Habitat - Indoor :: what causes foam?

[sam 'n ella]

I have noticed in my turtle tank that on about sunday or monday, my tank seems to get a nice patch of foam build up on the water. I do my 10% water changeover weekly, and after that it usually goes away. but then in 5 or 6 days it continually returns. What causes foam in the turtle tank?

[dannypaulny]

I to have a issue with foam. I did not start seeing it until I purchased a filter for my two turtles.

I do know that the foam is the result of proteins in the water. Just like when you cook cook spaghetti or eggs. The water in the pot develops a white foam.

All I can find on the internet is that a good filter will resolve the issue. But like I said, I never had the issue until I got a filter.

Hope someone can help us.