No, stopping the use of tap water will not make it go away. But you will no longer be feeding it either. We're going to have to work on getting rid of it. It will take work! It will take time! Most of all it will take PATIENCE! It didn't happen over night and sadly your the one left cleaning it up. I feel for you

I'm going to assume that this is a 29g bio-cube correct? An all-in-one tank? Chamber in the back? Go to your LFS and buy a bag of Purigen. (Better yet is Blue Life Clear Fx Pro which is sold via one of our sponsors JimsReef.com) This is a phosphate remover, add this to your first chamber. Put the Chemipure Elite in the second chamber. You can keep the carbon, but it's not needed as the Chemipure has carbon in it. Check the age of your lights. If you don't know how old they are then replace them.

What we're trying to do here is starve the algae out. But your are going to have to do a lot of manual removal also. Do not scrub/scrape nor pull the algae inside of your tank without siphoning. All you'll do is spread it around. Best time to do this is during your water changes.