25 Gallon tank cloudy water and nothing fixes problem

I have a 25 gallon hexagon fish tank with 6 – 1.5-2” Buenos Aires tetras. I’m having a problem with water clarity. The water has a light fog or haze. These fish were in the tank for a least two months prior to the problem starting. I’ve been trying to clear this haze for 2 months with no luck. I’ve done 50-80% water changes weekly and the hazes seems to return.
I have removed the fish and did a cleaning of the fake plants, fake log and gravel with a light bleach wash. I have recently added a 13w uv in tank light and am finding that the haze returns. I put the light in a week ago and at first was running 12 hours on 12 hours off. Two days ago I started to leave on 24/7. I have a Hagen Aqua Clear 50 filter and have a Purigen 165 insert instead of the carbon pouch. The cloudy water occurred when I used the carbon and was told to try the Purigen which didn't help. I have an air pump.
The guy at the pet store who seems knowledgeable test the water and said everything seems fine within range. He has no idea what it could be. I have tried Algae fix and water clarifier drops with no help. I’ve clean the filter pad with tank water and this is the only item which has not been replaced since this problem. Any assistance is greatly appreciated.

Thanks
Brian

BTW I feed the fish Omega One Super Color Flakes

 

How long has it been since the nitrogen cycle was established?
I suggest getting a test kit instead of trusting a pet store who uses unreliable test strips. Liquid tests are far more accurate, such as API Master Test kit. Knowing the water parameters of your tank helps with many aspects of fish keeping.
Could possibly be a bacterial bloom of heterotrophic bacteria that many new tanks get.
How often to do you gravel vac? Heterotrophic bacteria thrive in tanks that have excess waste since they cannot synthesize their own food like the beneficial bacteria that runs the nitrogen cycle.

 

The tank has been established for 10 months. I didn't vac the gravel until it was established 4 months as I was doing monthly 20-25% water changes and didnt know I should be doing the gravel. . I have since made this a monthly task with water changes. I normally don't do 50-80% water changes at a time but have been trying to shake the cloudy water. I will get a test kit as you recommended. All gravel was removed and cleaned about a month ago. The cloud returned even after the cleaning of the gravel, fake plants and fake log. Maybe by changing the water 50% or so I'm not allowing natural processes to take place. I have had this tank with other fish and plants for 2 years and never had something like this. I'm baffled. Any suggestions on how to remove the cloud, thanks?

Brian

 

I'd try doing weekly water changes 25 to 30%. Can you post a pic? Could be something else other than bacterial bloom.

 

I'm going to leave well enough alone for 2 weeks and see if the tank corrects itself. I will post pics at that time. Let's see what happens.

 

Filter floss? Are you using it? The purigen pad should help Polish the water but may not. It does seem like a bacterial bloom but they usually don't last long. As long as your fish aren't stressed maybe stop changing the water as long as parameters are good. Try feeding half as much or half as often for a week.

 

I feed flakes every morning. Is this too much or should I do every other day. I feed something like 2 pinches. Thanks

 

I had a similar problem when I started out. Cloudy water that would not go away. It turned out that I was feeding too much at once. My wife was feeding the fish a ton at once and they couldnt keep up. When I started feeding them a little at a time (only what they could eat) my cloudy water went away. I feed them twice per day and like I said only what they can eat in a minute or so. Good luck with your problem.

 

You can feed them every other day. No more food than they can eat in 2 minutes. Use a timer. If that clears it up then you know you were over feeding and can resume daily feeding being careful not to over do it.

 

Update:

So when I added the uv light I did a water change hoping the light would help. After a week the lightly clouded water was returning. I did nothing more to the water but decided to change the filter insert as this was the only item that was not changed over the past months since this problem, I was cleaning it monthly with tank water. I put in a new insert and within 5 days the water is crystal clear with no signs of cloudy water. The water looks as clear as a bottle of spring water. Thanks Brian

 

Take the uv light out pls. It kills good and bad bacteria! You tank isn't fully stocked. Are you over feeding? What kind of filter do you have?

 

As long as the light isn't inside the filter it should be fine.

 

Light is outside of the filter as an in tank unit. I have a Hagen 50 filter. For the past 2 years the tank was fine with feeding the same with the fish I had. Have replaced fish as needed. Suddenly the water clouded and now with filter insert changed it seemed to clear problem. I have been chancing problem for past 2 months as noted in first post.

 

I had cloudy water as well at some point and used UV sterilizer for just couple of days. It cleared the water instantly but did not killed good bacteria keeping tank cycled (was checking water with apI test kit). Since then I had no problem with cloudy tank.

Personally I have no idea why some folks are reluctant to use uv sterilizers, they can be a remedy for cloudy tank where other methods just do not work. The good bacteria do not live in water column but in the media of your filters after all, so killing it by uv light is very unlikely.

 

Agreed, the fish are all alive and seem to be doing well 6 weeks after the UV light.