1. Go get some algaecide -- polyquat if possible -- and put a SINGLE dose in. NO chlorine! NO swimming!

2. Get a cheap OTO / phenol red test kit. Make sure pH is between 7 & 8. If possible lower it to 7.0 - 7.2

3. Do a metals bucket test, to see you have metals in your water.

4. Follow the recipe, once you've done those things.