cleaning and refilling, now some questions

[scott.MI]

I'me fimaliar with most of the information in pool school and whatnot, and I've gone through the "HOw do I use chlorine in my spa"

I'm refilling my inlaws hottub for them and getting them off the regualr use of dichlor to the dichlor then bleach method. They had some messed up readings so draining it and starting over trying to make print out for new fill and for normal maintinance.

now in one part of it, it says to start with TA of 80 and fine tune depending on how the PH handles it. Then later it says you can figure the optimum TA based on using the pool calculator >>>>

SO, what's a good TA then? That depends on your CH. If your CH is around 150 ppm, your TA would need to be 80 ppm for your water to be balanced with an ideal pH of 7.6. How did I come up with those numbers you ask? Easy, I went to http://www.thepoolcalculator.com website, and plugged in a Temp of 100, CH of 150, pH of 7.6 and adjusted TA until the CSI was close to zero. This website allows you to calculate your Saturation Index, based on the four Main parameters, Temp, CH, TA and pH. If CSI is less than zero your acidic, if it's greater than zero your alkaline and of it's close to zero your balanced.

What should I do start at 80 or use the pool calculate to figure out, based on temp,Ch, PH and find the CSI equal to zero? Saying CH of 140, PH of 7.4, pool calculate says TA 110 is optimum. (CSI of -0.1) and a TA of 80 with those same levels would be -.24. Is the difference from -.01 to -.24 not as big a difference as it sounds and anywhere from 80 to 110 is good?

 

[JasonLion]

Go with the TA level that lets you maintain PH at something reasonable. If TA is too high (and 80 is too high) the PH will go up extremely rapidly any time the jets are on. You shouldn't worry about CSI at all unless you have a plaster spa that does not share water with the pool.

 

[scott.MI]

Okay that just blew me for a loop, after reading the How do I use Chlorine in my Spa. Lets make sure I'm comprehending everything else right.

I'm getting a reading of 60 TA fresh from the house faucet...is that near normal reading for city water and if true, and 80 is too high, would it be good to just leave TA alone on a fresh fill at 60?

I'm also testing CH at what seems to be 110 also from house faucet is that a near normal for city water?

The lower your CH, the higher your TA and pH need to be to have balanced water. The higher your CH, the lower your TA and pH need to be.

Here's my recommendation. If your CH is much below 100 ppm, you should add calcium to bring it up to 130-150 range. If your CH is over 100, you can leave it alone and just make a note of what it is. The CH level will be used to determine your TA/pH levels.

If the article is correct, 110 CH seems to be on the lower side of the range but still acceptable and I would want hight TA and PH.
So would CH 110, TA 60, and Ph 7.4-7.6 be a good place to start for balanced water and see how the PH handles that level of TA and the airation of the jets?

Sorry just trying to cofirm some things make sure I'm not confused. This seems to have gotten alot harder from pool maintance aspect of it, now doing a hottub and dealing with CH and airation from jets.
Its a 350 Gallon fiberglass shell hot tub.

 

[scott.MI]

This is less of a question and more of a statement of ....wow.

According to what I read, 10PPM of Dichlor will raise CYA 9PPM. Using the pool calculator and figuring I will need about 25PPM of dichlor to reach my 20CYA level which equals 2 ounces of dichlor.

I'm looking at a 1oz scoop, Just 2 of these little things scoops is all it will take to reach 20CYA?! WOW

Now I understand how people end up with 100+ CYA

I chose 20 CYA based on the article,

He suggests a CYA of ~20 ppm. Personally I use a CYA of 30 ppm for reasons I won't get into here.

I chose 20 because the hottub is under a metal roofed gazebo and had a fence on 2 sides of it. Reasonable or should I go to 30?

 

[chem geek]

I'd go with 30 ppm. I initially said 20 ppm to be conservative after gathering a table of hot tub itch/rash/lung incidents on another forum where some of those appeared to be due to CYA buildup from Dichlor-only use, but problems really didn't show up until rather high CYA levels of at least 100 and more likely 200 ppm. Also, I found out later that CYA breaks down in a hot spa at a rate of around 5 ppm per month so a higher level is justified. 30 ppm is more reasonable and even 40 ppm is OK. I would not go any higher than 50 ppm and there is no need to do so.

Remember that the purpose of the CYA isn't so much to protect chlorine from sunlight because there won't be any in most spas with tight covers and that are often used at night. The reason for the CYA is to moderate chlorine's strength. If there were no CYA in the water, then the chlorine would be too strong and would oxidize swimsuits, skin and hair faster so would be more irritating and it would outgas faster so it would get used up more quickly and oxidize hot tub covers faster and possibly smell more (usually by forming chloramines in your nose). It would also produce disinfection by-products faster and for nitrogen trichloride, in greater quantity.

 

[TIMMAH]

.

So would CH 110, TA 60, and Ph 7.4-7.6 be a good place to start for balanced water and see how the PH handles that level of TA and the airation of the jets?

Sorry just trying to cofirm some things make sure I'm not confused. This seems to have gotten alot harder from pool maintance aspect of it, now doing a hottub and dealing with CH and airation from jets.
Its a 350 Gallon fiberglass shell hot tub.

yes

like said above the big thing is your ph. so you want your TA where you get a ph as close to 7.6 as you can. I find 60-65 is good for my spa but I also use bromine tabs that lower ph and ta over time.

main thing is keep your ph as close to 7.6 as you can.
ta 50+
ch 100+

I wish I had water like that from the tap, I wouldn't do anything to it my tap water is CH 225, TA 210, PH 8.4+
it takes me hours to get that TA down to 55-65 so I have a ph of 7.6
I don't even bother checking CH since mine is so high. but in your case I would at water changes just to make sure it's above 100. I just keep my TA above 55 and ph between 7.4-7.6 as best as I can.