He says, pool store says...

[jellyfish]

I just measured my pool with the TF 100 testkit: [Edit to correct name of testkit:Butterfly]
Free Chlorine: 3.5
Total Chlorine: 4.0
pH: 6.6
Total Alk: 50
Cyanuric Acid: off the chart, somewhere around 150

Seeing the total alkalinity and pH are very low, I started by adding a 6 lb bag of Baking Soda.

I couldn't believe my Cya is 150, so I took a sample to the pool store to verify my own readings.
Pool store says:
Free Chlorine: 5.0
Total Chlorine: 5.0
pH: 7.1
Total Alk: 20
Cyanuric Acid: 80

How can the pool store's computer give readings SO FAR off from my readings?!
I'm especially concerned by the TA and CYA.
I got 50 TA, added 6 lbs of Baking Soda, then the pool store read 20?!
I got ~~150 CYA, the pool store got HALF that?!

I don't know which to believe, because they are so totally different.

 

[jellyfish]

Just to be complete, the pool store was using a computerized test kit. The pool guy filled a syringe with my sample pool water, and proceeded to punch the syringe through the paper covers of 6 to 8 square vials with different reagents in them. He then put each square vial in turn into a computer slot which read the results.

 

[uwimage]

Must be Windows :lol: (sorry, had to!) :-D

 

[Guest]

That would be a LaMotte Waterlink Express system. It's decent but has some limitations. If the CYA test did not develop for a full three minutes from the time it was filled it will read low.
If FC is above about 3 ppm the TA will beach out and read low.
pH is usually very accurate and agrees with Taylor and TF100 results, ditto for chlorine if chlorine level are below 10 ppm. If they don't agree I would look to testing error. Ask the pool store person if they have passed the Waterlink certification from Lamotte and to show you the certificate. If they have they are probably testing right.
(BTW, I use this system at work and back it up with a Taylor kit for certain tests under certain conditions.)

 

[duraleigh]

Believe your TF-100.

Test once more for pH, and if you get the same thing, get some Borax into your pool. and bring it up to 7.4-7.6.

pH that low needs to be corrected right away.

No matter what system they have, pool stores are infamous for innacurate testing.

Secondly, why do you not believe your CYA? Have you been chlorinating with pucks and/or shocking with Di-chlor?

Last, I was hoping someone else would respond to your post letting you know about pool store testing.....I have an obvious agenda. Nevertheless, others will be along soon and confirm that pool store testing is very, very often wrong and the TF-100 is seldom incorrect.

 

[SeanB]

Ask the pool store person if they have passed the Waterlink certification from Lamotte and to show you the certificate.

You may keep your in you back pocket, but I'm guessing the average pool store worker, certified or not, probably isn't going to cooperate with this request. I can see them going home to the wife and telling her about this one customer....

A big part of testing is consistency. The CYA test is somewhat subjective, so it's really best to have the same person test it the same way each time - that would be you. Remember you are shooting for a target within a range. If you get in the range, you are good.

 

[Guest]

My certificate is on display at work! Boss wants them on display. (LaMotte made sure it was suitable for framing! It's an 8x10 with a gold seal on it! It's a good marketing tool so people 'trust' our test results and it does insure we know the proper way to test with this system.) My whole point is what Duraleigh was saying. It's an excellent testing system for someone that understands it and it's limitations but for someone who is not properly trained in it the results will be very inconsistent! If your TF 100 results are repeatable 2 or 3 times on the same sample then trust them!

 

[TizMe]

Im sure Jellyfish can do a search for "pool store testing" and see several threads about inaccuracy of the testing vs TF100 testing. I think it was AnnaK who just posted on here about taking a water sample to 3 different stores and getting 3 different results.

 

[SPP]

I have a portable electronic Ph meter, some Taiwan brand.
Studying at the maintenance and the calibration required, I gave up on it since I don't need 0.1 ph resolution.
I am sticking to Pentair 5 bottles test kit for PH because I can add #3 drop by drop, my eyes can't differentiate well between 7.6 to 7.8 pink color, so I use #3 to get it to 7.2 where the color is more of orange....just to make sure I was seeing a real 7.6.

For other test and especially FC & CC, man.... I love the TF-100.... I also follow the "hold the bottle" upright...really upright when doing drops and make sure no static electricity reduce drop size due to the dropper head being "sticky", these two precautions as per Taylor website does make a difference if FC is above 5PPM where 10+ drops required. I get 0.5PPM difference for 7PPM level between me and my pool boy who holds the bottle at an angle.

If that Lamotte uses "color sensor or light sensor" as measurement method, having it not calibrated as per factory spec regulary will sure produce error in the long run. I think some dust or dirt on the light and the sensor will throw off the readings. I guess it will be the same as using expired chemical test kit....

Many people get amazed at computerized testing equipment, but it is only as good as its "correct" calibration and when callibrated periodically as per manufacturer requirement. :handshake:

 

[jellyfish]

The pool store guy took about 3 seconds to get each vial into the computer and get a readout; So, no, the CYA test did not develop for 3 minutes.

 

[AnnaK]

Im sure Jellyfish can do a search for "pool store testing" and see several threads about inaccuracy of the testing vs TF100 testing. I think it was AnnaK who just posted on here about taking a water sample to 3 different stores and getting 3 different results.

Two stores, two different results, neither of which agreed with my TF-100 but the computerized one was really way off, reading a CYA of 20 in water that's had a trickle of trichlor going in all summer. Same experience as jelly's with the 3 second tests.

My CYA reading comes to 40 - 50. They wanted me to add 2.5 pounds of stabilizer which, if I had followed that advice, would have raised CYA to around 70. Not really awful this late in the season, but not good advice. If it were earlier in the season I would be on a terrible merry-go-round: an overstabilized pool, not enough chlorine, algae, and would have been at that store three times a week buying more and more and more stuff to clean up my water.

I was to add nearly 30 pounds of "hardness increaser". Can you imagine dumping 30 pounds of calcium chloride into your vinyl pool? I can't. A 45# bucket costs around $60 or so. How much is a 50# bag of Flash Melt (calcium chloride pellets)? About $30.

It's just such a racket, running inaccurate water tests, then selling unnecessary chemicals which are practically guaranteed to mess up a pool which, in turn, assures that people come back to buy more chemicals - all summer long.

I do not mean to offend any of the pool professionals on this site and I hope you're not reading this post as such. You've all been very helpful and I've relied on you many times. And I don't begrudge a business its profits. Free enterprise is what keeps all of us going. But I do not like the manner in which some pool stores gain those profits.

Ok, off my soap box.

 

[TizMe]

I thought it was you Anna, who had that happen to them !

We need to get SeanB or someone to get a "soap box" emotion icon for this site it looks like :lol:

It seems to be being used a lot lately :!:

 

[Cherie]

I don't know if Leslie's meant to steer me so wrong, from day one. But they did! And if I continue going there, they keep on giving me bad, bad advise. Our liner is already bleached some because of their advice. AND, you can get two totally different sets of instructions from the same store by two different employees!

But just a short example: A few weeks ago, I took water in for them to test just for fun - since we had to go there to buy some pool equipment anyway. The employee told me our phosphates were a little high (at 150). I said "OH MY GOSH! I'll get some Phosfree in this afternoon!" and left, with a hidden smile. Well, just for fun, I went back the next day - yes, it was worth the gas expense - and voila', our phosphates had dropped to just 50 or less. I asked her how they had dropped, because I hadn't put the Phosfree in yet. She had no answer and stumbled around a bit. I'd bought Phosfree early on this summer when we first had our pool put in ...BEFORE WE FOUND THIS SITE (so, cut it out everyone...I know better now!!)

Anyway, this lady DOES know quite a bit about pools...I thought. She didn't know that chloramines were formed when the contaminants attached to the chlorine, thus making that part of the chlorine no longer useful! I was shocked at that. Doesn't matter anyway. I only have them test for the fun of it -- and giggle at their results!! I HAVE MY TF-100 in my holster!!

 

[Guest]

The pool store guy took about 3 seconds to get each vial into the computer and get a readout; So, no, the CYA test did not develop for 3 minutes.

I rest my case! LaMottes instructions clearly state that the CYA and metal tests needs to be read AFTER 3 minutes!
Trust your own testing!
Edit: just checked the online waterlink instructions and they are different then the hardcopy ones I have. The new instruction include the optional borate and nitrate tests but list the mimnum development time for the CYA test as 2 minutes now. The printed instruction I have are older and came out before the borate and nitrate tests were available as an optonal upgrade to the unit.
http://www.lamotte.com/pages/common/pdf ... 4-01P1.pdf

TW, there is a bit more than this one document to the instructions. There are the interferencec to certain tests that need to be taken into cosideration (TA, CH, pH), the range that the meter can read and what happens if the test is out of range (such as calcium levels above 500 ppm) and also the acid and base demand tests that are not available on the LaMotte website so it really does take a bit of training to use this system properly which probably explains why there is so much bad water test results from pool stores. Then again, a Taylor lab in the hands of someone who does not know how to use it will produce just a bogus a result!

 

[Butterfly]

I don't know which to believe, because they are so totally different.

I would always trust my test kit over the pool store. :-D (I also use the TF 100 and love it!)

If you are uncertain about how to read the CYA test, you may want to take a look at this: http://www.taylortechnologies.com/Chemi ... ntentID=44

And, as duraleigh commented, I agree that the pH issue needs immediate attention.

When you have some time, please add your pool & equipment info in your signature. You can go to the User Control Panel (located upper left under TFP logo), select "Profile" then "Edit Signature".