Nick G

For the last few weeks the water in my 90gal has turned green, to the point where I can't see from one end to another. All readings are fine, all the fish are healthy, and the tank has excellent filtration. I'm a bit stumped as to what the problem is! On thursday I did a 50% water change, totally cleaned the filters and vacumned the sand well. The water cleared nicely, but by yesterday it was green again. Any ideas?

Lucy

Ya know Nick, lots of people try to make green water. lol

Have you tried reducing the amount of light or even a black out?
There's a thread from way back about putting a fresh cut willow branch in the tank.
I've never tried it myself, but it worked for them.

Have you given any thought to phosphates? I forget the correlation between the two, so do some research on that.

Edit: Here's the thread about willow branches: Green Water
It also touches on the phosphates.

Nick G

Thanks Lucy. No I've not tried cutting the lights, I'll do that today. Something I did wonder though.........The tank was set up at the start of summer, so for most of the time the sun has been high in the sky, and the tank was never exposed to DIRECT sunlight. Now though it's nearing midwinter here, and the sun is nearing it's lowest point in the sky, meaning the tank does now get direct sunlight hitting it for some of the day...........

Butterfly

This link explains green water much better than I can http://www.plantgeek.net/article_viewer.php?id=9 seems that bright indirect light might have something to do with it.
As Lucy said SOME PEOPLE can't grow green water even when they try
New fry would love that tank.They would be gobbling up all that unicellular algae and other critters(infusoria) growing in it.
Carol

Nick G

Thats an idea. Would it be worth putting some of the water into my fry tanks when I do water changes?

Lucy

Butterfly

It's good for new fry because the organisms growing in it are so small. Try it on your fry it won't hurt them. You will see them darting around eating if they like it
carol

Nick G

They do like it. I poured a few jugfuls into the newborn tank and they went nuts! Thanks for that guys, another source of food for them, and it's free!

Nate McFin

Get a UV light and never look back. I went with the "Green Killing Machine" from Petco for $60 or so and it was worth every penny.

David593

I had the same problem. I tried cutting lighting times, daily water changes and leess feeding, but it wouldn't work. I don't know what was wrong. Eventually I bought API Algaefix. I put in one dose and my tank was clear within a day. I havn't had to add any more doses and my water has been clear ever since. My other plants are doing fine too.