i have a question

Question
We clean our tank every couple of weeks. But only after a few days, the water gets dirty and sort of foggy inside. It even gets harder to see the fish. The color of the water turns from clear blue, to white. We take out some water and we put new water in to clean it out. We also scoop all of their droppings out of the rocks to make sure the water stays clean. We pour in anti-bacterials. We had fish die because of this and that's when we cleaned all the water out and we washed the whole tank. But only after a few days, the water got dirtier than it was before and nothing works. What can we do to keep our water cleaner, longer?
Please answer as soon as possible.
Thank you for your time.

Answer
Sounds like you have on ongoing issue with an ammonia bloom, however the only way to know for sure is to have your water tested for ammonia, which most fish retailers will do for a minimal cost or for free. I would also have them check you nitrate and nitrite levels just so you are aware of where they are at.
This can be caused due to nermerous factors, once you have your water tested get back to me and we can address those causes if need be.