A couple of additions to the thoughts already presented -
Once the glaze has hardpanned on the bottom of the bucket, pour most of the liquid into another bucket and use your large pear-shaped trimming loop tool to excavate the layer of sediment. Then when you have it all dug up in chunks, start mixing the liquid from the other bucket back in.
Epsom salt is useful to prevent the glaze from rapidly settling again. I have small jar of a saturated solution of epsom salts that I keep on the shelf just for this purpose. Fill a small jar with a tight lid about 1/2-3/4 full of hot water. Put a few tablespoons of epsom salt in the jar of water and tighten the lid. Now shake it vigorously until the epsom salt crystals have all dissolved. Just let the water settle for a few seconds and look for the remaining epsom salt crystals in the bottom corner of the jar. If the epsom salt is completely dissolved, the solution is not yet fully saturated. Put another 1/2 tablespoon of epsom salt in the water and shake again. Repeat until there are a few remaining crystals sitting in the bottom corner than just won't dissolve any more. Now the water has as much epsom salt in it as is chemically possible. Use this by adding a teaspoon of it at a time to your bucket of glaze. The glaze should instantly thicken slightly as you stir. This is called flocculation, and your flocculated glaze should not settle out and hardpan like before. Note that some glazes will naturally deflocculate after a period of time, and you will need to flocculate it again with another shot of epsom salt.