It's pretty obvious from the way my filter pressure climbs 1 psi/month that it will be a while until I backwash. And it's also clear that I need to water my lawns before they die completely. Right now the grass is sorta splotchy gold/lime green and brittle enough one doesn't walk across it barefoot. And a trip to the dentist and some other unusual expense have ruled out reverse osmosis for another couple months.
So about a week ago I bought a cheap submersible pump. Hey, if I have to buy water for the lawn, I'm gonna milk it for all it's worth. So the lawn gets water with 140CYA and 950CH and the pool gets 0 CYA and ~300CH. I really ought to test the tap water again, they may source it from somewhere different in the summer. Hmmm...
Anyway, the dilution begins. It's taking a lot longer than I thought it would. Who knew a lawn sprinkler restricted flow as much as it does? I expect this to continue now for months and months. It's not as efficient as draining half or more out in one shot and then refilling it, but none of the water's running down the storm drain, either. And my water usage should remain pretty stable to keep the water company off my back.
I'll keep you all posted if the FC/CYA does anything weird to the lawn or not.