Booster pump endless draining

Hi there. I’m trying to save as much of my equipment as I can in this Texas freeze. I’ve drained the main pump and am trying to drain the cleaner booster, but it’s just running forever. It’s got some sort of siphon action happening and I can’t figure out how to fix it. Attached is a pic of my system. The yellow pipe says Cleaner, red says Returns. The chlorine stack at the top is a giant block of ice, so I’m suspicious of that, and the valve at the top of the Returns pipe won’t turn. The...

Booster pump endless draining