What plaster looks like 2 years later

LisaDLu

Well-known member
Nov 14, 2014
118
Palm Desert, CA
We had our pool replastered in January of 2015. We have kept up the pool chemicals and have been good about brushing. Never had an algae outbreak. We do have very hard water with the calcium hardness rising fast with no real reason (we have been around about that on the forum with no answers as to why except the hard water) so we did a reverse osmosis last summer but it is hovering about 500 now not even a year later. Even with all the time we devote to the pool our plaster has developed some slight yellow staining after only a few years. I can see it probably won't be much longer before it looks as bad as it did before we replastered. Is this inevitable? Can anyone keep their plaster white (or whiteish) and for how long realistically? It is very discouraging. My friend in another state had hers replastered about a year before mine, I visited last weekend and it has some black flecks but still looks overall quite white. She doesn't have hard water issues. So, how long realistically before plaster develops stains even with good care?
 

jblizzle

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May 19, 2010
43,260
Tucson, AZ
You should never get staining. The CH goes up due to evaporation and adding water back into the pool. What is your water source? Does it come from a well? Could the stains be the beginning of metal staining?
 

LisaDLu

Well-known member
Nov 14, 2014
118
Palm Desert, CA
Thanks for the replys. I guess maybe "staining" isn't the right word. Our plaster never looked pristine white from the beginning (it was creamy with creamy swirls) so maybe my expectations are too high. There have never been any metals detected in the water when we have tested for it. We are on city water. There is just a slight yellowing. Probably only 1/2 on a scale of 1 to 5. Nobody would notice unless the water was still and you were looking. I am just curious if anyone with plaster really has the same white after several years as when it was first done.
 

duraleigh

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Apr 1, 2007
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Sebring, Florida
we have been around about that on the forum with no answers as to why except the hard water
That is the answer. You have hard water and must make compensation for it by testing, managing and occasional refills. There is no mystery.

What is the CH of your fill water?
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
15,864
Tucson, AZ
In a plaster pool, water balance is not all about CH but it is an important factor. A plaster pool must have a balanced chemistry where pH, TA and CH are ALL important numbers. These numbers, along with temperature, salt, and borates, get combined together to calculate the calcite saturation index (CSI). If the CSI is kept in balance (-0.3 to +0.3), then you will not have a problem with calcium scaling.

Can you please post a FULL set of pool water test results AND your fill water pH, TA, CH values?

Also, a picture of the "Stains" would help.

As a point of reference - my pool currently has a CH of 1100ppm and yet I have no issues with scaling because I manage my CSI accordingly. Absolute CH values are somewhat meaningless without knowing pH and TA values as well.
 

LisaDLu

Well-known member
Nov 14, 2014
118
Palm Desert, CA
My results from last weekend were:
PH 7.8
TA 70
FC 4
CC 0
CYA 50
CH 500
Salt 3600
Temp 77

I measured the fill water for CH a few times before we did the Reverse Osmosis on it last year and CH was 100. It is really windy today so I will try to snap some photos of the yellowing in the plaster tomorrow and post. Any insight into what I might be doing to contribute to the yellowing is appreciated!
 

JoyfulNoise

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May 23, 2015
15,864
Tucson, AZ
Those numbers are fine. Your pH can vary anywhere from 7.4 to 8.0 ?(if your TA stays below 80ppm) and your CSI will still be in the correct range. Your fill water has really low calcium for a desert climate.

Just a couple of more questions (please excuse them if they seem obvious)-

1. Do you use a water softener? If so, is you pool plumbed to be filled with softened water? Just trying to make sure your source water for the pool is actually the water that reads a CH of 100ppm.

2. What is you frequency of acid additions? Is your pH relatively stable or do you find yourself fighting high pH? When do you add acid (at what pH) and how low in pH are you targeting when you do add acid? Also, are you using liquid muriatic acid as opposed to dry bisulfate acid? (The correct answer is, I always use muriatic acid and would never touch the dry granular acid...)

There are two other tests you can quickly do to test the yellowing plaster. First, fill a sock with crushed up vitamin C tablets (you might have some in your medicine cabinet or you can buy some at the supermarket) and push the sock down by an area that has a good sized yellow stain. Leave it there for 15mins or so and then pull it up. Did the stain lighten at all?

Next, add some dichlor shock powder to a sock or get a 3" trichlor puck and rest it on the stained area for 5 mins (no longer). Did the stain lighten at all?
 

Patrick_B

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Jun 7, 2011
14,999
Midland TX
That should be very easy water to manage, so whenever you can get the weather to cooperate, it will be nice to see the pics. If your numbers look much like that with regularity, you should have very few if any issues. I'm up there with Matt, now knocking on the door with nearly 1000 CH. Oh how I wish for 100 makeup CH.