Fish Tank Water Turning Green!

[rikkitiger]

hello,
 
so i have a 20 gallon fish tank with corydoras, black skirt tetras a dwarf gourami and platies, and it is fairly new only had it for about 3 months but do water changes 25-50% every weekend with conditioner and a week ago i noticed no matter how many times i changed a bit of the water, it turned bright green! there is no algea growth at all it just turned green, so i replaed all of it and the filter and it was crystal clear for about 3 or 4 days and then it started turning green. there isnt any brown or residue on the glass and it is the weekend again so i have to do any cleaning this weekend, i changed my filter cartridge again and all my fish seem to be fine but the water is just a bright green and i dont know what it is or what to do about it because i dont have a LFS or LPS i only have walmart, i live in a small town, and so i can't take it in anywhere to be checked for anything. i am wondering if it is a dye in something? i have aquarium gravel, no live plants, and all my decor from petco.
 
what is happening to my water???
 
thanks for any help,
 
rikkitiger

 

[Freedom]

First, STOP changing the filter cartridges.  Each time you do, you remove all the good bacteria you need for a healthy tank, and start a mini cycle. 
 
Do you have a test kit?  What are you getting for readings?

 

[Ninjouzata]

How long are you leaving your lights on? Is the tank near a window? And agreed with what Freedom has said.

 

[KirkyArcher]

Green water is usually the result of high nitrates and phosphates add to that any sort of elevated levels of ammonia into the equation (either from poor filtration, overfeeding, overstocking or disturbing the gravel) and it will be accelerated, A 3-5 day blackout is the usual method to eliminate the green water but you need to lower the presence of the afore mentioned chemicals to stop it returning and adding live plants wouldn't be a bad idea either

 

[rikkitiger]

First of all, i dont have the resources to add live plants. I dont have a test kit and there arent any at my walmart, i looked, i am 13 and dont have enough money to pay for shipping for a test kit, my tank is near a window and i keep the lights on maybe about 13 hours because i cant come home for lunch so i turn them on in the morning and off in the evening

 

[KirkyArcher]

looks like you're gonna be stuck with green water then, Do the black out, (wrap the tank up with blankets to block out all light for about 4 days and don't feed your fish either, no need for lights to be left on if there's no one there to look at your fish, 13 hours is way too long just turn them on when you get home and turn them off when you go to bed and half the amount you are feeding your fish!

 

[WILDER]

It would be best if you could remove the tank from the window.
Turn tanks lights out. Black out the tank.
Get you some information.

http/freshaquarium.about.com/cs/maintenance1/p/greenwater.htm

 

[rikkitiger]

basically there is not a place in my room where the tank is not by the window, but thanks.
 
i will black out the tank, also i am sorry if i was rude before, i just have been so flustered because this whole ordeal has been very aggrivating and i was already stressed. (Algebra End Of Coarse season)
 
i will do the black out immediately, thanks.

 

[Ninjouzata]

What side of the tank does the window shine on? I'm not sure if it'd work but if it's just on the side of it maybe you could put something dark or reflective there to help keep some of the light off of it.
 
I hope the black out works, good luck.

 

[WILDER]

What side of the tank does the window shine on? I'm not sure if it'd work but if it's just on the side of it maybe you could put something dark or reflective there to help keep some of the light off of it.
 
I agree. Was thinking the same thing.
Or pull a blind down if you have one, or even close the curtains  to stop the direct sunlight hitting the tank.