FAS-DPD test

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J

Jamann

0
Jun 10, 2017
20
Elk Grove, CA
Morning folks, just a quick question... when performing the fas-dpd test (tf-1000), do you really
multiply of drops by .5? I'm coming up with a pretty crazy number if so. I have read the instruction and watched Taylor's instructional to ensure I am performing the test properly, and am coming up with 33ppm...
 
Little background-- just bought a home, first run of the numbers yesterday. During the inspection the inspector said it needed help; but I didn't expect it was this bad. The numbers are as follows:

[FONT=.SF UI Text][FONT=.SFUIText]Fc-33ppm[/FONT][/FONT]
[FONT=.SF UI Text][FONT=.SFUIText]CC-1[/FONT][/FONT]
[FONT=.SF UI Text][FONT=.SFUIText]Cya-200+[/FONT][/FONT]
[FONT=.SF UI Text][FONT=.SFUIText]Ph-6.8[/FONT][/FONT]
[FONT=.SF UI Text][FONT=.SFUIText]Ch-625[/FONT][/FONT]
[FONT=.SF UI Text][FONT=.SFUIText]Ta-90

Bear in mind I am quite the novice, so these may be slightly off...

as for the FAS test, it was a 10ml sample, took 66 drops to go clear. [/FONT][/FONT]
 
Jamann, now that you're testing your own water, I can tell you this .... everything you do first hinges on that CYA. A CYA over 90 becomes almost impossible to manage. But to be sure, try the CYA diluted test method as noted on the TFP Pool School - CYA page, starting at Step 8. Let us know what you get. The only way to lower CYA is by water exchange, or at least a good chunk of it. There's no sense wasting ANY other chemicals on anything right now until the CYA is confirmed to be much lower under 90. Keep in mind the CYA probably got that high from pool store products used by previous owners. Items like Chlorine tabs/pucks, bags of shock, etc used continuously. If they are still there, remove them ASAP. Regular bleach is the best way to increase free chlorine to the water. Work on that CYA first and let us know what you get.
 

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Actually, I think with a cya of 200+, 30ish would be right in range.

But yeah, you need to lower your cya to about 50 by draining water. If you have a vinyl liner pool, you'll need to do it in stages as you'll likely have to drain quite a bit. What's the condition of the water? Clear, cloudy, green, swampy?
 
I have a question on the FAS-DPD test. Is this the most cost effective way to test chlorine levels on a daily basis ? I have been using this test for the past two years and it seems like I am going through a lot of reagent. Should I switch to using a 25 ml sample instead of a 10 ml? I typically use two scoops of the FAS-DPD powder when testing. Thanks :)
 
You can use a 5ml sample, with one scoop of powder. Then each drop would count as 1ppm. If you don't need as much accuracy.

I use the oto test for regular testing... My minimum chlorine need is 4 so I want it to be darker than the darkest color (5pp). Some people say that doesn't work, but I've had no problem in 3 seasons.
 
Fingaling said:
You can use a 5ml sample, with one scoop of powder. Then each drop would count as 1ppm. If you don't need as much accuracy.

I use the oto test for regular testing... My minimum chlorine need is 4 so I want it to be darker than the darkest color (5pp). Some people say that doesn't work, but I've had no problem in 3 seasons.
Click to expand...

The problem with the OTO test is that it doesn't differentiate FC from CC. It only measures TC. So, you could easily have 2 FC and 3 CC, or any combination and not know it. Just FYI...
 
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