Disaster!
 

Okay so stupid me did a water change yesterday and the water level in the tank went down almost half way exposing some of my corals mainly my SPS. I Left 2 super blue T5 bulbs on so I can see. Didn't think it would be a problem because they werent going to be exposed very long but then I started smelling something really stinky and my monti colony looked kinda dry so I refilled the tank as quickly as I could and turned the lights off.

Today when I turn on the lights my monti tip especially the top was whitish and my red digi colony top branches were whitish and polyps not out like normal the bottom part seem okay polyps still out. Green bird nest polyps not fully out like usual and whitish. Even my lps hammer , frogspawn, octospawn not fully open like usual. everything else seems ok zoas, other softies some lps.

Is there anything I can do should I leave the main lights off for a few days?
Really sad my red digi colony was growing so nicely really don't wanna lose it. :cry:

On a good note though, I think my rbta split into 3!!! On the same night... Strange

I'd suspect water before being dry. All my corals are exposed for 15 minutes under full lighting every 2 weeks without issue. Wild corals are often exposed to full sun during low tide, no problems.

This in particular tells me that the new water was a problem, anemones will often split with drastic changes. If you have enough of the new water left in the tub, I'd test it for alk levels. Or, did you use a new salt? Anything else different?

That's what I thought... I think it might have been longer than 15 min though maybe 30-45...

No nothing really different... Same salt I use io. I did dose my tank with chemi-clean maybe couple weeks ago did the water change like the instructions said but my skimmer was still acting crazy so I left it off. Corals were looking awesome still. didn't get to do a water change again till yesterday and I did 5g more to hopefully get my skimmer back online do u think it could be that?

I bought a large stag acro and it was too large to pack. I moved it to my house dry in a rubbermaid tub. I was probably out of water 70 or 80 minutes. No issues. I once burned the tips of a coral under a 400w bulb by leaving the water low for 30 minutes, but that's an extreme. Your lighting shouldn't cause any issues like you describe. Worst case, you could get a lot of slime, but no losses.

+1

Probably 1/3 of my acropora are fully exposed when I do water changes on my tank and they are sitting only 10" under 12 x 80 watt T5 tubes that I leave on so I can see what I'm doing. Most of the time they are out of the water for 30 mintues by the time I fininsh refilling the tank and sump and I've never experienced any losses from this.

I'd have to agree that likely one of the parameters in you new water was off and alkalinity is commonly the cuprit. Too high mag levels can also cause problems but you usually don't see high magnesium in any of the comercially available salts.

I don't think it was the exposition to air as well. I take a long time to do my water change because I refill with bucket from my basement so it takes me 40 minutes minimum and during this time I shut down my heater (to prevent overheating and cracking) and I leave the T5 on.

I never had a problem with any of my SPS doing this. It does smell very strong, and they often produce mucus but they are just fine one hour later.

Ahhhhh I think you guys are right! It made me think that though because only the top of the sps's branches were losing color not the bottom part or the top heads of my frogspawn. The part closest to the light.

Anyways I think I found the culprit. :twised: I tested the tds of my ro and it was 17!!! Omg I guess my membrane is finally done cuz I replaced all the other filters like a week ago! Argh I'm so mad.

How bad is this? Going to replace the membrane today. Should I do a large water change after I make new water? How much should I do? My tank volume is roughly 40 g I think.

My Sps and lps were looking better today though sigh...

Lots of people use tap water with much higher TDS, I don't think that is the issue.

whats your alk?