New TFT reagents, getting much different results

[convan23]

Just received a refill set of reagents from TFTestkits. My calcium test results are coming in much hotter then my previous reagents. My old reagents are Taylor-branded bottles, and they are still in date and stored indoors.

Pool was filled fresh on Jan 11 (after a plaster repolish). On Jan 12 I added 48lbs of calcium chloride to bring my 150ch fill water up to around 500. This worked as expected, and fast forward to a few days ago my water was still reading in the 400s.

Today with the new reagents I am getting 625+ ch level. I did the test three times from two different areas in the pool. I’ve narrowed it down to either the r0010 or r0012 reagents as being the culprit, I get the same results with both indicator solutions.

Fwiw, my water district reports municipal water calcium levels in the 58-62ppm range and chloride in the 23-78 range. I would think this means my 150ch reading of my tap water with my old reagents as fairly accurate.

Am I right to think the new reagents has some issue, perhaps in the bottle/dropper? Or is it more likely my old reagents are really that bad and my calcium is really this high?

 

[ajw22]

See the note in...

Calcium Hardness

A drop-based test that measures the hardness in your water. Once measured, it is used … Read more…

www.troublefreepool.com

Hold the dropper bottles vertically and squeeze gently, so that drops come out slowly and seem to hang on the tip of the dropper bottle for a moment before falling.

Or there have been some problems with bottle tips not forming the correct size drops.

Do you use a Speed Stir?

Do you still have your old reagent bottle?

 

[convan23]

I am not holding the bottles vertically. Closer to 45 degrees. But I’m doing the same thing with both the old reagents and new reagents. I will re try in the morning.

Do you use a Speed Stir?

Yes.

Do you still have your old reagent bottle?

Well, I have the Taylor reagent bottles, but they aren’t empty yet and what I was testing against. They’re different size bottles.

 

[proavia]

Reagent bottle needs to be held perfectly vertical.
Let the drop fully form on the tip. Don't squeeze the bottle too hard and force the drops off.
Drop rate should be about one drop per second.

 

[convan23]

Same results this morning practicing better dropper etiquette (form?)

18 drops of r00012 with old re-agents, 24-25 drops with the new TFT re-agents.

Here's a video showing both tests I made:

At this point I don't know whether to think that my CH is really high (625 range) or where I've expected it to be all this time (450 range).

I repeated the same test with my tap water, getting 8 drops (200) on the new re-agents and 6 (150) on the old. Not sure what to make of that. Again, municipal water reports calcium levels to be between 58-62ppm and chloride levels 23-78ppm. Both 150 and 200 are on the high end of that range, but probably within error tolerances of the drop test...

In January I added 48lbs of calcium chloride. Pool Math shows that should raise my CH by 346. Even if my fill water is 200CH as the new re-agents are suggesting, I would expect my maximum CH to be 546, and to be lower then that today due to evaporation. This leads me to trust the old re-agents, and I'm not sure whether I should be looking at getting a new dropper or?

 

[mknauss]

Take the tip off the R0012 old bottle and put on the new bottle. Repeat test with new bottle.

 

[convan23]

Take the tip off the R0012 old bottle and put on the new bottle. Repeat test with new bottle.

IT looks like my Taylor R0012 bottle tip doesn't fit on the TFTestKit bottle (smaller diameter).

I have other old TFT Bottles (not an old R0012 bottle though) how do I know which re-agents use this same drop size?

 

[mknauss]

All the clear reagents use the same drop size. I think the colored ones do to, but those get gummed up some.

 

[flynwill]

On this subject, anyone here know what the weight should be for a drop for these various tests? I have a small digital scale capable of weighing fractional gram masses with reasonable accuracy and it would be interesting to find out if a drop is a "drop".

 

[mknauss]

It is a volume. And it was stated in an older post. I will look.

 

[mknauss]

In a Wiki! Of course it is --
Each droplet is assumed to be 40uL but, in reality, the volume of each droplet is highly dependent on the individual.

Water Testing Errors - Further Reading

www.troublefreepool.com

 

[ajw22]

It is a volume. And it was stated in an older post. I will look.

Pool Test Kits - Further Reading

www.troublefreepool.com

The reagent bottles have 24 drops per ml. That means the:

• 0.75 ounce ("A" size Taylor) bottles has 532 drops
• 1 ounce TF100 bottles has 710 drops
• 2 ounce ("C" size Taylor) bottles has 1420 drops.

Testkit Taylor k-2006 vs. k-2006C vs. TF-100 (bottles, OZ)

Hello, I am making my final research for buying the first test reliable kit for ourselves, so once it arrives and we test it, we can start ordering more (little kits for now, could be up to 5 max at once). Made some research on the FAS-DPD test kits and have one, maybe, technical question that...

www.troublefreepool.com

 

[convan23]

FYI switched out the tips with some other bottles and now I’m getting identical readings with both sets of reagents. Hooah.

If I wanted to buy more tips from like Amazon, what’s the search term? Or could I reach out to TFTestKits and buy some from them you think?

 

[revitup]

None of this is inspiring confidence in test accuracy or quality control.

 

[Dirk]

None of this is inspiring confidence in test accuracy or quality control.

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.

 

[newdude]

#1.

Especially here with what appears to have been a clogged bottle tip. I'm happy it was easily fixed but I'd expect the occasional unrepairable tip from the molding process. It's so small and they churn out bazillions of them for fractions of a penny each.

So this wasn't a Reagent inaccuracy, it was a mechanical failure.

Everything has some variance to it in any testing situation. In our case, for what we need to do, good is GREAT.

 

[Bperry]

FYI switched out the tips with some other bottles and now I’m getting identical readings with both sets of reagents. Hooah.

If I wanted to buy more tips from like Amazon, what’s the search term? Or could I reach out to TFTestKits and buy some from them you think?

So that means the new reagents are reading lower now or the other way around? Was curious if the plaster polishing led to some kind of calcium leeching into the water.

 

[convan23]

@Bperry it appears that this was 100% a tip error like what @Newdude said in the post above. It sounds like the bottle tip was more restrictive and letting less reagent out per drop.

Before replacing the tip, the new reagents were showing 625+ on the CH scale. After replacing the tip, the same reagents are coming out to around 450.
I have verified the 450 reading with a second set of Taylor reagents.

So, I'm confident the 450 CH reading is accurate, and I had some bad tips. It's a bummer because if I didn't have these existing reagents I wouldn't never known better.

I'm noticing something similar with my TA Readings being higher now then I'd expect them to be...I didn't think too much of it initially since my existing TA reagents are actually a lot older and I've noticed that I seem to have to use more muriatic acid then what pool math tells me for a specified PH change. So I had some suspicion that my TA might be higher... However, I did swap out the tips on the TA bottles with some other tips I had and also noticed the reading dropped from 100 to 90... I'm not 100% confident yet those tips were bad as I haven't done enough testing to verify that. I don't want to start some sort of criticism on TFTestKits (sure same thing can happen buying straight from Taylor). Still happy with their service+price point and will continue to buy from them.

 

[newdude]

I'm noticing something similar with my TA Readings being higher now then I'd expect them to be..

Read the test card and folloe carefully for TA, it is well explained for new bottles.

They get a static charge in shipping and need to be wiped between each drop. After so many tests, (5-10 ?) it's normal again and you don't need to wipe.

 

[pookiesunshine]

@Bperry it appears that this was 100% a tip error like what @Newdude said in the post above. It sounds like the bottle tip was more restrictive and letting less reagent out per drop.
.....

Can you see the difference in the old and new tips? or is the difference so small you can tell only by testing? Glad you solved your problem.