Over night drop test after SLAM.

[MJuric]

So I opened the pool and followed the SLAM process.

Water is clear CC is lower then .5 but for the life of me I can't seem to get repeatable numbers on the chlorine test to verify how much I drop over night. Seems like I can do the test 2-3 time in a row and get different numbers. The directions say no drop more then 1 PPM over night and I can test three times and get 3-4 PPM differences.

What I was thinking was that since I'M at slam levels it will take very little additional water, not really measurable with the beaker, to get these variations. So my plan is to allow the chlorine levels to drop to normal levels and then do the drop test. I just tested now with the regular test kit and it looks like I'm around 4 PPM. I'm assuming if I test in the AM and that I'm still at 3-4 PPM I'm good to go. If I'm at 1-2 or lower I need to raise the levels back up to SLAM levels.

Am I on the right track here?

Thanks,

Matt

 

[Richard320]

If you go up to the 25 ml sample, half a ml of water off won't have quite the same effect. Run the test the same, but multiply by .2.

 

[MJuric]

Clearly I'm doing something wetting here. Did the 25ml test 2x in a row. 72 drops once 92 drops the next time.

Got water level as close as possible on each test.

How important is the amount of the powder reagent put in? The "scoop" I use is FAR from accurate, but I was under the impression the amount of that reagent didn't matter.

 

[duraleigh]

The amount of powder doesn't matter. If the solution turns pink, you have enough powder.

Do you understand the endpoint of the test?

Are you taking the sample about a foot deep or more into the water?

Is your pump running and circulating the pool water 30 min or so before you test?

Are your procedures (taking the sample, swirling completely) done correctly?

The FAS/DPD test works. It is accurate and precise even with a 10 ml sample. Please reread the directions very carefully. Somewhere in there is something you are missing.

 

[MJuric]

I will go thru the instructions again. This is what I'm doing however. In case something looks glaringly wrong.

1) rinse vial.
2) Fill vial, 12-18 " deep.
3) pour out excess to level, typically till bottom of bubble hits line.
4) add 1 scoop of powder.
5) add drops until water is clear.

Pump is running 30 plus minutes before. Sample is taken 12-18" below surface. Samples are taken in same spot in pool.

 

[duraleigh]

Just a little adjustment to your steps. Add drops until the LAST drop you add makes NO further color change....none. Then subtract that last drop and the result is your total.

That test is typically so precise that you never need to check it twice but I understand you need some clarity.

https://www.youtube.com/user/tf100testkit?feature=results_main This video takes just a minute or two and may help....just double check yourself.

Take a deep breath and do the 10 ml test once more. Then do it again. If you get a different result, split the difference and move on.

 

[MJuric]

I'll watch the video and try out again. Thanks all for the help.