algea growth on fish tank problem?

Question

my tank is going green rapidly (within 48 hours of cleaning)
I have a filter, so what is happening?!

Answer 1

Is it the water itself (green water) or surfaces (glass, rocks, ornaments) that's turning green?

Your filter only removes solid particles that are large enough to be trapped - if the substances are too small or dissolved in the water, they can pass through the filter unaffected.

The two things you can change to control the growth are lighting (unless you have live plants) and nutrients in your water. For lighting, just turn the lights off completely and make sure there's no direct sunlight on the tank - if there is, you may need to move the tank or cover either that side of the tank or the window.

As far as nutrient control, there are a few things that you can do. Foremost is to make sure you aren't overfeeding your fish. Only give them what they can finish in 2-3 minutes, twice a day - no more. If there's food in the tank after 3 minutes are up, use a net or siphon to remove it.

Make sure you do regular water changes to keep the nitrate levels low - this is the end product of the conversion of your fishes' wastes from ammonia to nitrite to nitrate. Nitrate is a plant (and algae) fertilizer! Use a gravel vacuum to siphon up any debris from the bottom of the tank with each cleaning, and change around 25-35% of your water each week. If you scrape the walls and decor (if that's what's green) and siphon immediately afterward, you'll be removing that much more algae to keep it from reproducing. Also, test your tapwater (if that's what you're using for water for your tank) for nitrates. Some water supplies have both nitrate and phosphate (another plant/algae fertilizer) in them, so water changes can be equivalent to "fertilization". If you can't test these yourself, your pet store should be able to do this for you. You may need to use nitrate/phosphate absorbing media or switch to reverse osmosis water (available pre-botled in many stores and at self serve dispensers at Super WalMarts [the Culligan water uses this process which removes both nitrate and phosphate] for about $0.33 per gallon).

Also, be sure what you're seeing (if this is something that grows on surfaces) isn't cyanobacteria, which has a brighter blue-green appearance - see photo: http://www.aquamax.de/Shop/Artikelbilder/Zusatzbilder/Algen%20im%20Aquarium_Blaualgen%20-%20Cyanobacteria_STUG_cyano1.jpg - as the name implies, this is a bacteria, not an algae, although it does still use photosynthesis to make food.

Here's more on the control of each:
http://www.skepticalaquarist.com/docs/algae/green.shtml - green water
http://www.skepticalaquarist.com/docs/algae/algcont.shtml - algae that attaches to surfaces
http://www.skepticalaquarist.com/docs/algae/cyano.shtml - cyanobacteria

Answer 2

You just sent your tank into re-cycling. Never change all the water. You killed your biological filter(all the beneficial bacteria fish need to survive). So now you have a recently established tank (regardless of how long you've had it) with green water. Everyone had good suggestions about limiting light and so on. They also sell chemicals for green water. Be sure next time to only change 1/3 of the water at a time or your just setting yourself back and making your problems that much more complicated. Good Luck!

Answer 3

I would go in and try to remove as much of the green stuff as possible. Then I would do a black out for 3 to 4 days. By not letting any light in the tank it will clear up the greenness. It could be some bacteria that is thriving off of something in your tank. It could be a mineral in your water it is living off of as well. By replacing your water, you add more of this mineral to the tank and you feed the bacteria. You may want to keep the same water in the tank for a while, let the bacteria starve from depletion of sunlight and minerals and it will correct your issue.

Sometimes introducing plants will help as well. These plants will help absorb some minerals and prevent the bacteria from going crazy.

Just some suggestions.

Answer 4

have you cleaned the filter out aswel??
give the tank a througha clean out all the gravel plants and everythingyou can by algea stuff from all good fish places just go to them and explaine the situation theyll be able to help

Answer 5

keeping the aquarium light on will cause algae to grow faster.
Try cleaning the filter and rocks well along with removing a good part of that water when you clean it. Get an algae eater.

Answer 6

Maybe you have too much sunlight. Is it beside a window ? OR it could actually be cyanobacteria which grows even faster, OR you could have your aquarium lights on for too long. OR you could be overfeeding the fish. It might help to filter your tank water.

Answer 7

Avoid direct sunlight, encourage plant growth to out-compete the algae for nutrients and buy an algae eater such as a pleco (if you have room).

Answer 8

Do you have it exposed to sunlight? There should be no sunlight on your tank any part of the day. Even if it is just 30 minutes, it will contribute to rapid growth.

Answer 9

You can buy some cheap chemicals that get rid of that and wont hurt your fish. It clears up your tank but the algie goes straight to the bottom so you will have to clean it the next day. But it should keep your tank clear. Or you can just buy an algie eater.

Answer 10

Might be time to change the media in the filter system?

That might help??