Scrub the plaster during a drain/refill?

[PaulR]

I'm doing a drain/refill due to excessive CYA (seduced by tabs in a floater... oh well) and CH higher than you'd like. As my wimpy sump pump strains to perform this herculean task (I estimate 4 days to drain 3/4 of the water) I'm noticing that the plaster looks kinda dirty. The water has always been clear (at least as long as I've owned this place, about 4 months). A very brief scrub with a hand brush didn't seem to have any particular effect, although I admit it was kind of a token effort.

Should I plan to go at the plaster with something while the water level is down?
Probably not a detergent, but maybe dilute bleach would be okay?
Or is this more likely to be a scale-type problem?
Or does plaster always look like this? I have no idea how old the pool is.

Thanks,
--paulr

 

[gtm]

Before you drain 3/4 of the water in your IG pool, have you checked the water table level? Is "popping out" a worry? Here in FL this could be a disaster waiting to happen. But hopefully the CA ground water level is more lenient ... Gary

 

[PaulR]

Water table is not an issue in drought-stricken CA.
In fact I'm doing this now, rather than wait for spring, so I can get the refill done before the water rationing kicks in.
--paulr

 

[HarryH3]

I did a total drain a couple of years ago. CYA was so high after we bought the place that it took obscene amounts of chlorine to keep the water from turning green and black algae was trying take over. I used a garden sprayer to spray down the entire surface with a 1:4 bleach/water mix. Then I cleaned it all with a pressure washer (be VERY careful if you use one of these, as they have the ability to really mess up the plaster if you get the tip too close to the plaster!!!). For good measure, I then sprayed it all down with the bleach/water mix again, just be sure everything was DEAD.

After all that, I filled it back up and used tabs again for one summer. Once I learned about BBB, I added Borax and started adding bleach. Taking care of the pool last summer was a real treat compared to the previous two! 8)

 

[gtm]

Water table is not an issue in drought-stricken CA.

Sounds good. Not the drought, you know, but that you can drain without worries. I just wanted to make sure that you knew about the popping out danger, but you're clearly on top of things. Based on my experience, getting the CYA down will help a lot. Here in FL, though, I had to drain much more slowly!

 

[Johnny B]

What is "popping out "?

Thanks

 

[PaulR]

If you have an in-ground pool, and the water table (i.e. how far down you dig before reaching water) is higher than the bottom of your pool, then when you drain the pool you are turning it into a boat. It can "float" on the groundwater -- popping out of the ground. Some main drains have a relief valve that will let groundwater in if you drain too far, to keep this from happening.
--paulr

 

[JasonLion]

To get back to the stains on the plaster: In addition to thinking about how much they bother you, and how much work you are willing to do to remove them, you could experiment to find what will take them off. Organic staining will generally come off with very gentle rubbing with a wet trichlor tablet. Calcium scaling will require acid. Some things will come off with some gentle brushing. Metal stains often respond to holding a wet Vitamin C tablet against the stain for 30 seconds.

If they are calcium scaling, you will need to do an acid wash to remove them. Doing this now will save some effort, since the pool needs to be drained to do an acid wash, but it is still a large project. Metals and organic stains are best treated while the pool is full.