Scale Problem?

[Sprocket]

It's been quite a while since I've had any issues with my pool. Due to many issues, I've been negligent so far this year though.

Attached is a picture of the deep end of my pool at night. Lot's of flakes floating on the surface. My understanding is it's scale. Otherwise, the pool is relatively clear. Here are numbers from this morning. I've already added Muriatic Acid to bring the PH down. What next?

TA 60
CH 600
PH 8.2

That's all I tested this morning.

 

[Texas Splash]

After plugging your numbers into the Poolmath Calculator, it's very possible that the particles you are seeing are from excess scale that has been slowly trying to dissolve away from your pool's surface and simply needs to be filtered-out. Even with and elevated CH level, keeping the TA around 60 and pH in the mid 7s helps to keep your CSI slightly negative which should help to dissolve any scale that managed to attach to the pool previously. Now it's a matter of getting filtered or removed via water replacement.

 

[pooldv]

Your high CH combined with high PH is a perfect recipe for scale. As Pat suggested keep your CSI negative, -0.1 to -0.3, to prevent scaling and keeping your TA low at 60 should help slow PH rise. If the surface of your plaster is rough then you can keep your CSI more aggressive, -0.5 to -0.6, and brush often to dissolve the scale. This is a slow process that will take weeks, even months, depending on how long it has been accumulating.

More here, Pool School - Calcium Scaling
And here, Langelier and Calcite Saturation Indices (LSI and CSI)

 

[Sprocket]

Thanks guys. The flakes have only been present 3-4 days. I'll try brushing more frequently and keep the PH down. I also need to take a look at the CSI calculation (I haven't looked). Also I'll keep the cartridge clean.

I may also get some of the stuff that coagulates particles. It has been very dry here and we haven't received much rain, which is probably part of the issue.

 

[Sprocket]

PH down to 7.2 this morning. Added a floculant and it really cleared up the water, although there are still a bunch of flakes on the surface. I brushed the residue to the bottom drain and then rinsed the filter. It's pretty hot these days without much chance of rain. I'm going to let it evaporate down a bit more and add some city water if we don't get some rain soon.

 

[w1sp3rs]

Hi. Been having a scale problem myself for months and I think it's getting worse. Can't get the levels to stay down.

Readings from this morning are FC=7.4, pH=7.4, TA=100, CH is around 750 and last time I checked the CYA it was about 200. CYA is difficult to determine. The calculator says I need to drain 40%, but I haven't got around to that since I need a sump pump. The CSI shows a -0.4. Is that good?

This is the first week that the pH has stayed below 7.7. I added a gallon of acid last week when it was 7.8. What do I need to concentrate on lowering first; the CYA, CH, or what???

Thanks,

 

[pooldv]

Yes, CSI -0.4 is good for preventing scale. You can go up to -0.6 and brush a lot to try to dissolve the scale.

You need to drain to reduce CYA to 60-80 ish.

 

[Richard320]

Hi. Been having a scale problem myself for months and I think it's getting worse. Can't get the levels to stay down.

Readings from this morning are FC=7.4, pH=7.4, TA=100, CH is around 750 and last time I checked the CYA it was about 200. CYA is difficult to determine. The calculator says I need to drain 40%, but I haven't got around to that since I need a sump pump. The CSI shows a -0.4. Is that good?

This is the first week that the pH has stayed below 7.7. I added a gallon of acid last week when it was 7.8. What do I need to concentrate on lowering first; the CYA, CH, or what???

Thanks,

Target the CYA when draining. As a side benefit, the CH will also go down some.

The CYA is a straight calculation, since tap water has none in it. If you want to reduce it 50%, you replace 50% of the water. Before you start, though, get a better reading on that CYA. Mix up a half-strength sample of pool water by mixing a cup of pool water with a cup of tap water. Then use that to run the CYA test. Then double the result. You may find you actually would rather replace 2/3 or 3/4 of the pool water in one go. Yes, CYA can go well over 200 if it's been fed a steady diet of trichlor pucks. Mine was.

CH is a little tougher. You need to test the fill water you'll be using. Say it's 100, just for ease of math. You replace half the water to reduce CYA by 50%. The estimated CH will be (.5 * 750) + (.5 * 100) = 425. Still higher than ideal, but pretty respectable for our area.