I like vac sealing bags of water as my weights. Similar to the ziplocs, but more effective and wont bust open. Also good for holding pickles down under the brine.
"God sends meat and the devil sends cooks." - Thomas Deloney
Can you Jerry rig a hook on the bottom of the pot/tub like a suction cupped hook like the ones in bathrooms. Get one of those black office paper clips and blamo! A SV anchor is born.