to drain or not to drain, that is the question

[DrBoom]

We've installed a heat pump water heater so that our boiler serving an indirect superstor hot water tank can be turned off in the non-heating season. Should I drain the superstor or leave it full? When/if I decide to use the superstor again, do I need to do anything to the water in it? That is, if we leave it full do I need to drain and flush the indirect before we use it again?
We are on well water with a sediment, GAC and UV filter.

Thanks for your advice.