I'm trying to use kpl's Histomark Black kit (peroxidase) for immunostaining, but I'm getting high background staining (nuclear), even in my controls. After permiabilizing, I'm incubating O/N at 37=B0C in 0.3% H2O2, and blocking for 1 hr at 37=B0C with 3% BSA, prior to primary Ab addition. Between steps, I'm washing 4X. Any suggestions would be greatly appreciated.