The vertical pipe (stand pipe) stays vertical, use two 45 elbows to make the horizontally turn. All you have done is add part of your drain pipe inside your GB. If the threaded area on the cap is to small drill it out to the size needed and use AMAZING GOOP. I hate silicone.

You asked "What did you coat the concrete block with"? You need to check out "Fire pit ... AP" by Apollo. All of the blocks were Liquid Nail together, joints were then L.N. again with a Bondo spreader. Cement floor and blocks where than coated with several coat of Henry's best roof coating for ponding water area's. As a safety precaution I added the pond liner just incase my tree ruts cracked my block work.

My supply pump is from Harbor Freight, made by PACIFICHYDROSTAR 1/4 HP, submersible, 2800 GPH, 1.5 IN NPT, with 22 ft of head pressure. The 120 volt / 60 Hz, 6.4 Amps, max pressure 9.5 with a 10 cord. It was bigger then what I wanted but their price and warranty was awesome...so I bought 2, 1 with and 1 without the extended warranty.

ATTENTION ! ! ! I just found out that the pump mention in the paragraph above has the main core made out of metal not, plastic / PVC. I pull the pump to clean my filter netting from debris when I notice what looks like pot metal corroded with acid. Even though the pump was just over its 90 day warranty I took it back. I told them it must have been corroding for sometime...so it became defeated while still under warranty. Got my money returned on both pumps and the extended warranty.