Why does my fish tank water always turn green?

Try putting some plants in the bottom or some floating plants like water lettuce. Or use Bacteria Bubble Tabs from http://store.aquascapeinc.com/p/beneficial-bacteri... This is a natural bacteria that competes with the algae for the nutrients in the water. Once you get a good colony of bacteria established you will get very little algae, also will clean up fish waste in the bottom. Tabs are made for backyard ponds so break it in four parts and treat every two days for a week then once a week as maintenance.

It IS related to light.

The green you see is free floating algae in the water. Tiny one celled plants, and these need light to grow.

Is the tank getting too much natural light from a window? When this has happened to me, that's what it was. In winter the sun can through the window at a lower angle, and shone on the tank more. Water went green, and nothing I did changed this. Eventually had to move the tank. Changed NOTHING else about it, and the green water went away.

Also, the more you clean the tank, the worse it gets. You are removing all the fixed algae that would otherwise compete with the free floating stuff, and all the microscopic critters that would naturally eat it. It's often possible to establish a natural balance in a tank after a time, and the water clears up. But cleaning things out all the time stops this from occurring.

Live plants can also help. If you get them growing properly they use up all the excess nutrients (fish waste) in the water, and leave none for the algae. So again you get a balance established without the green water.

But light is 100% part of the issue, and you need to change something about the way the tank is set up, or it will keep coming back in spite of any amount of cleaning or chemicals.

Ian

1. the people at petland, as well as the ones at petsmart/petco/pets at home etc. often give wrong, stupidly wrong advice.

Maybe not always, but every time I've heard anything they've advised.

But in this case they're half right...

2. algae is a plant, it grows with light, and fish waste/fertilizer. Limit those and you have less algae, not no algae, just less. Algae is normal.

3. In addition, algae is not harmful in any way; so never do too much at once thinking your cleaning is better than just leaving the algae alone. Wipe off the stuff on the glass whenever you want, but don't overclean your filter or change too much water

4. Stop overfeeding; yes you are, so stop it.

Take the tank out of the window or cover the side facing the window with tin foil. A good filter system helps. Also I put in aquarium salt with each change. Initially I put in 1 tbsp. salt per gallon water. I change 1/3 water once a month with just a pinch of salt (not table salt). Clean the inside of tank with a sponge on a length of dowel. A syphon cleaning hose helps too to get the old food out of the gravel.

Try leaving the water out in the sun for a day or two before using it to fill your tank. It really helped with my tank, but you have to give it some time. It took me 2 months to finally get clear water that would remain clear until the next water change! I owned guppies, mollies, and Gourami fish, and this seemed to work with raising them.

if its on the glass get snails if its in the water that just happens especially in freshwater and the light limiting will only help with alge

its because the algae in the tank water is floating freely but you should try getting an algae eater if you don't already have one.