DE is Blue Color

[gfritz1]

Just cleaned out my filter and was surprised to see that the DE was a blue color . I have used some algae treatment this year that was a dark blue in color but would be surprised it would turn the DE this color . This is the first time in about 8 weeks I have changed the earth . Anything to be concerned about or anything to look for ? I had this once befoe but then was also getting some staining on the steps etc. Did a metal clean up and have been good since .

[FormerBromineUser]

What algae treatment did you use? It might have had copper in it which "stains" a blueish color.

[gfritz1]

Bingo---in the swim black algaecide treatment 11.4% copper sulfate pentahydrate. So will this mean also metal staining as I dont see any?

I have been fighting for a few years what appears to be black algae stains at various places on the bottom . I think it is coming from the underside of the liner per everything I have researched. We have had a extremely wet summer in Pa and without a doubt have water under the liner and this is when it always appear. If I treat with shock it will lighten but not completely remove and it will get darker each day .Did not appear to be present at opening in April