Would hot tub cover inhibit any of the chemical sanitation processes?

[newtubuser413]

I keep my hot tub covered all the time unless I'm using it, since it is sitting outside and I don't want debris or whatever else to get into it if I'm not using.  Would having it on slow down the oxidization of combined chlorine since it dissipates into gas?  As in, if I shock it and I leave it covered for a few days, would the limited air in the hot tub gets saturated with the gas to slow down the chlorine oxidization process, leading to more biofilm and slower sanitation process?

[waterbear]

Keeping the tub covered while not in use keeps the heat in, minimizes evaporation and keeps debris out of the tub. It will hinder the removal of volatile oxidation byproducts,which is why some hot tubs have persistent high combined chlorine readings.  IF yours are 1 ppm or less after shocking I wouldn't lose any sleep over it. You might want to leave the tub uncovered for a few hours after shocking since this will allow oxidation byproducts to gas off and the high chlorine levels will have time to drop. This can lessen the damage that high chlorine can do to your cover.

Keeping the tub covered will not interfere with biofilm formation or inhibit the chlorine. The first is primarily because of the high bather load to water ratio and the second is primarily from high CYA.  Keeping a tub covered will actually help prevent the destruction of chlorine (and bromine for that matter) from the UV in sunlight.

[newtubuser413]

Always dropping knowledge, thanks @waterbear!