Shelf life of Hypo Clearing Agent in storage tank w/floating lid

I have some working strength HCA in a large polypropylene tank with a floating lid, and a cover on top. I have done this for up to a year. I'm not sure, if I should be keeping it like this. I know there's a lot of sodium sulfite in HCA. It's kept cool and dark. I've never had a problem. Am I doing something crazy?
For years I would rack off the stock and keep it in full bottles.

Is there a quick test to see if the sulfite has turned to sulfate?
Best regards Mike

I too would like to know the answer to this. I use the Kodak HCA from powder stock and keep it in floating lid containers also once mixed up (as as I do with D76 and Dektol etc)

Kodak intends HCA to be stored as a concentrate to be diluted 1:4 before use. Dilute sodium sulfite solutions are rapidly oxidized to sodium sulfate which is not as effective in clearing thiosulfate ions from an emulsions.

Unless you have a very large throughput, ie commercial lab, floating lids are not a particularly go idea for storing anything.

Used HCA should not be saved but discarded after use. The used solution will rapidly grow mold which would be transferred to any film or prints passed through it.

The HCA bag should indicate a shelf life for the concentrate as well as correct usage. If not go to Kodak's web site and read any information on HCA.