Draining liquid-loaded torpedo protection in dry dock

What happened to liquid in torpedo-defense systems during dry docking?

It was drained to lighten the ship and reduce stress on the hull while the dock blocks supported it.

The liquid was drained to reduce the ship's supported weight. Once the hull no longer displaces water, the dock blocks must carry it directly, so unnecessary liquid load adds stress and raises the risk of deformation. Draining was therefore a structural and handling precaution rather than a chemical-treatment problem.