Total Alkalinity Testing - Me vs. Pool Store

[stoles]

Ok. I know the general consensus is not to trust the pool store test results, but I feel like I need to ask for my own sanity...

I have 2 different drop based alkalinity test kits and a ton of different brand strips. One alkalinity test is in the TF kit I have, and the other is in an HTH 6 way test kit. I have tested multiple times over the last month or so and I'm always around 90-110 with both testing options. Even the dip strips give me a number in that approximate range. I was slowly working my way down from initial pool store results when we opened in March that were around the low 200s, and I was happy to be right around where I thought I needed to be. Then I went in the pool store to grab a vacuum head, and decided to take some water with me to get tested. Their TA reading was 22. They told me that was TERRIBLE, and I asked them to check again. They said they got the same thing. I went home later that day and tested again with both the TF kit and the HTH test. I got 80 with one and 90 with the other.

I'm assuming that I need to just ignore the store, but it's SO completely different. Why would their test be off so much if it is the one that is wrong?

For reference, everything else was fairly close that day. The other differences were in CYA (me-30, them 17) and CC (me-1, them 3.6).

 

[PoolStored]

I'm assuming that I need to just ignore the store

^^^Precisely this. That is why we recommend a proper test kit. Making recommendations on pool store testing can do more harm than good.

Signed,
PoolStored.

 

[mknauss]

What is your CYA? Pool store gives adjusted TA. Which isn’t really TA.

 

[proavia]

For your own sanity:

• Toss the test strips in the nearest garbage can
• Never have the PS test your water for anything, unless a trusted member here suggests it (usually only for metals)
• Believe your TFTestkit
• If you start to doubt your own testing, come here and ask questions

Your numbers couldn't be much better that what is shown in your PoolMath logs.
Go enjoy your pool.

 

[AUSpool]

Mixing test kit results and PS results never goes well. Trying to figure out what went wrong with the PS results is almost impossible without more info but basically they botched it up big time which is the exact reason TFP likes to self test.

Your TF and HTH results both concur and are within the tolerance to be close enough to the same although I would forget using your HTH and just go with the TF kit as it has much better quality reagents. I would call your result 80ppm and move on.

From memory the TF and HTH kits use different indicators where the HTH indicator changes colour towards the end of the ideal end point which really means the HTH result would be close to the TF result but maybe a litttle higher as you found. But again just use the TF kit and be done with it, it will save you some time too.

 

[stoles]

I should add that I bought the HTH test kit because I saw it in store really cheap while I was waiting on the trouble-free test kit. I was super anxious to test the stabilizer and alkalinity while I was waiting. To my pleasant surprise, I always get very very similar results with both of those test kits.

Seeing the pool store alkalinity of 22 just made me think I might be losing my mind, so I decided to test with HTH to see where it landed. There was a day that my TF test kit got left outside for a while on a hot day, and my first thought was that I somehow ruined some of the things in the kit.

 

[stoles]

What is your CYA? Pool store gives adjusted TA. Which isn’t really TA.

It was in the last part of my initial question, but my results for cya are 30. The store gave me 17 that day.

30 would be in line with what I expected based on what I added to the pool when we opened and the water that has been drained and replaced since then.

Also I know the HTH kit isn't popular but I get 30 for cya with it as well.

I think adjusted alkalinity is something I haven't learned about yet though. Is there a post with more info on that?

 

[stoles]

Also it really irritates me that I'm in there and they're touting getting your name written on a whiteboard and getting a prize if you have perfect test results. I saw one of my neighbors names up there, and I'm just thinking, " wow... I wonder what her actual results are."

 

[PoolStored]

I think adjusted alkalinity is something I haven't learned about yet though. Is there a post with more info on that?

We don't contemplate or worry about adjusted alkalinity. Just use the TA from the test. Pool math makes any adjustments when calculating CSI.

 

[stoles]

^^^Precisely this. That is why we recommend a proper test kit. Making recommendations on pool store testing can do more harm than good.

Signed,
PoolStored.

It's crazy what I would have added to my pool had I just blindly trusted their results. My alkalinity probably would have been back up in the 200s again. And they wanted me to add oxyshine because of the combined chlorine or something. There was more that I just don't remember. Then they told me that once I added all of the other things, my pH would be off so I would need to adjust that as well.
They didn't sell me anything though. I just told them I had everything I needed at home.

 

[AUSpool]

It was in the last part of my initial question, but my results for cya are 30. The store gave me 17 that day.

30 would be in line with what I expected based on what I added to the pool when we opened and the water that has been drained and replaced since then.

Also I know the HTH kit isn't popular but I get 30 for cya with it as well.

I think adjusted alkalinity is something I haven't learned about yet though. Is there a post with more info on that?

So they stuffed up your CYA too, what a surprise.

Don’t worry about adjusted alkalinity, it’s in the realm of ‘modern man’s chemistry magic’. About 1/3 of the CYA value will show up on the TA test as part of total alkalinity. Here at TFP we only care about total alkalinity. Pool stores like adjusted total alkalinity which is no longer total alkalinity once adjusted but they can say that your TA, which was fine, is now low and you need to buy this over priced bag of bicarb.

Adjusted TA is very close to carbonate alkalinity which, as said, poolmath dose to get CSI.

 

[Lake Placid]

It's crazy what I would have added to my pool had I just blindly trusted their results. My alkalinity probably would have been back up in the 200s again. And they wanted me to add oxyshine because of the combined chlorine or something. There was more that I just don't remember. Then they told me that once I added all of the other things, my pH would be off so I would need to adjust that as well.
They didn't sell me anything though. I just told them I had everything I needed at home.

BUT BUT BUT now you won’t get your name on the whiteboard and qualify to win a clone of a rubber dog turd imported from China with the additional perk of emptying your wallet with a recipe of magic potions.

Congrats on walking away and as others before me have said relax, have a cold one, and enjoy your well kept pool, it misses you.

 

[nieuport17]

What's the prize?

 

[stoles]

What's the prize?

I think it's a coupon or a small gift card or something.