Where are you located?
I have a hammer I would love to sell. As I don't ever want to use it again.
If you knew the size of the material you have around the screen we could help you choose a size of screen to use. Are you using the screen covered pipe called gauze screens or the slotted ones that are usually stainless steel?
You might want to move over a few feet and start over. The gunk on the screen is also building up where the old screen is, so each time you pull it and replace it your putting it back in the same old gunk.