Riddle me this…

[sniklas]

I’m day 11 into SLAMing (don’t ask…this will be the ONLY time I let this happen). CYA 40 = FC 16. Done, tested and maintained 3x/daily.

Woke up this morning, pre-dawn, FC @ 15.5 and CC @ 0.5 (my pool always seems to run CC @ 0.5, even when crystal clear). I’ve been running the test twice, with a sample from both (long) sides of the pool (away from skimmers, returns, etc.) I left it and decided I’d check and adjust again when I get home.

Get home, still light out but sun under the horizon. FC at…16.5??? Again, two tests with samples from each side of the pool. NO chemicals were added. I have a SWCG but it’s completely off and has been since I started SLAM.

Any smart, astute pool people have an idea why FC would rise 1 ppm without chemicals being added or the SWCG off? I have an auto-cover, it was closed all day (high was 67° today). Water temp being maintained at 86°. Don’t know if either of those data points matter I’m certainly perplexed, and this is the second time it’s happened during SLAM.

 

[Mdragger88]

Was the pump running all night? If not, try doing that.
Had you had coffee? It’s early & thats alot of drops to count
Just do 1 test from the same place every time & call it.
The cover will trap cc’s so open it when you can to let them out.
Also- clean your test tube with alcohol.

 

[sniklas]

Was the pump running all night? If not, try doing that.
Had you had coffee? It’s early & thats alot of drops to count
Just do 1 test from the same place every time & call it.
The cover will trap cc’s so open it when you can to let them out.
Also- clean your test tube with alcohol.

I’m before coffee no doubt! But no, I got the same result twice. I’ve only been testing two samples since the need to SLAM arose, I know it’s unnecessary and overkill. In cases like this, though, it helps me know that, no, im not actually going crazy and yes, I’m still able to count.

Pump runs 24/7 when the pool is open, that’s how I’ve operated it from day 1. 50 gpm normally, 60 gpm when the heater is running.

Ahhh, duh! How often the cover is opened makes perfect sense with the continuous 0.5 CCs. Hadn’t thought about cleaning the test tube with alcohol…I rinse it, the “X” (as my toddler calls it), and the glass I use to sample with tap water each time and manually dry with a clean paper towel. I’ll give that a shot, thanks again!

 

[pjt]

the glass I use to sample

Don't have glass in or around the pool. A plastic condiment dispenser works great for your water sample, and costs ~$1 at Walmart.