After adding Borax, water is drying out skin.

[waterbear]

DE in the water will not really have any impact on water chemistry but might have a slight drying effect on the skin since it is a dessicant. Good news is that it WILL filter out given time. How much DE did you put in your sand filter? We normally recommend starting with half a cup in a slurry: waiting about an hour or so to check the pressure and if you don't have a 1 psi rise in pressure add another half a cup slurry until you do. Most sand filters need between 1/2 cup to 2 cups of DE to get a 1 psi filter increase and the increase does not occur immediately. It usually takes a few hours as the filter "gets dirty" ( a dirty filter will filter better than a clean filter ) and the pressure to increase. Adding the DE just starts this process faster than it normally would by filling in between the sand grains and filtering out smaller particles. As you have found, if you dont wait long enough or add too much DE (2 psi from DE alone is too much DE) the filter pressure will rise very quickly and you will have to start all over again after backwashing with less DE.

[Willjay]

Probably a cup the first time, less the second, and even less, around half a cup, this last time. We'll see how it's running tonight.

[Willjay]

My water chemistry yesterday

chorine drop test indicates greater than 3 with a pH of 7.5;

The strips indicated, on two separate tests;
FC: 3-5
TC: 3-5

TA 120
CYA around close to the 50 ppm color

Checked my pump in the evening and it was running around 20#. Which is 5 over instead of 15 over, so we're making progress. Will redo, but my pool was as clear as I've ever seen it. My 11 year old son even noticed (and he isn't a "noticer"). I've seen it this clear before, but it's usually fleeting and unexplainable.

Also, my pH is holding steadier than normal. 7.5 two days after adding acid is, for me, uncharacteristic. It usually like to jump right back up above 7.6 within a day.

[waterbear]

Get yourself a better test kit (Taylor K-2006) and then use it to drop the TA to 70 ppm. You will find you have even better pH stability. Then use the Taylor kit to get the CYA to 80 ppm.
You just cannot do it with strips. They do not have the resolution and you inexpensive drop kit is not going to cut it either. I am going to guess it has a comparator for the chlorine test that has shades of yellow. Right?
If it does it only tests total chlorine, not free chloirne and combined chlorine, no matter what the instructions might say! OTO does not accurately measure FC.

[Willjay]

I'm planning on it Waterbear, I'm just going to have to wait a week or two to purchase it.

I have a question about your recommendation of CYA at 80. If in the evening I'm still running 3 - 5 ppm of chlorine after a 95 F day and pool water temps around 90 F with a pool in virtually no shade, do I really need to increase my stabilizer? Is it preferable, all things being equal, to run your chlorine at the lowest ppm that is still effective and sustainable?

[waterbear]

Not in a salt pool. Higher CYA directly translates into lower cell output/pump run time to maintain the same FC level which directly translates into less outgassing of CO2 from aeration created by hydrogen gas generation n the cell which directly translates into slower pH rise/better pH stability.

Lower cell output also translates into longer cell life.

[Willjay]

That's interesting, WB. Thanks for all the advice and help. You guys are great.

I checked my pH last night and it's still 7.5. Unprecedented for me to hold this pH this many days after adjusting.

The DE in the sand filter project has it running 2 1/2 to 3 pounds over normal. The water is gin clear, the best it's ever looked.

Oh, a following up on the thread title. I've had no noticeable issues with skin drying. It feels great to me. It will have to pass the big test over the weekend, my wife's opinion. She doesn't usually get in the pool during the week. I'll report back on her experience after the weekend.