Is my local pool store wrong?

ChiknNutz

LifeTime Supporter
Jul 22, 2010
145
Arlington, WA
Hello, pretty new on here, but just got a new liner in our pool and filled with well water. We have a reputable pool supply store pretty close, so use them for some chemicals, though expensive, but moreso for advice and free computer water testing. We had them test the water just after filling to see what we had going, results came back favorable as follows: pH: 6.6 / TA: 100 / CH: 225

Next test after adding about 4 lbs of sodium bicarbonate, 6 days later: pH: 7.0 / TA: 60 / CH: 100

Last test after having added sodium carbonate, bicarbonate and chlorine: TC: 1.7 / FC: 1.0 / pH: 7.0 / TA: 70 / CH: 225 / CYA: 0

I tested several times along with test strips and "older" reagent test kits and don't get the same results. If anything, I see a TA of around 150-180 using test strips and 2 different reagent kits. I tested my incoming well water tonight and got a pH of 7.6 & TA of 190-200. My supply store says I still need to add 10-15 # of sodium bicarbonate, but I am not seeing that...what's up here?
 

lightingguy

LifeTime Supporter
Jun 17, 2010
513
Glendale, CA
I think you're going to get a lot of response about bad numbers via the pool store.

My wife saved every copy of test results she got over a 6 month period last year. I looked over them awhile ago with new BBB insight and knowledge - and they are seriously all over the map. Large deviations in CYA, TA, CH and other parameters we never ever touched. It would be impossible for these tests to be remotely accurate.

Obviously that's just anecdotal and my personal experience, but if you are getting your numbers from a large chain store - by a highschool kid with a summer job...... You see my point.

Just look at your CH numbers. Unless you dumped half your pool and refilled with 18,000 gallons of distilled water between your first visit and your second - it can't be correct.

Get a good test kit. You'll never look back.
 

Miranda

Well-known member
Jan 20, 2008
161
Northeast Florida
Yes, your pool store is wrong. These results are erratic and not at all consistent with what you have been doing to your pool.

Evidence: TA dropped from 100 to 60 after adding sodium bicarbonate, not possible
Evidence: CH dropped from 225 to 100 after adding sodium bicarbonate, then went back up to 225, not possible
Evidence: pH very low, but fill water high TA and moderate pH, unlikely if you are chlorinating with liquid, but CYA zero is unlikely if you have been chlorinating with pucks or powder.

Verdict: inaccurate testing = meaningless results.
Sentence: Buy a good test kit.
 

woodyp

Mod Squad
TFP Expert
LifeTime Supporter
Apr 17, 2010
10,576
East Texas
..............tired of that "free"............"computerized".......water testing yet? If they were checking the oil in your car with readings like that, wouldn't you be inclined to pull the dipstick and check it yourself? Get a good test kit recommended here.
 

tim_pool_newbie

Bronze Supporter
LifeTime Supporter
Oct 6, 2009
168
Nazareth, PA
I'm curious just how "computerized" those local pool store tests are. At my local Leslie's pool store, the tests are being done manually - with reagent drops. I'm doing the same thing at home with my TF100 kit - and paying much more attention to the drops being added, I might add!! The first Sunday I dropped by with a test sample, there were 2 high school aged kids, both doing tests for the line of folks waiting their turn. The 2 of them were chit-chatting away, while swirling and squeezing in drops so fast I could hardly count. Sometimes a drop or two miscount can mean the difference between a treatment program for your pool or not.

Even with a Wal-Mart kit, I'd trust my own results over theirs any day.
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
Many of the computerized test stations use test strips. You dip the test strip in the water sample and then feed it into a strip reader, which then tells the computer the levels. The fancier ones use small cups/vials that are individually filled with sample water and then fed through a computerized reader.
 

ChiknNutz

LifeTime Supporter
Jul 22, 2010
145
Arlington, WA
Wow, thanks for the feedback and, ultimately, confirmation of my suspicions. The place is a local mom & pop type shop with a good reputation. However, last week (even though I knew better) the owner sold me 40# of granular chlorine (even though I have a 3" puck feeder) stating that I HAD to get my chlorine up and the feeder just wouldn't cut it since it's new water. The previous home owner wrote me detailed instructions, stating that he NEVER used granular and just turned up the feeder to full upon opening the pool.

Here's the deal, we just did a new liner and filled with well water which I know has a relatively high iron content (actual level unknown, but it's apparent due to stains in the pool and house). We first put in GLB Sequa-Sol to combat the minerals and were told NOT to put in any chlorine until the pool cleared up. So we did that and then started up the chlorine. Almost immediately, we got greenish or tannish discoloration, which tells me it's copper or iron. I go to the pool store and give him the low-down and he trys to sell me algaecide instead. I knew in my gut that it was minerals, but he said he couldn't say either way but that we had to get algeacide and chlorine in immediately. I already had algeacide, but he got me on the chlorine since I figure that this guy really should know his stuff as he's been here a long time and sees lots of folks. Well, all of the above just confirms that they really don't know what the #$%^ they are doing IMHO (other than being good at selling chemicals). Honestly, I think they are doing pool owners a serious dis-service by providing us incorrect information!

So know I am worried I've inadvertantly increased by TA far too much. They first wanted me to add 36# of NaHCO3, I ended up adding 4# and then 16# but now I think that was too much.

Again, thanks much!
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
20 lbs of baking soda/alkalinity increaser will have raised the TA level by about 40, which is fine as long as you are going to continue using the tablet feeder.

Chlorine tablets are generally made of trichlor, which adds chlorine, adds CYA, and lowers PH. Granular chlorine might be dichlor or cal-hypo. Dichlor adds chlorine, adds CYA, and lowers PH. Cal-hypo adds chlorine, adds CH, and is PH neutral.

You really need to get accurate reliable test results. As others have already mentioned your pool store test results are not reliable. There is no better investment in your pool than a top quality test kit. I recommend the TF-100 from TFTestKits.net. The Taylor K-2006 is also good. A good test kit will more than pay for it's self is savings on chemicals you don't need and avoided problems.

How does the water look? Is it at all cloudy/murky or is it clear?
 

ChiknNutz

LifeTime Supporter
Jul 22, 2010
145
Arlington, WA
Yes, looking into the test kits now. My pool liner installer said to get the Taylor 2005, but I see most here recommend the 2006 or TF-100...is that strictly due to the FAS-DPD test that they come with? In practice, what does that do for you? Water is actually looking spectacular now. It was a touch cloudy in the deep end, but has been clearing up daily.
 

Melt In The Sun

TFP Expert
LifeTime Supporter
Oct 29, 2009
3,899
Tucson, AZ
You're right about the FAS-DPD test; that is the only difference between the K-2005 and K-2006. It enables you to get accurate measurements of your chlorine levels, unlike the OTO or DPD tests which require color matching. It is the only test that can measure above 10 ppm as well.
 

Steve456

LifeTime Supporter
Jun 3, 2008
132
Texas
Yes

The FAS-DPD test is a titration test (count the drops). If used as directed it is accurate to .5 ppm. Most people have trouble with the OTO Cl color matching test.

Common practice is to use a OTO color match system frequently and test with the FAS-DPD weekly. If you do a FAS-DPD test and a OTO test you will begin to distinguish the shades of yellow from the OTO test more accurately.

If you suspect that you have algae you will need to conduct an overnight test. This test requires the FAS-DPD accuracy level. Once you have a good test kit you will feel that you are in control of your pool and that you know the chemicals that you need to add to the water.
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,083
San Rafael, CA USA
If need be, you can use a 25 ml sample size with the FAS-DPD test and measure with an accuracy of 0.2 ppm (up to 2 ppm; above that the accuracy is withing 10% of the reading). You normally don't need such accuracy, but the point is that the test is accurate enough to measure very low Combined Chlorine (CC) levels or low overnight chlorine losses. You definitely get your money's worth with the FAS-DPD test, but for quick daily checks the OTO test is fine once you get used to it and "know" your pool's normal chlorine consumption rate.
 

ChiknNutz

LifeTime Supporter
Jul 22, 2010
145
Arlington, WA
In light of all this, I think I may very well need to lower my TA since I *think* it is close to 200 (yes, I have a TF-100 on the way as of this writing). I've read the posts about adding MA or dry acid to lower pH, then aerate as necessary. My question is, what is preferred, if any...dry acid or muriatic acid? Is Dry Acid the same as Sodium Bisulfate? Of course, I will wait until the TF100 comes prior to doing anything further, but all indications show high TA (using test strips and a cheap 4-way reagent kit). Honestly pi$$e$ me off that the local pool store is so far off to make me even go thru this. I'm planning on confronting them on it once the TF100 arrives cuz I think they are really doing us a huge disservice by being so blatantly wrong.