Will temperature of R-0013 affect CYA reading?

CoolHome

Well-known member
Jun 6, 2020
50
Crawfordsville, IN
I am still struggling with the CYA test. When I first put stabilizer in the pool I measured with a goal of 40ppm. However, I was using 6000 gallons, the capacity of my pool and it was not completely full. So when I first tested and was getting 50-60 I figured that was why. I've since filled the pool to capacity and got a new sand filter, which had to be back washed several times at first to finally get my water truly clear, so I was having to replace that water for two or three days. The other day I noticed that my FC levels were seeming to fall a lot during the day, so I double-checked my CYA and it was showing 40. I figured that with the extra water and having to replace some from backwashing it must have brought the CYA levels down, so I backed off on the chlorine. While I was at the low end by the end of the day (hot sunny days, 2-3 people in the pool for 2-3 hours a day) it wasn't dropping as much. Figured I got the CYA dialed in, but since the 40 reading was new I decided to double-check it. The first test I got 60 again! Did it a few times got 60 each time. So started over with new reagent in case I'd messed up ratio. Now I was getting 40 (I could almost pour to the 30 mark before it disappeared). I tried this 4 times with new reagent (trying each test 2-3 times before changing mixture). Was getting the same thing 40, each time. Ok, figured the first test was a fluke. Decided to try again today since it was sunny, just wanting to have it confirmed the first time, instead I got 60 again.

I realized that what was changing between the readings was that both times I got the higher number I was using the reagent in the dropper bottles. The lower numbers was when I had to refill the droppers with fresh reagent from my larger bottle I keep in the closet. Now all of this reagent is kept in the house but the test kit goes outside for short periods. I'd refilled the dropper bottles to make it easier to pour in (the large bottle has no dropper) and to have it with the rest of my test kit. Could the fluid from the big bottle be being contaminated sitting in the older small bottles? Or could the temperature of the smaller bottles be getting warmer affecting the reading? I'm getting so sick of this test. 40-50 or 50-60 is no big deal but if its somewhere between 40-60 I pretty much have to treat it likes its 60 to be safe and feel like I'm just wasting chlorine, especially because it seems to fall quickly from the higher FC levels. Should I just trust the "fresher" tests?

Current levels

FC 6
CC 0
PH 7.4
TA 150
CH 260
CYA ???
 

Wobblerlorri

Bronze Supporter
Try this. Fill the viewing tube to the first line at the bottom. Glance for the dot. If you see it, fill to the next line and glance for the dot. Keep filling to a line and glancing until you can't see the dot at a glance. This method made the test SO much easier for me to read! Takes care of those nasty in-between readings, too.
 

CoolHome

Well-known member
Jun 6, 2020
50
Crawfordsville, IN
Try this. Fill the viewing tube to the first line at the bottom. Glance for the dot. If you see it, fill to the next line and glance for the dot. Keep filling to a line and glancing until you can't see the dot at a glance. This method made the test SO much easier for me to read! Takes care of those nasty in-between readings, too.
Thanks Wobblerlorri, I do, do this. I agree it makes it easier. I've read everything I can find about how to perform this test properly (back to the sun, hold waist high, glance, make sure water isn't too cold). I'm not getting variations between the same mixture. It's happening on totally different tests and its a large, obvious difference. I can almost pour to the 30 mark before it disappears on one and it's completely clouded right after I pass the 60 mark on another. Its got to be another test error somewhere, but I'm controlling for everything I can (where I take the water, where the sun is, how balanced the water to reagent mix is, time of day) it seems to be something with the reagent itself that is throwing it off. Either I've contaminated it by putting it in the older bottle or it's a temperature thing, that's all I can think of.
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
34,283
Sebring, Florida
Frankly, you are wa-a-ay overthinking this test.

First it is accurate to plus or minus 10 at best perhaps 15 + or - is more likely.

So, mix per the directions, pour the mixture in the tube and look to see the dot.

If you don't see the dot (regardless of ALL the other tips and tricks) pour some back into the mixing jar until you DO SEE the dot in the view tube. Next, add in small increments back into the view tube until you are pretty sure you DON'T see the dot. That's your CYA result.

Now, to reassure yourself, pour it all back into the mixing tube and do the exact procedure again.......you'll get pretty close to the same results.

You are welcome to do that as many times as you like but I'll bet you get pretty darn close on the first two.

With only one reagent to blend with the pool water, a testing error is pretty difficult to make.

The reagent is inert and remains chemically unchanged for years.
 

CoolHome

Well-known member
Jun 6, 2020
50
Crawfordsville, IN
Ok, thanks. I do get the same reading over and over with the same mixture. Its just that the next time I do it (with a fresh mixture) it will be 20+ lower or higher. Oh well. I'll just continue to use the higher number to set the goal and try to quit being annoyed by it!