This is a T-siphon https://youtu.be/GVGw4luRndg excuse the end of the world music, but the guy does explain it well. I drain mine from the bottom of the buckets and grow bed, just like you would from
a Bell. The T does take less room in my opinion and was easy to scale for the bad size. For the buckets I bought the smallest diameter that homedepot had for the buckets.

When I replaced my Bell in the main grow bed I used the same 3/4 drain that the bell was attached to then used 3/4 for the main tubes, then narrowed it to 1/2 at the top of the T then back to 3/4 at the drain. I'll try and put some diagrams together. If I can repay all the help that I've received by reading here it's the least I can do.