Is this Scaling or something else?

[kchinger]

Wasn't sure if I should put this into here or Under Construction or elsewhere, feel free to move it.

Pool was renovated last June, new plaster, coping, tile. Plaster is KrystalKrete if it matters. I brushed and did everything I was supposed to last year, it was good and smooth and nice when we closed.

On opening, there's hard little nodules on the walls, but only below the winter waterline, and on the floor and steps (again below the winter waterline only) and it's worst in the corners/transitions where it's hard to brush. I can break it off with my fingers for the most part, but obviously I can't do that to the entire pool. My robot has also been picking up a ton of fine white... something this year that wasn't there last year (see picture).

The pH over the winter always climbs a bunch, I close it a bit extra low at like 7.4 but by opening it's 8.2+ and my CSI is sky high due to having to pump CH overboard from rains and stuff and obviously I'm not adding acid since I can't circulate it while it's closed with the cover on.

Does it sound like this is scaling? And if so, how can I fix it now and prevent it happening again over the next winter? Everything was nice and smooth when we closed and now it's much rougher than I'd like.

 

[Texas Splash]

Try pouring a little muriatic acid on that pile of stuff. If it fizzles, and it looks like it might, it's calcium. As you suspect, probably surface build up from the winter slumber. If you continue to maintain a slightly negative CSI of about - 0.3 to -0.6, with consistent brushing you might see more of that stuff get released from the pool's surfaces.

I assume your cell was removed during the winter, so are the cell plates clean & clear of scale?

 

[kchinger]

Try pouring a little muriatic acid on that pile of stuff. If it fizzles, and it looks like it might, it's calcium. As you suspect, probably surface build up from the winter slumber. If you continue to maintain a slightly negative CSI of about - 0.3 to -0.6, with consistent brushing you might see more of that stuff get released from the pool's surfaces.

I assume your cell was removed during the winter, so are the cell plates clean & clear of scale?

Cell was removed, plates are fine. I'll drop some acid on it. I suspected that running slightly negative would work. Unfortunately I tend to run slightly positive, lol. CH is like 575. So I need a decently low pH to get negative. Plus then the generator constantly pushes it up.

 

[kchinger]

Yep, it fizzled like crazy from just a splash. Good to know. I'll work on lowering it a bit and brushing and running the robot.

What can I do over next winter to prevent it? Is there some way to keep CSI good with the pool closed?

 

[Texas Splash]

What can I do over next winter to prevent it? Is there some way to keep CSI good with the pool closed?

Not a whole lot other than typical chemistry prep. You don't want to over-compensate and then have an opposite problem with acidic water. Best to close within the recommended levels as late as possible and open as soon as possible to avoid algae and (hopefully) avoid excessive calcium build-up. @Newdude do you have any other pre-closing recommendation to try and avoid calcium scale?

 

[Newdude]

@Newdude do you have any other pre-closing recommendation to try and avoid calcium scale?

Sadly not much because most of us in the NorthEast are usually adding Calcium from lots of rain and low CH fill water. We don't see many high CH pools so they usually don't scale over the winter.

Kchinger, whats your fill water CH ? It might be easiest to drain some and run on the lower side of the range.

 

[kchinger]

Sadly not much because most of us in the NorthEast are usually adding Calcium from lots of rain and low CH fill water. We don't see many high CH pools so they usually don't scale over the winter.

Kchinger, whats your fill water CH ? It might be easiest to drain some and run on the lower side of the range.

Fill is 75. And yeah, I add lots of calcium during the year to get it up where I need it. Maybe in the fall I'll let the CH fall a decent bit towards the bottom of the range before I close. Dilute if I need to.

 

[Newdude]

Fill is 75

Ok SWEET.

, I add lots of calcium during the year to get it up where I need it.

Why do you need it so high ? 350 will probably be plenty. Stop adding now and it will fall on its own once it gets wet again. Stay open late into the season for more free exchange.

 

[kchinger]

I guess when the temp is low early in the season I end up with a pretty low CSI if I run towards 350. Looks like once it's warm I can run 400 though, so I'll let it drop to there.

If it ever rains, that is.

 

[Newdude]

Looks like once it's warm I can run 400 though, so I'll let it drop to there.

Besides helping the scale if not getting rid of it altogether, you'll save a small fortune. CH ain't cheap.

The high end of 'in range' is for the places that see quick CH rise from fill water and crazy evaporation. They might pick up 300 a year and there's no way they could sit on the low side, as much as they'd like to.

 

[clambert1273]

Besides helping the scale if not getting rid of it altogether, you'll save a small fortune. CH ain't cheap.

The high end of 'in range' is for the places that see quick CH rise from fill water and crazy evaporation. They might pick up 300 a year and there's no way they could sit on the low side, as much as they'd like to.

Hmmm me?

 

[mc2021]

Here's a link to a thread I created a few weeks ago about the same subject, there are a few other ideas too.

Calcium scale crystals

The pool was just opened yesterday afternoon and I ran the first set of tests (tf-100) this morning after letting it circulate overnight. The PH was off the charts high, it took 2 gallons of 31% MA to get it down to 7.7 which means it was around 9.2. My Polaris is picking up a ton of crystal...

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