I have a DE grid filter w/ a multi valve and am getting a small amount of DE back in the pool (but it's hard to tell for sure or if it's just dirt). I am getting abnormal algae issues compared to normal which also makes me suspect something is wrong.

A visual check of the filter appears fine, no torn grids, and I put a new spring in the multi valve.

But is there any way to tell for sure, maybe something I can put in the skimmer to tell if my DE filter is leaking or not?

Thanks.....