sweet i will be checking out H H tomorrow.
sorry for jumping in on your thread

Again the HH stuff is fine. Got a sump I made with it going on 2+ years

silicone
 

i've made a 40 gal,2 sumps,3 banger breeders,and a 30 gal breeder with silicone 1 and no problems.it's when i mistakenly used silicone 2 that i lost most of my aptasia