Just got new TFT test kit - TA test shows double

DougS

Gold Supporter
Bronze Supporter
Oct 7, 2015
29
Pleasanton, CA
#1
Hi,

I just purchased the TFT test kit and now I'm getting twice the reading on TA. It was about 70, but it's now reading at least 150. I retested with the Leslies test kit and confirmed that the results are double with the new kit.

Could it be a problem with the new test kit? Or the old?
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
41,197
Tucson, AZ
#3
New TA reagent tends to have static build up so the drops jump prior to being full size. Like Dave asked, did you wipe as the instructions state?
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
31,333
Sebring, Florida
#5
Yeah, that will catch some of it but not all so there's more going on. I suspect your old reagent is going south and I would always trust new stuff over the old.

By way of explanation, when the R-0009 is really fresh, it somehow generates static electricity between itself and the dropper tip and causes the reagent to "jump" off the tip (forming a too small drop) rather than falling naturally. It's a short-lived phenomenon. About the biggest discrepancy I have seen is maybe 50% but certainly not double.

That's why I would be suspicious of the old reagents and trust this fresh, new kit you have.
 

DougS

Gold Supporter
Bronze Supporter
Oct 7, 2015
29
Pleasanton, CA
#8
Update:

I took off the tip from the R-0009 bottle and noticed that the hole was very tiny (smaller than the other reagent bottle tips). So I took a safety pin and reamed the hole out just a bit and then retested. The drops are now bigger than before (not quite as big as the drops from my old R-0009 kit), so the new TA test is now reading about 90 (vs. 60-70 with the old kit).

Question: Since the tips in the other bottles (R-0007 and R-0008) seem to produce larger drops, should I just switch one of them out with the R-0009 bottle?

Or, should I ask for a replacement of the R-0009 bottle?
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
41,197
Tucson, AZ
#9
The hole size should not really impact the drop size. The drops should hang on the tip and then fall when fully formed.
 

DougS

Gold Supporter
Bronze Supporter
Oct 7, 2015
29
Pleasanton, CA
#10
The hole size should not really impact the drop size. The drops should hang on the tip and then fall when fully formed.
Well in that case, the drops are slightly larger than before (after I wiped and messed with them), but still not as large as the drops from the old kit or the other reagent bottles.

Should I ask for a replacement bottle?
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
31,333
Sebring, Florida
#12
There is only one type tip that fits all those bottles. Email TFTestkits and they will cheerfully send you another one but it won't make any difference.

The size of the tip does not control the drop size. The drop forms on the rounded tip surface and gets larger and larger until gravity takes over and it falls.

Personally, I would accept you new reagent as accurate.....the 20 ppm difference could be attributed to several variations but I'll bet the new stuff is accurate.
 

DougS

Gold Supporter
Bronze Supporter
Oct 7, 2015
29
Pleasanton, CA
#13
Thanks Dave,

I'll live with this one for a while and monitor results. It never really made sense to me that my TA was so low (40 was the lowest), so the higher reading from the new test kit makes more sense. But my low readings led me to add baking soda (not very much) about a month ago. Anyway, since the new test kit shows TA of 90, I'll consider it accurate, and possibly on the high side.

I think you recommended that TA should be in the 60-80 range for a salt pool, so I'll monitor.

Other readings today were:
FC - 5
PH - 8.5
CYA - 40

I added 1 lb of conditioner over the past 24 hours, so I'll see if it bumps the CYA reading. Thanks for all the help.