Can anyone identify the manufacturer of this lid? It's pretty well rusted through and I'd like to replace it. It's steel, two piece, 20 1/2" diameter, with no markings on it. The place I bought the tank, lid and pump (all sold separately) is no longer in business so I can't ask there. Google didn't find a match. Before I go from plumbing supply to plumbing supply I thought I'd trap the collective experience here. Any assistance would be most appreciated.