Rookie TF-100 Question

Marcm15

Active member
Jul 1, 2010
41
Orange County, NY
I received my TF-100 and all tests went well except for the CYA, which I had to run twice I believe due to my incorrect interpretation of the instructions. The instructions state to hold the view tube at waist level, so you can look down into the tube and add the pre-mixed solution slowly until the black dot is totally obscured. The first time I looked directly down into the tube from the top and of course the black dot was never obscured in the clear solution. Common sense then kicked me in the Rear and I repeated the process but looked through the tube still at waist level but on an angle and came up with a result of 60.

Can someone please just let me know if I conducted the test correctly the second time? I know there is no such thing as a dumb question but this just seems so simple I was almost embarrassed to ask.

Thanks for all the help and encouragement. I already suffer from OCD (as diagnosed by my wife and kids) and now with the addition of the new pool, I am starting to agree with them!
 

benavidescj

LifeTime Supporter
Apr 27, 2010
431
Fleming Island, FL
Not a dumb question at all since the CYA test is one of the hardest to interpret and has a high error rate of + or - 10 at best. The way you did it the second time sounds right.
 

anonapersona

TFP Expert
LifeTime Supporter
Nov 5, 2008
2,598
Straight down is correct, you need to look THROUGH the entire tube. If the solution was clear, then your CYA was 0.

Was this pool recently filled? Tap water will have no CYA. If you've had the pool filled for some time, then what sort of chlorination have you been using? "Stabilized chlorine" in pucks or dichlor "powder shock" will add CYA. If the pool has been up over the winter it may be that CYA fell to 0 over the winter, or maybe there is some CYA left from last years usage of pucks or dichlor shock.

One tip off, how is FC holding over the course of a day? If you start the day by adding bleach to 3 ppm, is there any FC left at 6 pm on a sunny day? If CYA is 0 the answer is probably FC = 0.

Also, start a Pool Book. In it record all the tests as you do them, then what you add to the pool and what results you expect from the chemicals. Add all the important things you know, like pool specs and age of equipment. Also record things you need like phone numbers of stores that sell pool stuff, Walmart, Home Depot, Lowes, Sams/Costco, local pool stores and keep a list of their prices for stuff you consume like bleach or liquid shock, stabilizer(CYA), pucks or powdered shock and exactly what brand and ingrediants are for those, etc. Add notes of stuff you learn here.
 

Marcm15

Active member
Jul 1, 2010
41
Orange County, NY
The pool was filled for the first time on July 1st of this year using municipal water. I have been keeping a log of my test strip readings. Today was the first try with the TF-100. So If I understand you, I should be looking straight down through the open top of the cylinder? The solution did remain clear when I added the reagent. What color change should I have seen if there was any CYA in the water?
 

Marcm15

Active member
Jul 1, 2010
41
Orange County, NY
Water is crystal clear. I have been using Dichlor 3 inch tablets. I did use a granulated shock product by HTH upon initially filling the pool but not since. I haven't transitioned to the BBB method yet. I just received my test kit yesterday. The results I received are as follows:

FC - 1.5

CC - 1

TA - 120

PH - 7.2

CYA remains unknown until I confirm the correct way to run the test.
 

Melt In The Sun

TFP Expert
LifeTime Supporter
Oct 29, 2009
3,899
Tucson, AZ
Sounds like you're running it correctly (equal parts CYA reagent and pool water well mixed, dribbled into the tube til the dot disappears when looking down through the top of the tube).

You just haven't added enough stabilizer to the pool for it to show up in the test. I suggest getting some powdered stabilizer and adding enough to reach 30 ppm.
 

anonapersona

TFP Expert
LifeTime Supporter
Nov 5, 2008
2,598
If you can figure out how many of the 3 oz pucks you have used, either a number per week or some fraction of a weighted bag, that will give us a way to estimate what CYA might be there now. For example, 10 3oz pucks of dichlor will give you a CYA of 11. Today being the 9th, and CYA taking a week or more to show up sometimes, means that you could have something like CYA of 10 now. That is very hard to see on test. However, if you add for CYA 30 and end up with CYA 40 that is fine.
 

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