Phosphoric Acid help with reducing alkalinity

[orlando]

Having been disappointed with CRs for reducing alkalinity and boiling being a bit of a PITA I have taken Gordon Strong's advice and purchased some phosphoric acid at 75% to use to reduce alkalinity. My HLT is able to hold all the liquour I need for a brew so would like to treat between 40-50 litres for a 25 litre brew length. Can anyone tell me what amount I would use to ensure that the alkalinity is kept under 6 for the whole process? I haven't been able to find this information on the web so any pointers would be welcome.

[vacant]

Surely you have to test your water with a salifert kit or similar. Then if your chemistry knowledge is bad or you don't trust the indicated strength of your acid, treat 10L with a small known amount of acid and test again. You'll then be able to calculate the amount/L needed to bring down your total water.

[Aleman]

Gordon Strongs technique is to use RO water for the sparge with phosphoric acid to take the pH down to below 6.0 . . . Nothing to do with reducing the alkalinity of the sparge liquor . . . Unless you are using RO water, then it's difficult to apply his technique

[crookedeyeboy]

Using Phosphoric Acid will do exactly the same thing as AMS (CRS) but in differing amounts. It will reduce the carbonate by releasing Hydrogen ions.

1.5ml in 25lts will approximately reduce the alkalinity by about 32ppm.

The danger with Phosphoric Acid IIRC is that it can form calcium phosphate once heated, therefore losing essential calcium needed in the mash etc