Salt Water Test Trips vs Automatic Read Out

[TAMC93]

We just started the SWG yesterday and I was going through weekly tests:

Strips (From TFP): 1300 ppm
Hayward Readout: 2900 ppm

I tend to believe the readout, but why are the strips so far off?

Rest of Results below (prior to any adjustments):

6/22/2013 8:30
PH 8
FC 8.5
CC 0
TC 8.5
TA 90
CH 80
CYA 60
SW 2900

Notes: SWG Installed 6/21/13
Add 32 oz. Muriatic acid
Add 40 lbs. Salt
Added 24 oz. of Stabilizer

 

[Patrick_B]

Assuming your strips are fresh and I'm guessing they are, I would trust them first. What was your salt before you added the 40lb?

 

[JasonLion]

It is more likely that the SWG is correct, though it could go either way. The only common situations where the SWG are wrong (scaling and cell wearing out) all result in lower than actual readings.

The test strips are usually quite good, but for some people they are way wildly wrong. They are also very sensitive to being exposed to moisture before being used.

 

[TAMC93]

The strips are just opened (received 2 weeks ago) and the SWG is brand new.

I went with the SWG reading and added salt. Based upon the "taste test", it would appear the SWG was closer to being accurate.

I will retest with the strips tomorrow and compare again.

 

[TAMC93]

The strips are just opened (received 2 weeks ago) and the SWG is brand new.

I went with the SWG reading and added salt. Based upon the "taste test", it would appear the SWG was closer to being accurate.

I will retest with the strips tomorrow and compare again.

Todays results -
Strips - 1,900
Auto Reader - 3,500
and still "tastes like salt"....

Also - since I was circulating on a low flow setting the SWG spike the FC to 13.5. Guess it is working and I am reducing the percentage. Good to note in the future...

 

[Patrick_B]

Good for you. Whatever the reason, those are some lousy strips I guess.