Green water in established tank - what worked

[jfwilson54]

This is related to an earlier thread,
http://www.aquariumadvice.com/viewto...087&highlight=
but I'll post it separately so its easier to find.

I had green water, three times this summer, first two resolved with 3-day blackouts, but it came back. The third time I cleared it up using advice received here:

1. I did 50%/30%/30% water changes and filter cleaning on consecutive days, to reduce excess nutrients that may have built up from fish, feeding, etc. I did these water changes without vacuuming, to not stir up more nutrients. Of course, the aquarium looked a lot better from simply diluting the green water.

2. I upped the ferts and CO2 to encourage plant growth, and did not prune. I also cut back feeding a lot.

The green water totally cleared up in about a week with this approach, without a blackout.

Setup: heavily planted and populated 29-gal with DIY CO2.

[rich311k]

Good work. Now we need pictures of your tank.

[7Enigma]

Which makes total sense since GW is caused by excess light/ammonia. Reduce one or the other and the problem should go away (pending you also have adequate ferts/CO2). By reducing the feedings you cut down on the total amount of ammonia being produced, and by doing the large water changes, you removed the DOC's and quite a bit of nitrAte. By doing both this and upping the CO2/ferts, you put your tank back to where everyone's tanks should be, that is where LIGHT is the limiting factor in the tank.

Congrats.