muratic acid ratio for DE cleaning?

[mathey]

I just bought a gallon of muratic acid to clean the fingers on my DE filter...but am confused as to the mix ratios

the manufacturer (Hayward) says a 1:1 ratio of 20% muratic acid

the acid itself says it is just under 40% Hydrochloric acid

any insight?

i read last night a guy used a 5 gallon bucket and added the gal of acid and 4 gals of water...this would be the 20% mix rate, correct?

 

[JasonLion]

First, always add acid to water, never add water to acid!!! It is also a good idea to wear eye protection and gloves and avoid breathing the fumes.

Diluting 20% 1 to 1 gives you 10%. If you are starting with 40% then you dilute 3 to 1 to get to 10%. Four times as much volume when you are done (3 of water and 1 of acid is 4 parts total) gives you 1/4 the strength. If your acid is actually 37.5%, which is one of the common strengths, then you actually want 2 3/4 of water to 1 of acid to get to 10%.