Bubble algae issues

[TanksNStuff]

Yea, I was going to say keep an eye on the ALK. As Pete said, higher ALK in your salt wouldn't be as detrimental in your big tank as it would be in the nano. I would suggest testing the new salt water before doing a WC to see how high it is.

Acans can be finicky in general though. Once they start to go, they are hard to get to recover. It could have just been something minor that irritated one head, and that spread to the rest of the colony.

 

[NikkiT]

My money is on the sandbed. I would imagine that the sand was absorbing nutrients during the time when WC were 1x per month, and with it being disturbed, the nutrients were released into the water. It could be as simple as the pistol getting into a particularly nasty part of the sand bed.

I have kept nanos for a long time, doing 15-25% water changes regularly over most of that time period. I don't think you are doing too big of a water change. My nanos with SPS LOVED frequent water changes.

I agree with George that the problem could be your makeup water having different test parameters than your nano. Swings in nanos happen fast, and if your makeup water for example has low dKH, that could be part of the problem- the coral is weakened by the ammonia released from the sand bed, and then the change in dKH, temp, whatever is the end of it.

 

[Hockeynut]

I agree with Nikki, I just took all of the sand out of my sons 20 which had been running for a couple years coupled with a big water change and the tank looks great. You should have seen what came out of that sand Nasty!!! If your not ready for the upgrade just ditch the sand. I think that if you have a tank with sand you have to change it at some point.
I also change 5 gallons a week in a 20 with no sump and lots of rock so I'm well over a quarter of total volume a week.