Pool store water testing results all over the place

ECan

Member
Jul 7, 2022
8
Florida
Hello!
My husband and I are first time pool owners. I apologize if my post is long, and my questions many.
Our pool is old @ 26 years old, 14,000 gallon, gunite pool. We have a friend who is a long time pool owner, so he gave us a basic pool school. We have relied on the water testing at our local pool supply store.
A few months ago, the water test said our chlorine levels were high. But the the pool was looking a bit cloudy. Our friend came over and said it was algae and to add chlorine, we did, and it cleared up. So, obviously our chlorine levels were not high. Our friend also said you can't trust the pool store testing lol
I bought a Poolmaster 5 way test kit. It doesn't test calcium hardness though. A month ago, the pool store testing showed a CH (is that the right abbr?) of 220 and said to add 10.1 pounds of calcium hardness increaser. Which I now know is an expensive name for calcium chloride. We were headed out of state, so we decided to deal with that when we returned.
Today I used my Poolmaster to check the chlorine and acid demand. The chlorine was orange, so I knew I added too much, but we'd had a heavy rain. I wanted to recheck the calcium hardness. I decided to do a test of my own and took 2 samples of the pool water at the same time, from the same area of the pool, and brought them to 2 different Pinch a Penny stores.
Store 1 Store 2
TC 9.9 8
FC 9.9 8
CC 0.0 0.0
pH 8.0 8
AD 1 drop 2 drops
TA 100 100
So far pretty close, but wait!

CH 225 250
Stabilizer 40 60
TDS 2200 3000

Store 1 said I needed 1.6 cups of acid and 9.5 lbs of calcium hardness increaser. It's interesting that this is the store who had the original CH level at 220, so without adding anything it went up to 225?
Store 2 said I needed 3.2 cups of acid and that was it.

We really want a properly balanced pool, but if we can't trust the experts, what should we do? The Poolmaster test I did, lined up with the Pinch a Penny results as far as pH, AD, and high chlorine (though it only goes up to 5). Both stores had the same results for pH, but one recommended twice the amount of acid. The Poolmaster acid chart said 1 cup.
With an old gunite pool, we are concerned about maintaining the proper CH levels. But without accurate testing, not sure how we can.
Any advice would be greatly appreciated! I'm off to post about my stain issues.

Elizabeth
 

Newdude

Mod Squad
Gold Supporter
TFP Guide
Jun 16, 2019
17,288
NY
We really want a properly balanced pool, but if we can't trust the experts, what should we do?
Trust the science backed experiences of the 321,350 who got here before you.

You need to piecemeal the tests that you don't have to match the full package kits seen here. Test Kits Compared each component is about $30 (plus tax/shipping) or just start over with a full kit.

With those reliable results, we can guide you until you are your own pools pro.

Welcome to TFP.
 

ECan

Member
Jul 7, 2022
8
Florida
Trust the science backed experiences of the 321,350 who got here before you.

You need to piecemeal the tests that you don't have to match the full package kits seen here. Test Kits Compared each component is about $30 (plus tax/shipping) or just start over with a full kit.

With those reliable results, we can guide you until you are your own pools pro.

Welcome to TFP.
Thank you! That article is exactly what I was looking for!
 
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