Well water chemistry - new plaster pool build

Cbarber623

Bronze Supporter
Mar 22, 2020
54
Lexington, SC
Pool Size
25000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Hayward Turbo Cell (T-CELL-5)
I haven't updated my new pool in my bio yet, but will soon. We moved into new house yesterday so we are ready to finish the pool. This gunite was shot in this pool December 15th. We are looking to plaster likely later this week and then fill up. I am on a well, so I conducted water test with my TF 100 and got results below:

PH: 6.8
TA: 40
CH: 50
FC: 0

I also sent the water off for testing and got these results:
1708479885516.png

Overall pretty pleased with the results for drinking water. Should I be concerned with the Manganese level for the pool fill?
 

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C,

Congrats on the house and pool. Do you know who started the pool? I guess before I plaster I'd like to get a basic understanding of the pool condition. I'd especially want to see the pressure test records and other inspection records that should be available from the building department before you go too far with completion. No idea what the water is like where you are but I'd check the total hardness to see if yo need a softener or not. Test strips are worthless for this so you can use a local lab or Hach 145300 test kit (Amazon ~$30). Do you have a softener? I'm guessing you don't have any color or sulfur in the water. Correct?

Chris
 
C,

Congrats on the house and pool. Do you know who started the pool? I guess before I plaster I'd like to get a basic understanding of the pool condition. I'd especially want to see the pressure test records and other inspection records that should be available from the building department before you go too far with completion. No idea what the water is like where you are but I'd check the total hardness to see if yo need a softener or not. Test strips are worthless for this so you can use a local lab or Hach 145300 test kit (Amazon ~$30). Do you have a softener? I'm guessing you don't have any color or sulfur in the water. Correct?

Chris
My Pool Builder has been responsible since the beginning. He dug it, ran all plumbing, electrical etc. and did the shotcrete. He has a crew that does the plastering. We will be using NPT Quartzscapes French Grey.

I did not check for total hardness. I should have asked the lab that did all the other metals for that as well. I'll reach back out to them tomorrow and see if they can do that test as well. We have not installed any type of softner or filtration system. After the test results we got, I was leaning toward no. We have not color or smell to the water.

Thanks for your comments.
 
My Pool Builder has been responsible since the beginning. He dug it, ran all plumbing, electrical etc. and did the shotcrete. He has a crew that does the plastering. We will be using NPT Quartzscapes French Grey.

I did not check for total hardness. I should have asked the lab that did all the other metals for that as well. I'll reach back out to them tomorrow and see if they can do that test as well. We have not installed any type of softner or filtration system. After the test results we got, I was leaning toward no. We have not color or smell to the water.

Thanks for your comments.
C,
That's great you have The builder working for you. Wasn't sure since it was a new house looked like the pool may have been partially completed. If you do ever end up with a softener the hach test kit is something you will want anyway. It's a very simple test and can be used to monitor performance of your softener. You'll certainly want to do this when you first start everything up to make sure it's working after a while you can pretty much tell just by house slippery the water feels in the shower. I still test every few months just to make sure.

Sounds like you have way better water than I do. We have very hard with tannins and about .5 ppm sulfur. Good luck with your new home and pool! You're a little ahead of me on your build. We just got the dig completed yesterday.

Chris
 
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Have you looked into having water trucked in? It may be cheaper than having to replace your well pump. Ask me how I know that. And, the pool will be filled much quicker. Also, the iron may show up using the well. My neighbor had iron stains from using his hose to fill his pool.
 
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That water will be VERY aggressive towards plaster. If you fill the pool with it, it's going to leach calcium from the plaster and slow down the plaster's ability to cure. It's fine to use a fill water to maintain the water level, but I would not use it unless it is treated to raise the TA and CH.

@onBalance - what would you recommend.
 
That water will be VERY aggressive towards plaster. If you fill the pool with it, it's going to leach calcium from the plaster and slow down the plaster's ability to cure. It's fine to use a fill water to maintain the water level, but I would not use it unless it is treated to raise the TA and CH.

@onBalance - what would you recommend.
Matt, very timely comment. Trucking known quality water in that has no iron is difficult or impossible. Still looking but if these are my choices what would you do:
  • Fill with softened and not RO'd. But will contain small amount of tannins that is visible but barely.
  • Fill with RO'd water but add a re-mineralizing filter. RO will completely remove tannins.
Chris

PS Wells have no detectable iron but .4 ppm h2s. I have an aerated activated carbon filter before the softener with a KDF85/catalytic carbon polisher after the sulfur and mixed bed softener that removes all sulfur.
 
Typical well water analysis:

FC 0
CC 0
Ph 7.9
TH 11 gr/gal
Tannins slight
H2S .4 ppm (stinks to high heaven but weathers off quickly)
Iron none detected
Bacteria 0

Around here I can drill shallow to get no sulfur but a LOT of iron, or deep to get no iron but some H2S. I opted for deeper (150') so I have the latter. Thinking H2S would be easier to treat. Not knowing at the time my wife's nose is like a gas chromatograph and easily detects to the ppb levels!

Chris
 
Hydrogen sulfide is less of an issue because chlorine will oxidize it to sulfates. And if you aerate the water aggressively, it will also partially outgas … though your wife might need to wear a gas mask for a while 😂

Aggressive water, defined as water with a strongly negative LSI or CSI, can damage plaster leaving behind a weak and porous surface. When filling a pool, you typically want to aim for a water chemistry where the sun of the CH and TA is roughly 500ppm. The “Bicarbonate Startup” method was pioneered by @onBalance and the TFP recommended startup guides are found in the Wiki -


@onBalance details all of the materials and methods needed to do a bicarb startup. The only major hurdle is trying to convince the plaster applicator to adhere to the science. They often don’t want to be told what to do and they do what they know how to do and believe is right “based on their decades of experience” even on the face of contradictory evidence. They often will only warranty their work if you follow their directions for startup.

If you feel you have a good relationship with that subcontractor, then @onBalance has plenty of detailed info you can discuss with the plaster applicator if you want to have that discussion and try to get them to follow the methods outlined there. But it’s often an uphill battle and you’ll have to weigh your own desires against the possibility of not getting a warrantied surface.
 
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Hydrogen sulfide is less of an issue because chlorine will oxidize it to sulfates. And if you aerate the water aggressively, it will also partially outgas … though your wife might need to wear a gas mask for a while 😂

Aggressive water, defined as water with a strongly negative LSI or CSI, can damage plaster leaving behind a weak and porous surface. When filling a pool, you typically want to aim for a water chemistry where the sun of the CH and TA is roughly 500ppm. The “Bicarbonate Startup” method was pioneered by @onBalance and the TFP recommended startup guides are found in the Wiki -


@onBalance details all of the materials and methods needed to do a bicarb startup. The only major hurdle is trying to convince the plaster applicator to adhere to the science. They often don’t want to be told what to do and they do what they know how to do and believe is right “based on their decades of experience” even on the face of contradictory evidence. They often will only warranty their work if you follow their directions for startup.

If you feel you have a good relationship with that subcontractor, then @onBalance has plenty of detailed info you can discuss with the plaster applicator if you want to have that discussion and try to get them to follow the methods outlined there. But it’s often an uphill battle and you’ll have to weigh your own desires against the possibility of not getting a warrantied surface.
Sounds like I need to read up on a bicarb startup. Thanks much! Since I'm picking and paying the plaster and tile sub I'll have a lot of influence... another advantage of an OB. Final selection will be in next couple weeks and I think I'll have to add a criteria "knowledgeable of real science" as an important criteria.

Thanks Matt, and @onBalance for the great contribution of the bicarb startup.

Each day the hole in the ground is starting to look more like a pool.

Chris

Deep end and spa with start of drain plumbing. Dewatering pump in background with the blue discharge hose.
1708730440803.jpeg

Shot from North end over Robin's grand baby end
1708730662844.jpeg
Preview of sunset over the infinity edge
1708730757485.jpeg
 
Keep silver away from hydrogen sulfide because the silver will react with the hydrogen sulfide causing the silver to tarnish.

4Ag + 2H2S + O2 --> 2Ag2S + 2H2O.

You can remove the tarnish with the process in the video below.

View attachment 555183

Very cool James! Thank you.
 
If you use 240V and 8ga wire the reaction happens REALLY fast … but you’re likely to electrocute yourself in the process or possibly generate lots of hydrogen and blow yourself up 😵☠️
 
Sounds like I need to read up on a bicarb startup. Thanks much! Since I'm picking and paying the plaster and tile sub I'll have a lot of influence... another advantage of an OB. Final selection will be in next couple weeks and I think I'll have to add a criteria "knowledgeable of real science" as an important criteria.

Thanks Matt, and @onBalance for the great contribution of the bicarb startup.

Each day the hole in the ground is starting to look more like a pool.

Chris

Deep end and spa with start of drain plumbing. Dewatering pump in background with the blue discharge hose.
View attachment 555182

Shot from North end over Robin's grand baby end
View attachment 555184
Preview of sunset over the infinity edge
View attachment 555185

Is that paper-backed stucco lath you’re using around walls? Is that your requirement or is it a sandy-soil Florida thing?
 
The well water at site is too aggressive for filling a plaster pool. A Bicarb startup would be advised to rectify that issue.
Another concern is the presence of manganese that would be likely cause staining and should be filtered out prior to filling.
I had a 3 party lab I contracted directly to test water from both wells (both set at 150') and neither well showed manganese at that time. But I've had a real challenge with this water. If you look back (or remember if you read it at the time) I had way more trouble with sulfur than I thought I would. Experimented with direct peroxide injection, aerobic catalytic carbon followed by cationic, anionic resin. Peroxide injection worked well when I could keep it operating. The piston pump vibrates severely no matter what I did and eventually causes fittings at both ends to loosen. Once I solved that the tubing (in sunlight) starts to cause pinhole leaks. Did work but what a pain! Oh and there's a whole other story about getting shipments of 12%. I won't even put the photos up where Matt could see them. Luckily, I found a large 4.5"X 20" polishing filter that contains granular catalytic carbon and KDF 85 that completely wipes out S to levels my wife can't even smell. She reliably detects in double blind samples down to 50 ppb! It's been working great for over 6 months with first air injection catalytic carbon followed by mixed cationic/anionic bed followed by the polishing filter.

I'm looking forward to reading up on your bicarb solution and thank you much for it. Once again, good chemistry may save my bacon.

Chris
 
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Is that paper-backed stucco lath you’re using around walls? Is that your requirement or is it a sandy-soil Florida thing?
Yes, it's typical of every pool I looked at around here. Gives the gunite a surface to adhere to and I guess some kind of barrier but I will also waterproof the concrete on the inside. Next to that I have 1' walls with double mat #3 rebar. Also will be using 3500 psi (design is 3000) concrete and have notified the gunite supplier to build several one sq ft test boxes 6" thick. Testing isn't cheap about $1500 so far from my previous geotech company. The wall spray will be in 2 steps. First the normal pool spray up to the outside of the gutters. Then the finishing crew will insert 2x3"X8' strips of architectural foam. Then the spray the inside section and complete the finish work. Once it sets I pick out the foam and have a nicely formed rectangular gutter around the entire pool.

One thing I learned about concrete from my construction days is warranties on concrete are very hard to enforce and consequential damages are never recoverable. So by far the best way to mitigate failure risk is to pay extra up front. It's not cheap either. There's ~ $3000 for the stronger gunite on a large pool plus the testing costs.

Chris
 
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Is there a gap between the outside wall of the pool structure and the earth? If so, will you be filling that with gravel? Around these parts, the steeltex isn’t needed simply because the soil is heavy clay and caliche. You build the rebar right up to the earth (offset with chairs and spacers to ensure the rebar is properly encased) and then blast away with the shotcrete.

I admit I like the framing and steeltex better but it’s just not something the forming companies do around here for pools. I suppose if you pay them enough, they make your pool walls out of platinum, but the standard forming process doesn’t use the waterproof backing like steeltex.

That pool shell of your will double as an Ark when the earth floods again … you’ll be like Kevin Costner in Water World … 😂
 
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I had to put (27) 9-volt batteries in series to get the 240 volts, but it worked just like you said.

:goodjob:

Funny story … I once connected in series about a dozen 1.5V D-cell batteries using thick copper plates and charged up a 10F power capacitor with it to demonstrate spot welding to a friend. I’m glad I wore my PPE’s and face shield that day because the discharge flash was impressive …
 

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