Overshot FC during Slam - how??

[AngelaKelly]

This pool season has been a doozy for us - winter leak, hard opening (successfully completed slam), broken laterals in sand filter, SWG died, and now performing another slam after noticed slippery floor and failed OCLT on Saturday.

I tell you all this because this forum has been so helpful! Here’s what I need to know now. I posted pics of my test results to show the timeline - earlier today my FC was at 25, added the recommended pool math FC to get it to proper slam level. Tested again and FC jumped to 40!

It’s important to add that my R-0871 reagent was low the other day so I ordered a new one which arrived today. My 25 test before adding chlorine was with my older (but not expired reagent) which ran out on that test and my 40 test was with my new reagent.

My questions -
1) Is this high level of FC harmful? It is supposed to be sunny tomorrow so it should drop.

2) Could the reagent change impact the test results?

3) Why the jump if I followed pool math’s suggested amount?

Any help and insights would be appreciated! Thanks!

 

[PoolStored]

Oh lord. We are having a thread between the mods/guides/experts on this issue.

There is a static buildup in the reagent bottle plastic, likely from the bubble wrap shipping material, or handling. The static makes the droplet size smaller, giving larger results.

Do the test again. Evacuate a bit of air before you invert the bottle. Wipe the tip with a wet coffee filter or paper towel, then complete the test.

Report back.

 

[AngelaKelly]

Oh my goodness, thank you! Appreciate the quick response!

 

[AngelaKelly]

To keep accurate information on the forum - just wanted to let you know that I did exactly what you said, tested again, and I’m at my SLAM FC level of 28. Pool Math and this forum nailed it again - thank you!!

 

[PoolStored]

 

[DrewLG]

Wipe the tip with a wet coffee filter or paper towel, then complete the test.

And for anyone who reads this in the future: According to Taylor, it's ok (and effective) to wipe AROUND the tip, but you should avoid wiping OVER the tip -- as doing so can deform or damage the tip, which might then permanently alter the drop size.