My IG plaster pool has CYA at around 80-90 and CH above 400. I'm thinking it needs to be partially drained and I'm wondering how best to do it. Being October here in Northern California (Dixon), it's staying cool enough that I'm assuming the plaster isn't in as much danger, but it already has had some problems with thin layers popping off in places so I don't want to exacerbate that. I'm also not sure what the groundwater level is here although since we're only 60 feet above sea level and there's a lot of farming around here, I'm guessing it's not terribly far down.
In fact, I'm wondering if I should take the opportunity while it's drained to repair the plaster that's thus exposed or if I should wait for the summer and do it with the underwater hot plaster. I've done that before on a top step that I could work on without submerging my head, but I'm not sure how well I could do the lower steps.
Is there a guide to draining and refilling including how to actually pump it out?