Closing chemistry recommendation

[JimK]

I don't know. It's possible the PQ is a waste. $20-$25. But if it's not, then AT LEAST $20 in chlorine's going in to clean up a spring bloom.

I don't add chlorine over the winter--tough when there's a foot or more of ice. Occasionally, if necessary, I can sneak a thin plastic hose between the ice and the wall, in a corner, and drain of excess water due to rain and snow melt.

Yeah, I was thinking about trying closing without PQ, but then if the experiment fails, the cost of cleanup, not to mention the extra effort, would likely be much more than the cost of a quart of PQ.