Greenish Water - What am i doing wrong?

[freshyfish]

I've a 10G planted tank with platy and tetra. I've some live plants as well. My tank used to crystal clear. 2 Months back i changed filter cartridge(after running for 8 months.). When i installed new cartridge, I just squeezed off old filter cartridge inside tank and behind new filter cartridge. Then the problem started. 2 days water was muddy, then it started turning green. I tried water change, it did not help. Then i tried the following.

1. Do a big water change
2. Cover up the tank full without light for 3 days.
3. Open the tank on 3rd day and do a water change again.

This helped for 2 days and water turned green again. This I did twice to make sure that i did correctly. Still no solution. After 3 days, water will be clean for 2-3 days then again it starts turning green . Please help me on what am i doing wrong. Is there any other solution for this?

 

[BigJim]

Never change the filter cartridge unless it's falling apart. Doing so removes a large portion of your beneficial bacteria and throws the tank back into a cycle. If you do think you need to change cartridges, seed the new cartridge by sticking it in the tank for a month before swapping them.

Is your tank anywhere near a window? I had green water issues when my tank was near the basement window. I moved it about six feet away from the window and no more green water issues.

 

[freshyfish]

Thanks for the reply. Yea it was almost falling apart and not filtering properly.

No it is not near window. I switch on lights only for 6-7 hours. I don't know why it still green.

 

[aqua_chem]

GW can be really hard to shake once it gets itself rooted. What kind of light do you have in your tank? Have you done an ammonia test lately?

 

[BigJim]

+1 on the questions. Unbalancing your tank by changing the filter cartridge will create an ammonia spike and green water loves ammonia.

 

[freshyfish]

Yea you are correct. Ammonia spiked. It is close to 0.5 today. I did a water change immediately. I cant believe this happened after an year. It was pretty stable though. I don't know how long it is going to be this time. I had a tough time cycling my tank .