Test Numbers Test Strip & Drop Test

Rockcrawler

Well-known member
May 8, 2007
174
El Paso, Texas
#1
Thought I would run my numbers through you guys and let me know what you think? I know the strips are not reliable, according to all the forums, (wonder why they still make them). I bought them before I joined the forums, so I thought I would include them as well, and yes as you can see there are some differences

Test Strips

TH 400
FC 0
CL 3
PH 7.5
TA 120
CYA 30-50

HTH Test (new)

TH 600
FC 0
CL 3
PH 7.5
TA100
CYA 70

as you can see the only real difference is the TH and CYA


I know I have to add clorine because I have none, and I know my CYA is high according to the HTH kit, my real question is, because my CYA is high, if I add more clorine wont it be too high to swim????

I am using liquid clorine (bleach) for my sanitizer, I have puck and shock granules, but will be waiting to use them until my CTA and Hardness goes down some

I know this is kinda long sorrry
Thanks
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,082
San Rafael, CA USA
#2
If your CYA is truly at 70 ppm then the min/max FC range for your pool is around 5 to 10 ppm. This corresponds to a disinfecting chlorine level of 0.03 to 0.07 ppm and is equivalent in disinfecting and oxidizing power to having 0.07 to 0.14 ppm FC in a pool with no CYA. So you are very, very safe in a pool with 10 ppm FC when it has 70 ppm CYA in it. Consider that most indoor pools have at least 1-2 ppm FC and have no CYA and you can see that they are far more "dangerous" with regard to disinfecting chlorine level.

The only danger to a high FC with high CYA is in drinking the water since then it is the FC that is important since it is the total amount of chlorine available and that will be released from the Cl-CYA "bound" chlorine over time (as the disinfecting chlorine gets used up). Even so, it would take drinking quarts to gallons of pool water every day to even start to be a problem. It might be more of an issue for a dog that drinks about a quart of pool water every day.
 
G
#4
Rockcrawler said:
Thought I would run my numbers through you guys and let me know what you think? I know the strips are not reliable, according to all the forums, (wonder why they still make them). I bought them before I joined the forums, so I thought I would include them as well, and yes as you can see there are some differences

Test Strips

TH 400
FC 0
CL 3
PH 7.5
TA 120
CYA 30-50

HTH Test (new)

TH 600
FC 0
CL 3
PH 7.5
TA100
CYA 70

as you can see the only real difference is the TH and CYA

Thanks
This is reason enough why the strips are not precise enough for water balancing! Also, If you look at the pH range on your strips it ususaly will have a jump from 7.2 to 7.6 or even 7.8! This is a big jump and a change of just .2 in pH can have a big impact on water chemistry!
Strips are fine for a quick daily check to see if you are in the ballpark (I use them for this purpose myself) but not for water balancing and adjusting! If your quick daily check with strips shows the water is out of whack then pull out the drop kit and test with that!