[undy]

I don't think it has anything to do with your sealant or regulator...

The Holley Black pump has no internal regulator like their Red pump does. With a single line system, even with a regulator, you'll see pressure creep. I did and had the same problems when I had a setup like yours. I installed a return line to my tank and used a quality bypass regulator and all my high pressure fuel problems went away.