Hey guys, just a question. I have a 135 gallon with 2x oscars and 3x 4 inch texas cichlids. I have a fx5 fluval canister filter and a aquaclear 70 filter. I do a 40% waterchange every week but still my water turns kind of greenish yellow, and smells kind of fishy after a few days. There is no algae and the tank looks clean. What is the problem?

greenish yellow water means algae. you may not have it on the glass
but in water. its either you don have enough media in your filtering
system, or you have too much light and left over foods. an FX5 alone
can cover a 135 gal tank, thus there should be no issue about it.

did you clean the filter media during water change? if so, how?

Instead of 1 big change a week do 4-5 20% changes at regular intervals

Can you test your water for ammonia, nitrite and nitrate please

How long do you have the lights on for, also do you get direct sunlight on your tank

have you added any wood to the tank recently

over lit and over stocked .....imho

The lights are on a timer and are on 6 hours a day. Is not close to a window either. Ammonia, nitrite and nitrate are perfect. I dont overfeed and there is no food leftover after feeding (oscars wouldnt allow it, little pigs)I will try smaller waterchanges several times a week. I clean my fx5 every 3 weeks. Is that enough?

the big question is HOW do you clean your fx5

You cleaning in tap water? If so your getting about half way between a cycle every time you clean it and starting over...... You need to be cleaning it in old tank water and don't "clean" your bio media, just rinse it off....

Can you post the actual results so we can be sure they are ok

how much do you feed your fish, you should only be feeding what they will eat in 2 minutes

A big water change is better than several small ones. However several small and 1 large water change is better

i clean in old tank water and rinse some off in tapwater if its extremely durty. And the other filter would still hold the beneficial bacteria. I feed my fish for about a minute long. Never longer. I will post the result of watertest later, i didnt write them down and have to do them again.

joker1535 wrote:

that could be your problem right there. the chlorine in the tap water will kill off your bio-filter (the bacteria in your filter.) even if you have another filter running that you don't clean in tap water, you are removing half of the bio filter. which, i think, could cause some problems.

could you post some test results for ammonia, nitrate, nitrite?

delboybully wrote:


Agreed