A slight tint is nothing whatsoever to be worried about. There will always be some algae in your water -- spores travel in the air everywhere on the earth. A little algae is good! You are providing an environment conducive for life, which is great, since your fish definately need that. Keep up on the water changes, don't overfeed and do all the things you've been doing to get that tank in the good place it is now, and everything will be fine. My water is slightly green too, that is just a sign of life.