New to me pool in Phoenix

Sub_Guy_727

Member
Sep 14, 2024
9
Phoenix
This site and the way we care for pools will be perfect for you. :) I spent some time aboard Columbus (SSN 762) back in the 90s.

Phoenix water has significant calcium. I would suggest a soft water fill line for your pool if your house didn't already have it.
The house came with a water softener that is actually pretty nice, so I'm happy about that! Also, a buddy of mine from college was a JO on the Columbus from ~2019-2022, small world!


I'm not sure if this is the correct place to post this, or if I should make a new thread.

My TF Pro test kit came in today and the results are about what I expected - not good. After moving into out new house over the last few days, we've realized the previous owners' have neglected a lot. I'm convinced they never even touched the pool at all, and just let their pool guy come once a week and take care of it. Here's what I found:
  • Pool volume is 12,200 gallons.
  • The pump is a Pentair Intelliflow VSF. It was programed to run on almost full speed from midnight until 11am. I think that's WAY too long for a small pool like this. Eleven hours at 3,000-3,400 RPM? Crazy
  • FC: 18 ppm
  • CC: 0 ppm
  • pH: 8.2
  • TA: 240 ppm
  • CYA: 200 ppm
  • CH: 1000 ppm
  • CSI: 1.38
At first I thought: "no way" but after thinking about it more I think these numbers make sense. I've noticed some calcium deposits growing inside the skimmer, and the high CYA/TA/CH I think can be attributed to years of neglect and throwing in a bunch of trichlor/cal hypo. I ran each test twice to confirm the results, and even tested my tap water to make sure I was doing everything correctly and I'm confident I am. The CYA test maxes out at 100 ppm, but since it looks like a logarithmic scale I assume its between 180-200... either way it's way too high. I've been swimming a few times and it's not very pleasant to swim in and my eyes burn after opening them for a short period of time.

Here's my plan, please let me know if you all disagree or have any suggestions:
  • Perform a 1/2 volume drain/refill of 6,100 gallons (filling and draining at the same time to maintain pool level) to reduce TA, CYA, and CH to more reasonable bands.
  • Perform a sample after 6,100 gallons to confirm chemistry.
  • Continue draining until TA, CYA, and CH are all at or below their specification.
  • Add baking soda/CYA/calcium as needed to return them all to spec.
  • Once there I intend to adjust pH with MA/Borax (depending on level) to get 7.4-7.6.
  • FC can drift down over time with the sun.
If you guys have any recommendations I'm all ears! If this should be posted as another thread just let me know, thanks!
IMG_4993.jpgIMG_4991.jpg
 
Do a complete drain and refill. You can do the No Drain Exchange as you describe if you like, or wait a week until the weather cools a bit and just drain it and refill. Your CYA and CH are very high. Get that settled once and for all.
Your pump can likely run at 1500 rpm or less. Just be sure it is skimming the surface. Timing is likely due to TOU electric rates.
Start reviewing SaltWater Chlorine Generators. You want one.
Start reviewing how to hook up your autofill to your softened water.
Test your fill water CH and TA.
 
My recommendation is a total drain to get rid of the CH and this will fix your CYA too. My CH is over 900 and I'm waiting for 80 deg days to do it so that I can then put my new SWG in. I'm going to start from scratch since my fill water has CH at 150. Then I'm going to run a soft water line 5 feet from my kitchen to the outside wall where the auto fill line is at. If you insist on doing it now then the partial drain will probably have to be done more than once.
 
Do a complete drain and refill. You can do the No Drain Exchange as you describe if you like, or wait a week until the weather cools a bit and just drain it and refill. Your CYA and CH are very high. Get that settled once and for all.
Your pump can likely run at 1500 rpm or less. Just be sure it is skimming the surface. Timing is likely due to TOU electric rates.
Start reviewing SaltWater Chlorine Generators. You want one.
Start reviewing how to hook up your autofill to your softened water.
Test your fill water CH and TA.
Thanks for the advice.

I know there's 2 concerns with a complete drain: damage to the uncovered plaster from the sun as well as the pool turning into a boat and popping out of the ground. If I did a complete drain then fill, I'd obviously wait until it gets a little cooler, or do it in the evening/night when the sun isn't on the pool. Should I be concerned with my pool turning into a boat though?

Thanks for the pump advice. I've changed the running schedule to be at 1700 RPM (1/2 speed) for 8 hours a day. I'm going to continue to lower it to get the optimal speed/run time after I get chemistry fixed.

I just tested my fill water (garden hose):
  • CH: 0 ppm (I couldn't even get to step 3. After adding 10 drops of R-0010 and 3 drops of R-0011L, the water was blue, it never went to red).
  • TA: 110 ppm
 
How are you planning on chlorinating? I'd highly recommend a SWCG.

Pool volume is 12,200 gallons.
When you drain and refill, note the start and end water meter readings. Subtract estimated household usage and you'll have an accurate pool volume.

Eleven hours at 3,000-3,400 RPM? Crazy
Run your pump as slowly as possible while still achieving desired effects (skimmers working, chlorinator operating, etc.).

tested my tap water
What's your fill water TA and CH?

Add baking soda/CYA/calcium as needed to return them all to spec.
You'll never need calcium (your fill water has lots of it). Your fill water should also have plenty of TA, so you won't need baking soda either. Under normal circumstances, a non-trichlor pool will never need baking soda.

adjust pH with MA/Borax
Under normal circumstances, you'll never need borax. pH will typically rise on it own. You will need MA though.
 
How are you planning on chlorinating? I'd highly recommend a SWCG.
Right now liquid chlorine/household bleach. SWG is in the future, just not soon as I just bought the house and have a lot of other things I need to do first.
When you drain and refill, note the start and end water meter readings. Subtract estimated household usage and you'll have an accurate pool volume.
Great suggestion, thanks!
You'll never need calcium (your fill water has lots of it). Your fill water should also have plenty of TA, so you won't need baking soda either. Under normal circumstances, a non-trichlor pool will never need baking soda.


Under normal circumstances, you'll never need borax. pH will typically rise on it own. You will need MA though.
Also great suggestions, thanks again.
Do you have a non-softened water source (hose bib) available? What's connected to your pool's fill line?
Not 100% sure. I just closed on this house 3 days ago so I'm still learning about everything. I know the back yard hose spigot goes through the water softener, which explains the CH of 0 ppm. The pool does have an automatic fill valve but I'm not sure if that's softened or not. I'm going to test it and get back to you all.
With a pump rented from HD you won't be able to drain and refill in one day. That's why you want to wait until the temps are below 90.
Thank you. Another good suggestion.
 
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I just tested my fill water (garden hose):
  • CH: 0 ppm (I couldn't even get to step 3. After adding 10 drops of R-0010 and 3 drops of R-0011L, the water was blue, it never went to red).
  • TA: 110 ppm
Chances are that your water softener is not on a soft water loop. The soft water loop is installed when the house is built and insures soft water everywhere except the outdoor hose bibs (and sometimes the cold water to the kitchen sink). In your situarion, the rear hose bib is soft water.

Check the water hardness from the front yard house bib where the water shutoff is. You will likely find the non-softened water CH is 175+.

Do a full drain and refill after the temps cool off a bit. Even if you only use the rear (possibly soft water plumbed) bib, the softener will will only provide a limited quantity of water before it needs to be regenerated. So after the softener needs a regen, you will be adding hard water to the pool. Just fill the pool all at once so you have a baseline CH. And then look into plumbing the autofill to the soft water line to keep the CH in check.

When doing both the TA and CH tests, continue to add drops until the last drop doesn't change the color any further - and then subtract that last drop from the total.
 
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Chances are that your water softener is not on a soft water loop. The soft water loop is installed when the house is built and insures soft water everywhere except the outdoor hose bibs (and sometimes the cold water to the kitchen sink). In your situarion, the rear hose bib is soft water.

Check the water hardness from the front yard house bib where the water shutoff is. You will likely find the non-softened water CH is 175+.

Do a full drain and refill after the temps cool off a bit. Even if you only use the rear (possibly soft water plumbed) bib, the softener will will only provide a limited quantity of water before it needs to be regenerated. So after the softener needs a regen, you will be adding hard water to the pool. Just fill the pool all at once so you have a baseline CH. And then look into plumbing the autofill to the soft water line to keep the CH in check.

When doing both the TA and CH tests, continue to add drops until the last drop doesn't change the color any further - and then subtract that last drop from the total.
The house was built in 1988 and the softener was installed less than a year ago. I think it taps into the main water line coming into the house, and everything except the irrigation system and pool fill are softened. I checked the hardness from the front water hose and it was 175 ppm just like you estimated.

I bought a submersible pump today, but will be waiting until the temps cool as recommended by everyone in this thread, thanks!

Another note: I added an entire gallon of MA and ran the pump on high for 45 minutes to mix the chemicals. My pH was still reading above 8.2 (see pic), which seems insane that pH is still that high after a gallon of MA in a pool my size. Because my CYA is so high, should I be maintaining FC much higher until I drain the pool? It was 18 ppm yesterday and pool math told me it was low for that level of CYA, so I added some liquid chlorine and it's now sitting at 26 ppm. I know high levels of FC make pH tests not reliable. Is my pH really that high? Or is this not an accurate test due to how much FC is in the pool?

IMG_4996(2).jpg

The above pic is after adding a gallon of MA.

EDIT:

I also re-ran all the tests I did yesterday, and the results confirmed:
  • CYA off the charts, I estimate 180-200 ppm
  • TA: 240 ppm
  • CH: 1000
 
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Hey all, update: after thinking about everything over the last couple of days, I've decided to move forward with the water exchange method for the following reasons, in order of precedence:
  1. Risk. There is always a greater risk in draining a pool. That risk can be reduced and mitigated, but it's never zero. I know enough about this pool stuff to be dangerous, so I want to mitigate risk as much as possible. Sure, water exchange is less efficient, uses more water, takes longer, and is more expensive, but to me those are acceptable trade-offs to completely avoid the risks of draining a pool. While there are added benefits of the complete pool drain (such as calculating pool volume via water meter, starting fresh, etc...) my end goal is to have my specs within the parameters of TFPC, and water exchange will get me there.
  2. The high temperature is projected to be above 100F every day the next two weeks. And, with average highs over 90F throughout most of October, it will likely be another 1-2 months before I'm able to completely drain the pool. I want to correct these problems now instead of living with it over the next two months.
  3. The forecast for next week is around 110F every day, with the high on Saturday being 113F. It sure would be nice to have my pool back in spec to enjoy the last heat wave of the summer :giggle:
I re-analyzed for CYA last night using the dilution method. I diluted the sample with tap water 2:1 and got 70 ppm, multiply that by 3 and my CYA is ~210... pretty close to my guess of 180-200 ppm.

I calculated my submersible pump flow-rate at 6.2 GPM and my garden hose fill rate at 7.5 GPM. The pool water is 79F and the fill water is 91F. I'm draining from the bottom and filling on the top. I have the fill hose overflowing a bucket on the steps in order to minimize the water churn. I'll just leave the pump running and cycle fill water on/off as needed to maintain level. I'm going to do an 80% exchange, which I've calculated to be ~26 hours. When I'm done I'll run the pool pump for a bit and re-analyze everything. If I need to do another session of water exchange I'll calculate it out and go from there. I'll let you all know how it goes.

I want to thank everyone for their help and advice. This forum is really amazing.
IMG_4997.jpg
 
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That is fine to do the No Drain Exchange method.

To keep from having to do it again, I would exchange 100-110% of the pool volume.
 
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I completed the water exchange and it went great! I took mknauss's advice and did a 100% exchange, which equated to 32 hours. It was pretty efficient, and I figure I exchanged ~85% of the water based on my testing.

Pre exchange sample:
FC: 26 ppm
pH: 8.2 (not reliable due to high FC)
TA: 240 ppm
CYA: 210 ppm
CH: 1000 ppm

Post exchange sample:
FC: 4 ppm
pH: 8.0
TA: 140 ppm
CYA: 30 ppm
CH: 150 ppm

My FC, CH, and CYA are all roughly 15% of their original values. The water softener the previous owners put in is fairly large, and I was able to put in soft water throughout the whole exchange process.

Per pool math I added 1/2 gallon of MA and got the following results:

pH: 7.3
TA: 130

Questions:
  1. CYA was a little lower than 30 ppm. I could still barely see the black dot when the water reached the 30 ppm mark, and the dot disappeared when the tube was almost full. I know we round up here and call it 30, but should I add a tad bit of stabilizer to bring it up to ~45 ppm? Or just call it good?
  2. CH is low, but my CSI is -0.4. Should I add some calcium? I'm thinking not to, as the hard water here in Phoenix will raise CH over time.
  3. TA is high, which will drive up my pH quicker. Should I just maintain pH in spec and not worry about TA? Or should I try to lower this down to ~70 ppm?
One last final question that has me stumped:
When I went to start the pump after the exchange, I could not for the life of me get it to prime. I made sure the pump basket was filled with water, checked the pump cover o-ring, checked for air leaks... nothing. I lowered the pump priming speed to the lowest it could go and it finally primed. After the pump started there was a TON of air coming out of the return jets. How did so much air get into the system? I kept the water line above the bottom of the tile the entire time, except for once. The lowest the water level got was ~1/2 inch below the tile, which I intentionally let happen to regenerate my water softener at 2am when temps were cool, knowing the water would rise back up over the tile before sunrise. The jets and skimmer return never got uncovered, so how did all that air get in there?
 
Probably the time it had to sit exposed an air leak you didn't know you had. Check the pump basket seal and at least lube it with Pool Lube with no Teflon. Check that lid for any hairline cracks. Your leak will be on the suction side and that's how air is getting into the filter. Do you have a leaf canister because that lid can leak too. At CYA of 30 you should keep the FC between 4-6 ppm and the high side is recommended. Because the pool could loose 3-4 ppm per day to the sun you should boost your CYA with granular stabilizer to 50-60 ppm so that you can keep FC up to 9 ppm. Use the sock method which is putting an old sock with the CYA in it in front of a pool return and not touching the side of the pool. Then squeeze it every 1/2 hour or so until the CYA is all dissolved. Then wait until the next day to check your CYA reading. Your TA reading should be in the 60-80 range so that you have a better balance with the other parameters. To combat this you can maintain your PH at 7.2 and let the TA slowly drop. After it does then keeping PH anywhere in the 7s is fine. You'll eventually learn where it likes to sit at without you adjusting it much. I would let the CH rise naturally to 350-550. This can happen slowly with the use of LC and MA but if it doesn't then you could put some hard water in as fill or add CH to the pool.
 
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