New Pool Owner - First Full Test Results

[jimmyz80]

I've been lurking on the board for about six months now, ever since we bought this house that came along with the pool described in my signature. Really appreciate the wealth of information! So far I've been using a pool guy to maintain the pool chemicals, and I've been trying to learn as much as possible to eventually start maintaining the pool myself. Today I did my first full set of tests with the TF-100 kit I picked up.

pH: 8.2 (off the chart)
FC: 14ppm
CC: 0ppm
TC: 14ppm
CH: 150ppm
TA: 70ppm
CYA: 27ppm
Salt: 3400ppm
Temp: 72F

Some thoughts and background on a few of the numbers above:
- The pool had been consuming 400+ gallons of water per day so we knew we had a leak, and it was just repaired (we'll see). This dragged the CYA and salt levels way down.
- I recently added 360 lbs of salt, and acid washed the IC40 to get the SWCG operating again now that the water has warmed up.
- Through the colder months, the pool guy had been using a chlorine floater and before starting up the IC40 I measured FC at 8ppm.
- With the IC40 behavior being totally unknown to me, I pulled the floater out and set the IC40 at 50%, thinking this would be low enough to have FC drop a bit. Obviously not.
- Today I added 16oz of 20 baume muriatic acid, to drop the pH. Will retest tomorrow.

So where should I go from here? Based on my TFP reading, it seems like I need to increase CH (400ppm?), increase CYA (70ppm?), and shut off the IC40 until the FC drops to ~5ppm then find the right setting to keep it there. Am I missing anything important?

One thing that's confusing me is that if I plug all of those goal values into the pool math calculator, I end up with a CSI value lower than -0.30. I believe the target is to maintain anywhere between -0.6 and +0.6 but have seen many say to target between -0.3 and 0. Playing with the numbers makes it seem that pH has the largest impact on CSI, and I need to have pH at 7.8 or higher in order to end up with a CSI between -0.3 and 0, while still keep my other chemicals near the recommended values. If I do the math with a pH of 7.6, it seems like I need a super high amount of CH and CYA to swing the CSI value into the range of -0.3 to 0. Does everyone chasing a good CSI value just run higher pH values than the traditional mid-point of 7.5?

Thanks!

 

[Texas Splash]

You are correct that pH has the largest and most immediate impact on CSI. That said, we typically don't line for it to exceed 7.8, but since your CH was so low it wasn't the worst thing to happen and it compensated a bit. But you should increase the CH to at least 250 now that you (hopefully) have that leak fixed. Once you get the CH to 250, local water should increase it more throughout the year and you'll be able to keep the pH in the 7s again.

As for the CYA, you want that higher as well (70). We round-up/down CYA results, so we'll call your current CYA 30 for now. Before you increase it, make sure there is no algae. No cloudiness or ANY indications of algae. If not, then increase the CYA to 70 and keep the SWG (FC) balanced as noted on the FC/CYA Levels. If you do see algae, then start a SLAM Process right away.

Other than that, I think you're all set.

 

[setsailsoon]

Jimmy,

Congrats on moving to TFP and starting to test! I did the same thing as you are about 6 years ago. Found this easy-peasy, dirt cheap, and got help along the way any time I needed it! Only thing I have to add is on the CSI. You'll find temperature has a large impact. But your first priority is to stay inside TFP ranges. Within that, try to keep the CSI in the narrower range is good for your salt system as it can minimize deposits inside the salt cell. This is a secondary target not the primary. First and most important is always to stay withing TFP ranges. I find it's not hard to do both unless the pool temp gets low like you have. As soon as it warms up I think you'll find it's easy to get into the CSI range as well. As Pat suggests operating higher in the pH range also helps.

Good luck with your TFP transition!

Chris