New pool chemistry. How to get water chemistry stable.

[mconnell]

I have a new 18,000gal, IG, plaster pool, spa with spill over, ozone system, SWG, Cartridge filter, Hayward system control, 2 speed pump (6 hours low speed and 4 hours high speed middle of the day, chlorinator set at 50%. Initial fill February 16, 2018. The builder added salt the first week which I have discovered is/was part of the problem I have been fighting. Water is crystal clear.

I have been having my water tested by a local pool service on their electronic system about 3 times/week. Initially, I was adding acid constantly trying to drive down the pH. The pH has finally settled into a less demanding pattern. Now I am working on the fine tuning...I think...until I had my water tested yesterday and it was all out-of-wack!!! They suggested 6# of CYU. I doubted the accuracy of the test and took a water sample to another pool service company and the results were drastically different. They suggested 11.5# of baking soda.

Not trusting either result I took a second sample to the initial pool service where I have been testing for the last month. And they ran it on a different machine and the results matched closely with the second service I took the sample to. All that said, I feel like I have trustworthy data to share and ask for your help. Data below are my current values and the ("recommended range") according to the testing company.

FC: 4.7ppm (1-5ppm)
TC: 4.7ppm (1-5ppm)
CC: 0 (0-0.9ppm)
pH: 6.7 (7.2-7.8)
Hardness: 277 (200-400ppm)
Alk: 5ppm (80-120ppm
CYU: 31ppm (30-50ppm) note my owners manual recommends 80ppm. The FC/CYU chart is 70-80 I think.
copper: 0ppm (0-0.2)
Iron: 0ppm (0-0.3
Salt: 3500ppm (2800-3500ppm)

This morning after reading this site I turned the chlorinator off, turned the pump on high speed and started adding stabilizer/CYU in 2# increments. plan to add every 6 hours for a total of 6#. Wait a few days and retest. And then work on the alk levels.? or should I do both at the same time? My logic is change one thing at a time to keep track of the effects of the chemical added so I can understand better the changes that are occurring.

Also, plan on getting my own test kit.

Any and all advise is greatly appreciated,

Mark

 

[peirek]

Hello Mark and welcome to TFP!

So right away you discovered the large variations in testing when trusting pool stores or others to do the work. One of our key tools and requirements is your own test kits and measurements. TF-100 or K-2006C are the two TFP approved/recommended test kits. The kits can be ordered here: tftestkits.net


Your Alkalinity and pH need to be addressed first. Read here on what to do to adjust them. Pool School - ABCs of Pool Water Chemistry
As for how much of what to add use PoolMath at the top of the page.

Typically we see Pool Builders wait 30 days after fill before adding salt.

Increasing the CYA will give your SWG some relief as it will slow the burn off of FC. Right now your FC is good.

 

[mconnell]

Thank you Paul. I am adding Baking soda as directed broken down into 4 increments. I've ordered a test kit. Ill keep you posted and deliver new test results in a few days as the chemicals are fully mixed into the water.

 

[Richard320]

Welcome!

Get your own tester. Really. It'll pay for itself by 4th of July. My suggestion, and the one I use, is the TF100 from tftestkits.net. I suggest the XL option now, simply because that reagent is seldom available locally if you run out. It's better to have the spare handy. I also use a speedstir. Tell you what: nobody who has one regrets buying it. use the search box up top on speedtsir and you'll find several threads. While you're playing with search, check out the term, "pool-stored." Without your own test kit, you'll end up a victim of it. Also a salt tester, also available at tftestkits.ne. And no, I don;t get a commission. Wish I did.