Stubborn Cyano

[cdearing]

Do you use a skimmer? Hopefully you do. I agree that the first thing is to stop using tap water. If you aren't testing it then you have no idea what is in it and it could kill fickle creatures. I would never turn the lights out on the tank for any length of time except for your normal light cycle to try and hamper cyano growth. You could harm your other inhabitants by doing so. You could also try blowing off your live rock with a turkey baster to get the detritus into the water column and hopefully into your skimmer. I have had a couple of problems with cyano but mine was attributed to a cycle when my tank was fairly new. I also painstakingly would clean it off the sand and rocks with either a syphon while doing water changes or actually sucking it off the rocks with a turkey baster. Don't give up. Just keep working on it. You will eventually get it under control.

 

[NC2WA]

Somethings Fishy,

I have used this product once, and it did work, but IMO it is just putting a band-aid on cancer.

It would be better to find the root cause of your cyano and treat it instead. otherwise, you will be fighting cyano for some time.