New pool owner and first test results from my test kit

Human related drop size disparity is probably the biggest source of error in testing, especially dropping too fast and forcing the drop off, rather than letting gravity rip it away slowly. So good thinking.

In this case, using 10mL, the SLAM ending criteria were all met at the same time, and since then I believe the factors resulting in some confusion were higher FC loss due to lower than ideal CYA for that FC level and July weather conditions.

You're correct that the 25mL is an option, and that consistent dropping is essential for either test to produce a valid result. In most cases, the 10mL sample is sufficient, and I believe that's the case here.
 
25ml test would be brutal on reagent use at that FC level, lol. Three tests would probably kill a 2oz bottle.

I was very careful when counting drops. But over the course of 60+ drops, as said, the disparity between them probably comes into play.

I would have preferred an even smaller sample size while SLAMing to cut down on reagent use. Even something like 1 drop per 1 FC. I don't believe resolution is as important when just trying to maintain a large amount of chlorine throughout a SLAM. At least not until it's time to do the OCLT.
 
I did a slam at 25 for some measurements. There is a surprising number of drops in there.

However, this may be the way to go once FC has dropped to 1 or so.

Also, slamming at 5ml sample size does what you want. Probably a good recommendation for those slamming at high CYAs.
 
25 ml= 5 drops/FC
10 ml= 2 drops/FC
05 ml= 1 drops/FC

More accuracy and precision higher on the list, less accuracy and precision lower on the list. (And obviously less Reagent lower on the list)

So the short answer is yes. :)
 
25 ml= 5 drops/FC
10 ml= 2 drops/FC
05 ml= 1 drops/FC

More accuracy and precision higher on the list, less accuracy and precision lower on the list. (And obviously less Reagent lower on the list)

So the short answer is yes. :)


Awesome, thx! Good to know.

So I just tested my FC/CC. It's 6pm so it's been 12 hours since the last test. The pool has been sitting in direct UV and today got decently hot into the low 90s. FC dropped from 32ppm to 26.5ppm. I assume it's normal to see decent FC loss when you're that high above your target and the pool has been sitting in direct sunlight? I'm planning to do a backwash and refill in a couple hours then retest awhile after that to set a baseline for tomorrow morning's OCLT.
 
I don't like doing OCLT the same day as municipal water add, since it does have chloramines (CC) that FC will try to oxidize, even though the UV will do it for free the next day lol.

If you fail this OCLT, no big deal IMO, redo OCLT after a day of sun. If you pass, your pool is extra special healthy!
 
Also good to know! Thx! Although, ironically, the last time I did a backwash and refill is when I passed the OCLT with a .5ppm FC loss. lol

While I was backwashing and the returns weren't churning up the pool surface I took a pic as it looked so nice and clear...

945976cc13ac5bd.jpg


I dropped a good 2" of water out and re-filled up with 3". Slowly but surely I'll get rid of that extra CYA. :D
 

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That really looks TFP clear to me! Those are some mighty clean drains you have there! Nice brushing! Great job, let fall to target. Retest CYA whenever you get down to around where you expect target to be (since you'll need to know current CYA to know target) no point in testing before you're close though.
 
Also good to know! Thx! Although, ironically, the last time I did a backwash and refill is when I passed the OCLT with a .5ppm FC loss. lol

While I was backwashing and the returns weren't churning up the pool surface I took a pic as it looked so nice and clear...

945976cc13ac5bd.jpg


I dropped a good 2" of water out and re-filled up with 3". Slowly but surely I'll get rid of that extra CYA. :D


You were so CLOSE! Why did you empty out all the water? And how are you getting your liner to stay flat with no water in there? ;-)
 
So maybe you guys can help me identify what model of sand filter I have? With the house paperwork came the manual for mine, but I'm not sure the actual model. It's a generic manual for a whole line of filters. It's a Sand Dollar brand filter I know for sure based on the manual but there is no label on it anywhere.
 

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11 hours later at 5pm and FC is only down to 19ppm. CC is zero. That's only 2.5ppm used with the pool sitting all day uncovered in the mid 90's hot sun. It might be a couple days before I can accurately test PH again, lol. I also tested CYA and it's down to 80ppm. I have the 50ppm CYA reference coming in the mail so I can make sure but I'm pretty confident it's 80 as on the line I can still just barely make out the dot.

Should I wait to swim until I can test PH?
 

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