How much MA to drop the TA

[wjr75]

Hello All,
How much MA would be required over time to drop my TA from 80ppm to 50ppm in a 900 gallon hot tub? I want to add boric acid once the TA gets down to around 50ppm without having to test TA all the time prior.

Thanks
Will

 

[pooldv]

7 or 8 oz should do it.