Safe Temp Fluctuations for Acropora
 

i've been logging my temperature every few hours for the past few days. there is definitely some temp variation. what is a safe range of fluctuation for acropora to remain healthy?

I get about a 2 degree variance throughout the day and my Acropora are fine and growing like weeds

I start with the tank at 77 first thing in the morning, and by the time my halides are off in the evening, I'm sitting at 80-81. Been like that for the last yrs, still looking good.

do you have captive or collected pieces?

IMO its not the swing, its how slowly the temperature raises and cools during the day. A very fast swing doesn't allow the corals to acclimate gradually to changes while a slower swing, they almost don't know its happening. I did have my tank swing from about 78 to 92 a few days a couple of summers ago (pre chiller) without any side affects. However this does not mean that your tank is safe or you won't experience a problem. A swing of 3-4 degrees seems to be normal for most tanks.

I'm assuming you mean wild colonies and cultured? I have both types in my tank

I vote for how often it fluctuates and how much it fluctuates. I know that when I was keeping SPS in my 20g, having the temp go from 78 at 8am to 86 in by 3pm, browns the SPS right out. They says SPS = stability promotes success... and it's true. I think as long as your temp. is constantly changing , you will have stressed out SPS .. now, if it's only fluctuating a degree or two, it's not so much an issue. I know that when I kept my temps from 78-82 things were alright.. decent colour on the SPS and decent growth, nothing to get excited about , but it was working for me.. that was until we got the hot snaps in the summer time.. going from 78 to 86 every day was just bad on everything in my tank..

HTH.