Hi, just got a new 300 gal spa and first time owner. So, followed the pool store directions for water chemistry and all measures are within norms on the test strips, except free chlorine which goes back to 0 every day. So, every day for the last 5 days I have added about 1/2 TBSp of dichlor which gets it back to around 3ppm (we do have 250 reading for phosphate). Concerned about the CYA levels, I bought a Taylor K2006 kit from Amazon. However my first time with this kit, it shows 10ppm in FC but the test strips indicate 4ppm. I can understand a little difference but this difference is huge and I don’t know which one to believe. I did the Taylor DPD test 3 times and same result. Is it possible the test kit is a fake? Are test strips really that bad? Really not sure what to do here, any advice appreciated thanks!
Test strips difference with Taylor k2006 kit
- Thread starter recordlevel
- Start date
- Jul 21, 2013
- 64,855
- Pool Size
- 35000
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- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Welcome to TFP.
Yes, test strips are really that bad.
Believe the fAS/DPD FC test. That is what we recommend.
Yes, test strips are really that bad.
Believe the fAS/DPD FC test. That is what we recommend.
Last edited:
- Jun 24, 2021
- 15,655
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
Your K-2006 is the Gold Standard for testing. Trust it.
- Jun 1, 2018
- 15,974
- Pool Size
- 26000
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- Vinyl
- Chlorine
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- Hayward Aqua Rite (T-15)
The test strips are just generally bad and they also are susceptible to getting bleached out by higher fc levels.
Stick with your Taylor kit for accuracy as recommended above.
*Also note that for every 1ppm of fc that dichlor adds it also adds nearly 1ppm of cya.
Once cya reaches 30/40 ppm you should switch to liquid chlorine or following the proper FC/CYA Levels becomes increasingly difficult.
You always need to keep fc above minimum for your cya or nasties will proliferate rapidly in a spa environment.
Here’s the guides for using chlorine in your tub.
Long version
www.google.com
Short version
www.troublefreepool.com
Stick with your Taylor kit for accuracy as recommended above.
*Also note that for every 1ppm of fc that dichlor adds it also adds nearly 1ppm of cya.
Once cya reaches 30/40 ppm you should switch to liquid chlorine or following the proper FC/CYA Levels becomes increasingly difficult.
You always need to keep fc above minimum for your cya or nasties will proliferate rapidly in a spa environment.
Here’s the guides for using chlorine in your tub.
Long version
How do I use Chlorine in my Spa or Hot Tub?
If you have a question about any information within this Sticky, please start a new thread for yourself where you will receive very quick responses to your specific questions. Thank you! Introduction There are two main things to consider when maintaining your hot tub water, Water Balance and...
www.google.com
Hot Tub Basics - Further Reading
www.troublefreepool.com
- Jun 1, 2018
- 15,974
- Pool Size
- 26000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
You can use
PoolMath effects of adding to calculate how much cya your dichlor doses have already added.
I do it each time I add dichlor and list my calculation as my cya test result in the log as I go until I have it high enough to actually test for it.
PoolMath effects of adding to calculate how much cya your dichlor doses have already added.
I do it each time I add dichlor and list my calculation as my cya test result in the log as I go until I have it high enough to actually test for it.
Thank you so much for the quick replies and for the help. I did a little control experiment and then contacted Taylor. I added a small amount of Dichlor to regular tap water and got the concentration to 3ppm according to the test strips. The Taylor DPD test registers about the same amount. SO, that suggests there is something interfering with the test in my spa water. Turns out Oxy shock can cause interference in the DPD test, and I had used sodium Peroxydisulfate - they believe this is likely causing a skewed result. They do have a separate test kit that is not affected by potassium monopersulfate, which I guess is a more common one.
- Jun 24, 2021
- 15,655
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
You indicated that you used Dichlor...not Oxy Shock. Would have been helpful to know. I guess we should have asked what else you added.
- Jun 1, 2018
- 15,974
- Pool Size
- 26000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
There is a special interference reagent.
However, in general mps (non chlorine oxidizer) is not really necessary for a properly chlorinated tub.
Chlorine is both an oxidizer and a sanitizer.
While Mps is only an oxidizer.
Why use both & deal with the complication when adequate chlorine alone will do the job.
Mps is also a known irritant so many just avoid it.
Makes life simpler.
However, in general mps (non chlorine oxidizer) is not really necessary for a properly chlorinated tub.
Chlorine is both an oxidizer and a sanitizer.
While Mps is only an oxidizer.
Why use both & deal with the complication when adequate chlorine alone will do the job.
Mps is also a known irritant so many just avoid it.
Makes life simpler.
Thanks. Yes The dealer recommended adding Oxy after each use of the tub, and I was wondering if that was really necessary or just to sell more chemicals. Good to know!
- Jun 1, 2018
- 15,974
- Pool Size
- 26000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
I have never used it in 6 years of chlorine hot tub ownership & 12+ years of chlorine outdoor pool ownership. In my opinion it’s really not necessary in those instances.
Adequate Chlorine has always been enough for me.