Error in Pool calculator for TA?

[bwv772]

It says I need 1360 grams of soda ash to bring down TA 100 ppm in a 68000 liter pool??

This doesn't sound right, Taylor recommeds 53 pounds (24 kilos) if I remember.

Can someone confirm?

[Demons1964]

Lowering by 100ppm is a huge amount. What is your TA and pH at the moment and what type of pool do you have? Also, are you using test strips or a chemical drop test?

Irrespective, soda ash will RAISE the TA. To lower TA use sodium bisulfate or muriatic acid. To lower by 100ppm you would need to use 38 pounds of sodium bisulfate. I wouldn't be adding more than 4 pounds per day. Note that your pH will drop considerably as well, that's why I'm interested in your other readings because that is a massive amount to change.

[Guest]

Lowering by 100ppm is a huge amount. What is your TA and pH at the moment and what type of pool do you have? Also, are you using test strips or a chemical drop test?

Originally TA was at 320, pH was at 8.0+, calcium at 240. Pool was filled recently from a cistern because the customer is strickly on well water. Draining is not an option (filling it is $600). It's a 68000 liter fiberglass inground with heatpump. pH was brought down to 7.2, the water cleared up nicely, no more rings around the waterline but the TA remains high at 250. (Sorry I made a mistake in my initial post I of course meant sodium bisulfate).

All tests done with a Taylor K2005 with fresh reagents.

Because it's late in the swim season here in Canada I figured we'll keep the pH low to minimize effects of the high TA and we'll deal with it next year. Customer is very happy now about the water clarity, it has never been this nice. However she may decide to bring in the contractor to fix some lowsy paint work in the shallow end, this may include a draining and refilling paid for by the contractor, I don't know what's going on with that, but I told her we should test the water before dumping it in the pool next time.

I was just curious as to why the calculator here specifies 1.3kg. Taylor's tables recommends 17.5 kg (38 pounds) and their website recommends 58 pounds (!!)

Regards,