New TFT reagents, getting much different results

[convan23]

Can you see the difference in the old and new tips?

No. I cannot. I stared and stared and stared. My eyesight is pretty good for things like this... under the right lighting conditions I can point out the imperfections in my wife's diamond on her engagement ring that the GIA says isn't visible to the naked eye (maybe it's a counterfeit! ) ... and I can't spot any differences whatsoever.

 

[Dirk]

It's a bummer because if I didn't have these existing reagents I wouldn't never known better.

Huh, I'm gonna use what I've learned in this thread in an unconventional way. I have the Taylor 2006 (Not 2006C.) It's the kit with the smaller 3/4oz reagents. (I like the smaller size of it.) I try to manage regular reagent replacement cost-effectively. For the reagents I don't use all that much, I just replace the 3/4oz size with a new 3/4oz size. For those that I use more of, like for FC and pH, I buy the 2oz size and use those to refill the 3/4oz containers (because the 2oz doesn't fit in the kit). This allows me to save money when I can and to minimize throwing out expired reagents. But I didn't think of until now that I usually have two of the same reagents "in stock" at any given time, one in the kit, and the "re-filler" in the cupboard. I should periodically perform my testing with the larger-sized reagents, to verify the test results. Additionally, both sizes use the exact same tip, they're interchangeable, so for some of my reagents I have a back up. Coolio.

Don't mind me, just thinking out loud...

 

[DanF]

I just received a shipment of new reagents a few days ago, and just tested my FC today with the new 870/871.
My FC nearly doubled (from 6.0 to 11.0) after using the new FAS/DPD reagents. Obviously, I tested the same way today as in the past i.e.holding the bottle vertically, etc.

I actually tend to believe the results with the new reagents when I look back at my logs from last year, comparing my SWG settings now and then. Just wondering if old reagents (about a year old) could cause the 5 ppm FC variance.

 

[Dirk]

Those reagents claim to last longer than a year, but how they are stored can affect their effectiveness. Plus, depending on where you buy them, they may be well on their way to expiration, or already completely expired, before you get 'em home. They all have dates on them. Have you checked? You can check the old ones for comparison, but you should always check new ones, because they are not always fresh when sold.

 

[DanF]

Fair point, Dirk, but the 870/871 that I purchased from TFT did not have dates. Nor did the old ones I bought from them.

I took a sharpie today and wrote the ship date on them.

 

[Dirk]

Probably not a freshness issue. tftestkits.net claims their product is always shipped fresh. Sorry for the misinfo, the Taylor reagents I use always have dates. It's the stuff you buy on Amazon or at a pool store that you have to check.

Where do you store your kit? Needs to be dark and cool. Just like I like my... oh, sorry, wrong forum!

 

[convan23]

If you want to se if you are having the same problem I did…change out the tips. If your old tips don’t fit, rotate the tips you have. If the results change…you know there’s tip variance.

Fwiw, my Chlorine readings went up to with the new kit, but in my case I’m pretty sure my reagents were old, mainly for improper storage reasons. But now you have me wondering…

 

[DanF]

Where do you store your kit? Needs to be dark and cool.

I store mine in a kitchen cabinet that's approved by SWMBO. So i have dark covered, and the temp is obviously room temperature. Anywhere else, like the garage for example, would be way too hot in the summer.

 

[superuser]

I've resigned myself to only buying the real deal Taylor products for the reasons covered in this thread. I was seeing inconsistencies too until I consolidated on OE genuine products. For me it was better to select the product that gave me confidence the tests were accurate.

 

[Dirk]

I store mine in a kitchen cabinet that's approved by SWMBO.

I don't know what SWMBO is, but mine are in my laundry room cupboard, so same-same, dark, room temp. That sounds fine. Oh, just looked up SWMBO. Got it.

Is there a toaster or coffee maker under that cabinet? They heat up my kitchen cab's pretty well.

Or just chalk it up to "unknown error." I cover for this potential issue in another way. My target FC is technically 5, with a minimum of 3. But I never let my FC get anywhere close to 3. I "pretend" my minimum FC is 5, and it's a red alert when it gets to 4. I'll go 6 or 7, so if it drops a little, it's still 5 or so. I do this primarily to protect against errant FC hits due to extra swimmers, or "bird strikes" or unexpected heat waves, etc. But this strategy also covers for testing errors, user or otherwise. Better FC is a little high, then too low.

The point of testing FC is to make sure there is always enough chlorine in the pool, bottom line. There are a lot of factors that can affect the FC (or testing for it), so give your pool a little buffer to keep it out of the red (or green, in this case)...

 

[revitup]

Most all Taylor tests have an accuracy variance of about 10%, some are worse. That's the word from Taylor tech support. Though it's not clear if that includes user error or not. Other variables include pool volume accuracy, human error, lighting conditions, condition of test vials, age of reagents, etc, etc. The tests are meant to provide guidance for dosing, and they are adequate for that, provided you replace them regularly and store them properly. Using good testing practices consistently, and observing trends, is more important than absolute precise numbers. TFP trusts Taylor's products, and they have proven to be effective and reliable across 100s of thousands of pools. Sometimes good enough is good enough! You can use them with confidence.

Except for the bad bottle tips that are getting through.

 

[Cena_sea]

I admit I’ve left testing kit outdoors since receiving but maybe 2 months later I bought refills to store and those bottles have always been indoors in a hallway cabinet. Recently one reagent was running low in outdoor kit so I got the refills from inside and I tested chlorine both old and new bottle. Same results. I tested ta twice with both bottles. Also same with indoor or outdoor. So since then I’ve just left the refills stored outside too. When it gets summer hot I will bring them back in.

 

[Dirk]

I admit I’ve left testing kit outdoors since receiving but maybe 2 months later I bought refills to store and those bottles have always been indoors in a hallway cabinet. Recently one reagent was running low in outdoor kit so I got the refills from inside and I tested chlorine both old and new bottle. Same results. I tested ta twice with both bottles. Also same with indoor or outdoor. So since then I’ve just left the refills stored outside too. When it gets summer hot I will bring them back in.

Consistent, reliable test results require you adopt proper, repeatable testing techniques: the way you collect the water, what you collect it in, how and where you store your test kit, where you perform the testing and under what type of lighting, how you measure, how you read results, how you clean and store test gear, etc. If you're inconsistent with those things, you're less likely to get consistent results. Same if you shortcut or fudge manufacturer instructions. Storing reagents in a cool, dark spot is part of good practice. I understand that you did an experiment that suggests otherwise. I tend to follow the manufacturer's instructions and TFP's guidance. When I first started taking care of my pool I "interpolated" things like that. It didn't work out so well...

Anywho, you've got some good theories, yours and others, as to what might be going on, and how to proceed.