Activated carbon and algae issue

[jcmjoe]

Have any of you guys ever had an issue with certain brands of carbons possibly leaching phosphates or anything undesirable into your tank. I had a sudden brown algae bloom over my sand bed and the only change I did was swap out some Phosguard for some carbon in my reactor? It was a new bag of the fluval / aquaclear that I put in. Just curious, Im not showing a huge spike in my test but thought I read in the past that some of the cheaper carbons can do that.

Thanks!