Noisy drain to sump

[Leon71]

Thanks for everyone's help. Last night I made a "zig-zag" with 4 - 45° elbows and that reduced the boiling by about 75%. Still going to try a few tweaks to this and try to get it even better. Maybe play with the last downtube length and depth in the water.
Cheers, Leon

[mark]

started with Dursos, switched to Herbie due noise in the lines and gurgling in sump. No air, noise.

As for hole size with Dursos, I had 2 drains and flowing ~2000gph, in each cap, hole was only a little bigger than 1/8"