Rough plaster

[marylandpool]

I have a five year old plaster pool that has never had issues before. After opening in late march i noticed the plaster appeared rough and dirty but I couldn't brush the dirt away. Once the kids had the courage to jump in they told me it was very rough like sandpaper. I took the pool water to a pool store and had it tested which showed the Calcium hardness was 400. They told me that was way to high so I drained a few feet and refilled the pool. I got the water balanced again and had it tested at a different pool store , the previous store had bad attitudes and the new one confirmed the water PH was a little high again at 7.9 so I adjusted it . They did sell me 3, 67.6 FL oz container of something called Scale Free by Natural Chemistry and said to pour them all in and start brushing with a metal wire brush daily. Its been 5 days and I haven't noticed a huge difference but the kids said its slightly better. I got in tonight and took these pictures underwater hoping someone can tell me it will just take a few weeks of brushing to fix this mess. I did take a spackle knife and slowly scraped across the plaster and whatever it is comes off after a few passes and the plaster does get smooth but you have to push very hard. Any ideas would be appreciated

Test results as of tonight
pH- 7.6
Temp-70
ALK- 100
CH- 270
CA-30
Chlorine- about 2 with a SWG

 

[zea3]

You had high calcium before you did a partial drain and refill, and the pH was probably high as well. That will cause calcium to fall out of solution and deposit on your plaster surface. You need to lower the pH to 7.0 and keep it there. The calcium will then go back into solution over a couple of weeks. Once the calcium is back in solution you can drain and refill to get rid of the excess calcium or you can learn how to manage higher calcium water so you do not develop scale again.

 

[Texas Splash]

Welcome to TFP! Our PoolMath APP will help you to manage the CSI level (slightly negative). In addition, be sure to test your own water. As you experienced, pool store testing is hit & miss .... usually miss. We recommend either a TF-100 or Taylor K-2006C. Don't bother with the pool store scale gimmicks, they really don't help. The test kit will do you more good. Be sure to update your signature and review the links below.

Pool Care Basics Archives

Your one-stop shop for all things TFP to include: ABCs of Water Chemistry, Recommended Chemicals/Levels, Test Kits, Troubleshooting, and much more!

www.troublefreepool.com

CSI and LSI - Further Reading

www.troublefreepool.com

 

[marylandpool]

Welcome to TFP! Our PoolMath APP will help you to manage the CSI level (slightly negative). In addition, be sure to test your own water. As you experienced, pool store testing is hit & miss .... usually miss. We recommend either a TF-100 or Taylor K-2006C. Don't bother with the pool store scale gimmicks, they really don't help. The test kit will do you more good. Be sure to update your signature and review the links below.

Pool Care Basics Archives

Your one-stop shop for all things TFP to include: ABCs of Water Chemistry, Recommended Chemicals/Levels, Test Kits, Troubleshooting, and much more!

www.troublefreepool.com

CSI and LSI - Further Reading

www.troublefreepool.com

I do my own testing with a Taylor K-2005 but figured I may have another issues so figured the pool store test may help. My own testing is what I posted in my orgianl post from tonight. Thanks for the advice.

 

[Texas Splash]

I do my own testing with a Taylor K-2005

Very good. FYI ..... if you add the FAS-DPD, you basically upgrade your K-2005 to a K-2006. The FAS-DPD is the gold standard for FC and CC testing. Much better than trying to view yellow shades through the OTO viewer. Something you might want to consider. Have a good evening MD.

 

[marylandpool]

You had high calcium before you did a partial drain and refill, and the pH was probably high as well. That will cause calcium to fall out of solution and deposit on your plaster surface. You need to lower the pH to 7.0 and keep it there. The calcium will then go back into solution over a couple of weeks. Once the calcium is back in solution you can drain and refill to get rid of the excess calcium or you can learn how to manage higher calcium water so you do not develop scale again.

When you say the calcium fell out of the solution what do you mean by solution?

 

[zea3]

Science terminology. When something is “in solution” it is microscopic particles dissolved into liquid. Much like sugar dissolved into tea to make sweet tea. The sugar in the tea is in solution. In your case high pH interacted with high calcium and the calcium ( by chemical reaction) came out of solution (pool water) and deposited on the surface of the pool.

 

[marylandpool]

Science terminology. When something is “in solution” it is microscopic particles dissolved into liquid. Much like sugar dissolved into tea to make sweet tea. The sugar in the tea is in solution. In your case high pH interacted with high calcium and the calcium ( by chemical reaction) came out of solution (pool water) and deposited on the surface of the pool.

Great description. So the theory is get the PH down to cause the calcium to go back into the water, remove the water and refill so the problem goes away. Got it and thanks again

 

[marylandpool]

Great description. So the theory is get the PH down to cause the calcium to go back into the water, remove the water and refill so the problem goes away. Got it and thanks again

So is it worth brushing several times a day or is it a waiting game and the chemistry will do all the work?

 

[zea3]

I'm not sure if brushing several times a day would speed up the process or not. Couldn't hurt. You do want to keep an eye on things that churn the surface of the water, such as scuppers, fountains, jets, and waterfalls. Anything that breaks the surface of the water will cause pH to rise over time.

 

[marylandpool]

I'm not sure if brushing several times a day would speed up the process or not. Couldn't hurt. You do want to keep an eye on things that churn the surface of the water, such as scuppers, fountains, jets, and waterfalls. Anything that breaks the surface of the water will cause pH to rise over time.

Good to know and thanks again. If you had to guess how long before I would see some improvement in the roughness of the plaster?

 

[zea3]

Some people report a difference within a week or two, but every pool is different.

 

[marylandpool]

I figured I’d give an update for those that have a similar issue. I’ve been keeping the pH at seven as much as possible but with recent rain it’s going up just a little bit. The roughness has definitely gotten better but it is still pretty prevalent throughout the pool. Hoping a couple more weeks will fix it

 

[PoolGate]

I have a similar issue this year but instead of the entire pool I have around a 1 foot band of roughness. Right around where the winter lowered water level was. My CH is not high only 250 so I'm not sure why i got it. I can pick off the roughness with a fingernail and also tried sanding with a scotch Brite pad. I plan on doing the entire pool that way. I was adding lots of acid in the beginning of the season to lower my ta not sure if that helped at all. My ph is typically upper 7s. I've no clue what happened. Also in my 5th season.