Green Water

[goldencomet]

recently in my (coldwater) tank the water has gone an algae green colour and i don't know why?

 

[The-Wolf]

there are 3 main causes of an algea bloom

1 ) excessive light

2 ) wrong light frequency

3 ) high nitrAtes (NO3)

so the questions are
how long do you have your lights on for and is the tank getting any direct sunlight
do you know the lightwave out put of your light tube? if not do you know what brand of tube you are useing?
what is your NO3 level of the tank and of your tap water.
how often and how much do you feed? (excessive food can lead to high NO3)

 

[smmetz]

My standard reply to green water:

Do not place the tank where direct sunlight will shine on it.

2. Do not over-feed your fish. They will be fine with 1-2 feedings per day. The food should be all gone in 2-3 minutes.

3. Do not put too many fish in your tank. If unsure, the rule of thumb for small freshwater fish is 1 inch of fish per gallon of water maximum.

4. Do not leave your tank light on too much. For best results, get a timer for $5, and set the light to come on for 4-5 hours in morning, off for at least a couple hours, and 4-5 hours on in the evening. Algae needs light for a few hours to start photosynthesis, while other plants in your tank start using light right away. This lighting schedule takes advantage of that.

5. Maintain your tank. I recommend taking out 15-20% of the water weekly, and adding new water. Vacuum your gravel while taking water out. Treat the new water so it does not contain chlorine.

6. Try adding live plants to your tank. They will compete with algae for nutrients, reducing the algae in the tank.

7. You can manually clean algae from the walls and surfaces in your tank. The glass walls should only need a wipe every couple weeks in a healthy tank. Some fish eat algae on surfaces, which could eliminate this task altogether. Beware, these fish will not help with green water. They may in fact contribute to that problem due to the waste the fish produce, which feeds algae.

8. If all above steps don’t clear your water within a couple weeks, you may consider buying a UV filter. This will kill all free floating bacteria and algae.