Plaster staining.. what can I do?

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E

eddiejo

0
Jul 13, 2016
28
las vegas, nevada
Hi all,

I have been the owner of this pool for about 2.5 years. This last summer we started noticing staining forming randomly all over the plaster. It's look like penny, nickel, dime and quarter size brownish dirt rings. Then after some time they start to form a whitish rough scale-like mound in the middle. I did some diving to examine and tried rubbing vitamin C tabs and trichlor pucks on it and nothing really changed. I had two pool service companies come out and take a look. One person said calcium build up and he recommended draining the pool and knocking them off with a flat-head screw driver. The other company wasn't sure what they were but recommended a light acid wash do see if that would help. After reading the forums I believed that they were probably calcium nodules and that sanding them and then filling them with under water epoxy seemed like the way to go. But, there were too many so I decided to try the light acid wash to see if that would at least get me back to square one and then I could sand and fill as they returned.

The light acid wash was a month or two ago and I believe they are starting to come back already, which is disappointing and concerning. I thought it would last at least a year before they started coming back. I included some photos of the staining. One is from the pool drain and the other two were taken a few minutes ago with water back in the pool.

http://www.albrigo.com/images/pool01.jpg
http://www.albrigo.com/images/pool02.jpg
http://www.albrigo.com/images/pool03.jpg

Does anyone know what these things are and what I can do to get rid of them? My pool chemistry right now is:

FC 6
PH 7.5
CYA 40
CH 375
TA 130

Thanks,

Eddie Jo
 
The water in Las Vegas is primarily from the LVVWD that uses Colorado River water.

The water typically has a CH of 250 ppm, TA of 130 ppm, and a pH of 8.

I lower my TA to about 70 ppm and then add acid twice a week to manage that during the summer and less in the winter, typically taking my pH from 7.6 to 7.2 each time.
 
My fill water is:

FC = 0
CC = 0
PH = 7.5
CYA = 0
CH = 275
TA = 150

I add acid about twice a week now. Usually 1/2 gallon at a time. Just depends on my PH reading. But I try to keep it around 7.5. So instead I need to get my PH level down to 7.0 and let it come back up to 7.6 and test and repeat until my TA comes down to 70 ppm?

This was my first attempt at a drain and reset. The new fill has been going for about a few months now. I only used CYA powder to start and then liquid chlor and acid.

Thanks!



​
 
Lower your pH to 7.2 when you add acid. That will lower your TA. You will still need to add acid once your reach that TA but should be less.

Your CYA is 0. You should keep at least 30 ppm in the water over the winter and closer to 50 ppm in the summer.
 
Yes, the white raised and rough spots are calcium nodules. While the alkalinity is somewhat high and should be lowered as advised, changing the water balance will not prevent the nodules from forming.

The plaster finish also has "white soft spots" that are smooth to the touch and have formed all over, which are very different from calcium nodules. Those white spots cannot be remedied.
 

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Dive equipment and inexpensive is mutually exclusive...unless uou have lakes or places where people dive, that's going to be tough

Someone was once stocking a lake of mine and was hand throwing fish into lake. The slime from fish allowed his college ring to go flying off..I cut a piece of new garden hose for him and he was able to stay down for 10-15 mins...never found it, but he was able to attempt it
 
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