live rock bleaching

[bjohnston]

I have 250lbs of live rock in a 210 gal. tank. Its been in place 4 months and was doing fine until recently it began to lose all its color turning a milky off white color. Water chemistry test fine. The rock did the same thing when first put in the tank. It recovered over time and regained its color but now seems to be doing it again. Any suggestions?

Sp. Grav. 1.0235
PH 8.2
Alk. normal
NH3/NH4 0
NO2 0
NO3 Approx. 0

900 watts lighting MH+flr.
40 gal. refug. tank
Aqua medic 48in skimmer
25 gal sump
275gal total system

 

[EELectric]

Do regularly add calcium or any other supplement? This might affect the rock. HTH

 

[bjohnston]

I add trace elements weekly and have added some buffering over the last two weeks. I have not added Calcium as it has always measured fairly high at 480 - 500.

 

[Hara]

I think your calcium levels are too high. What is the ALK reading (not "normal", but numbers". The two need to be in balance.

 

[tbonem91]

cant high temps also cause bleaching?

 

[zuzecawi]

When was the last time you changed your bulbs? As in... lighting. Four months... that's about the "good life" for most flourescent tubes. And depending on your halides, that's nearing the useful stretch on some of those. Conversely, if you just upgraded your lighting, the increased intensity can cause your rock to bleach. It's more likely for it to bleach from increased intensity than it is from lessening intensity. Have you recently added or changed out carbon? The sudden clearing of the water clarity with carbon can cause your rock to get shocked by the sudden increase in light.
High calcium dictates having high alk... but doesn't necessarily mean it is high. If you have say, Ca at 500, but alk at 12 dkh, that's too low. I run high Ca, but my alk is a steady 14.5 dkh as well. And I've never had a snow storm, my montiporas and clam grow like crazy, and my corralline has never had bleaching that wasn't linked to too much light too sudden. Also, if you do water changes that drop your water levels, and you have the lights on, you can cause bleaching from light overdose.
What are your nitrate, phosphate, and ammonia readings? Do you dose with iodine or other supplements? What brand salt do you use?

 

[angelscrx]

Is 900w enough lighting for that size tank? Just a question?

 

[bjohnston]

Thanks for the feedback. I do allow the water to drop during water changes with the lights on. I'll stop that practice. The lights are part of the the original set up. They would not be a source of light overdose but may be getting weaker.
I recently changed salt supply from oceanic to instant ocean. Could that be a contributor?

 

[zuzecawi]

Changing over salt really isn't a factor unless you did a 100% water change... and even then, it's more the loss of beneficial bacteria than the salt brand. Well... there are ph and calcium factors, but I've never had any issues do to that, and I did a lot of musical chairs with my tank before I settled on the Pacific brand salt, and the only trouble I had during was the darn $%#$@# Oceanic salt. Melosu must be the only person I hear of who doesn't have long run issues with the Oceanic. (And I suspect her initial water must have a LOT of buffer naturally present )

 

[Hara]

I have been using oceanic since it came out and except for mildly lower ph, I have had no problems with it.

I am still wondering what your ALK readings are.

 

[bjohnston]

My Alk test is a Red Sea multi- test kit that only gives me a color chart that has a low - normal - high color scale. If Alk is the potential problem
I my need to get a different more accurate test. What's a good choice for ALk testing?

 

[Hara]

salifert is always a good brand of testkit...