. I have never had a problem with excess HA or other problem algae.

Unfortunately is seems that a lot of the corals in my tank gradually lighten up over time. They seem healthy and are actively growing, but I am wondering if there simply aren't enough nutrients to feed the zooxanthellae very well. In some cases (alveopora), the corals almost seem to lighten up so much they gradually turn white.

I used to also have some red macro algae and Halmidea that grew in the tank, but their growth seems to have stagnated. I believe there simply aren't enough nutrients for them.

I've got a descent fish bioload and have been feeding pretty heavily for the last month to see if any coloration came back to the corals. It only seemed to make the cheato grow faster.

So...should I pull the cheato? If so, how should I do it?

[graveyardworm]

We're gonna need more info. Tank description, feeding, lighting, livestock. Most corals are well adapted to live in a low nutrient environment, and with the rapid cheato growth you describe it would seem that there are ample nutrients to go around.

[Pacman100]

Oops, thought I had filled out my sig line...

It's a 45 gallon breeder with 375 watts of VHO lighting. Been set up for over a year, have been gradually stocking with mostly LPS/Softie corals. It has a AquaC Urchin skimmer. Fish are 1 dispar anthias, 2 ocellaris clowns, 1 sixline wrasse, 1 purple firefish, and are fed a varied frozen diet (shrimp, krill, spirulina, more I don't remember off the top of my head). I use B-Ionic to maintain Ca/dKH @ 420/9.0.

I do have a few montipora sp. in the tank that are growing well and have not lightened up. It is mostly the LPS corals that have lightened. It's not that I feel I don't have nutrients, just that the cheato is outcompeting the corals. Is that a possibility?

[graveyardworm]

If the cheato is growing well than my guess is there are enough nutrients. I hear the word outcompeting used alot but cant for the life figure out exactly how that might work. The nutrients are either in the water column or they're not, and if the cheato has access to them then so dont the corals until they're gone, and if the cheato is continuously growing then nutrients are continuously available to all.

That's about as far my knowledge can go to explain it.

That sounds like alot of light for a 45 breeder. How deep is the tank, and does it have a sand bed?

What about water changes and magnesium? How often do you do a water change and how much, and whats the Mg level? Perhaps there are other elements which are becoming limited.

Edit: You could try keeping the cheato pruned more so that it doesnt have quite so much nutrient absorbing mass maybe the size of a baseball.

[Brock Fluharty]

Breeders are generally much shallwer than regular tanks, so all that light is proably bleaching them out...

[Pacman100]

Yeah, I was thinking there might be too much light in some ways. Hmm, now that you mention it the blasto is looking a little lighter on the top than the sides. Ill see what I can do to decrease the amount of light getting into the tank I guess.

And, I think I'll go ahead and keep my algae pruned a bit more. The LFS gave me a good amount of store credit for the last 3 gallon bag I brought in. I guess I can just keep my addiction going that way!

[Cubman777]

If your LPS are turning white, and your SPS are not, then I can almost guarantee that the problem is too much light. 375 watts is a lot on a 45g breeder