Re: bracket three posts back.
I like this suggestion. My filter has 9/32 holes 3/4" deep here, not tapped. I will try to drill one out to 5/16 and tap 3/8x16 this morning. Now if I drill thru to water, I will be SHOT by SWMBO.
Never tried tapping plastic. I assume just same tools as metal??
EDIT: ARGH took my ratcheting tap handle to the other place. Need to order another. So, got to wait. This was the backup job while waiting for parts on job 1. So, now i will start job 3. Man would things ever go faster if not waiting for stuff.