Coral only tanks

For those of you who have coral only tanks. How often do you do a water change?

I put up a 20 gallon long nano for my LPS & SPS corals from my 75 gal, that has been taken over by bubble algae and wacky water parameters.

Funny, when I had my 10 gallon mixed reef nano back in 2007 to 2010, all the corals grew fast and were very healthy. The coraline algae was all over the tank. People told me that going bigger would be easier and more stable. In my experience with going bigger, nothing could be further from the truth. My 75 never looked anywhere near as healthy, awe inspiring with color and coral growth, as my nano did.

 

When I was fish less (bio cube 14) I changed water once a month, to make up for the lack of fish poop, I fed the corals more often.

I will say I've had much more luck in my 34g vs. my 14g.

 

My last tank was a 28 with one fish, a monthly water change. This tank has two fish, still a monthly change. As long as your topping off and dosing as appropriate on a coral only tank every 2-3 months should be fine at the least, monthly if you are concerned about replacing trace elements such as Iodine and Strontium.