A recirculating chiller, using a mechanical refrigeration unit is popular. These can be configured to provide the mandatory electrolyte agitation as well.
For my 5 gallon "research tank", a 1/4 HP chiller can deal with 300W of power dissipation and hold the electrolyte at 32 deg. F..
Be advised; Caswell Plating and I are not prepared to support Type III anodizing. If you get into trouble, you're on your own.
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