I used 1ml of excel a day in a 10g, and it did not slow down the GSA. I stopped using it a week or two ago and have not seen any increase in the GSA. I did once try spot treating with excel on my anubias. It killed the GSA and left dead spots on the leaves where the GSA was, so I won't do that again.i just moved the anubias from my 10g with 28w 50/50 pc to a 2.5g with 18w 10000k/7200k pc, dose about 2.5ml of flourish excel every 3-4 days. I was thinking of adding an apple snail, but at my LFS some say that snail will eat the plant and others say it will not eat it.