I've got two tanks - 29G and 10G, see the details below.
I've struggled with green water for about 2 months in the big one. It started right after I set up the tank as a slight white cloudiness and with the time it turned into peas soup. See the picture here
. There were moments I couldn't see further than couple of inches beyound the glass.
I've spent long hours in the internet gathering information about how to get rid of this nuisance. I saw many different suggestions on this theme, but nothing worked for me. I tried covering the tank in total darkness for days, bleaching and re-establishing it from scratch, changing the substrate... Needless to say, I was very pissed off at everything green & cloudy and was too anxious to get my water crystal clean.
After I was already tired of trying to clean my water and was an inch away of giving up, I decided to change the light of the tank and keep it for longer this way (I have hard time giving up anything and this is a big problem of mine). I removed the 60W power compact light from the canopy and replaced it with a 15W fluorescent one. Nothing seemed to have changed after a week with the new light. However, as a last try, I decided to treat the water with one of these synthetic drops (accuclear) that stick the microscopic particles together and clean the water. I had used these before against the bastard without much success. This time it worked perfectly. It entirely cleaned the water leaving it crystal clear. Then I read somewhere that this magic solution traps the dead algae into the filter, but not the live one. This explained why it worked this time.
Clearing the water in the tank was good news, but I was sure that if I replaced the light back (with the 60W PC) the green bloom was going to come back too. Unfortunately, there was no way to attach a dimmer to my power compact. Thinking about now to dimm my power compact I finally dropped any hi-tech solutions and decided to go the neanderthal way. I simply covered the glass of the power compact with several sheets of white paper and found out that the light output went down to almost the one of the 15W. I kept it like this for a couple of days and started gradually increasing the light intensity by punching more and more holes through the paper each day. After two weeks I removed the paper completely and the tank was still crystal clear. It seems the bio ballance changed and the intense light was not causing green water any more.
After having won against the green clouds, I started paying attention to my plants. Surprisingly, they were growing much faster when the water in the tank was green. I concluded that this was the normal growth rate of the plants and since they slowed down their growth after I cleaned the water from the algae, I decided to do something to increase it. I started fertilizing both my tanks with PMDD. I was more aggressive with the 10G and very gentle with the 29G (since I knew how hard it was to clean an algae bloom
After going "gentle" on the PMDD with the 29G it started to grow spot algae which turned into a kind of slime coat algae at the end. It was easy to clean it. It appeared what I was considering "gentle" was not gentle enough for the tank at all. It was way overfertilized. The funny part was with the aggresivly fertilized 10G. It grew so much of the slime coat green algae everywhere on the plants and the glass that it looked as if seen through green glasses. So, here I go making my next mistake. I went aggressive again and cleaned up everything, trimmed the plants and made a big water change. After a couple of days I was "awarded" with a nice green water for aggressivness in the 10G again.
However, thanks to my previous experience, I was calm and knew what I could possibly do to get rid of my "award". I made a big water change and switched off the lights of the 10G. I was pretty fast and on the third day of "darkness", I added Accuclear just to test whether the water will clear up. For my surprise, all the algae from the water got (trapped) into the filter just for one night. The filter pads were greener than the Brazil's flag. There was no trace of algae in the water too. It was crystal clear. I did the same "paper" procedure with its light and it worked perfectly again. The water stayed clean "everafter". The plant growth slowed down a bit too, but this was a small price to pay. In addition, I'm sure there must be a way to get the plant growth up to the one in green water, but I have to correct my "gentleness" to normal levels.
I hope this story would help you guys to get rid of your green couds too. I suspect that if your water is averagely clean of phosphates and nitrates it should work with your tanks too.
another hobbyst (still)
3mm grave with laterite;
5 tiger barbs, 3 SAEs, 8 Amano shrimps
7 mixed crypts
5 baby saggitarias (the number is quickly going up)
2 bushes of rotala indica
some java moss
2 bushes of pigmy chain sword
Eheim 2160 canister filter
60W power compact light
yeast CO2 injection
standard 15W light
2 Amano shrimps
1 Aquaclear 150 power filter