is there such a thing as liquid dry acid?

[aggiejet]

Regarding the Ph section of PoolMath:

One of the solutions to lowering Ph is to add dry acid. My understanding is that dry acid is granular form of a chemical solid. The options are to "add xxx by weight or xxx by volume of dry acid."

I have interpreted the guidance given here and in other sections to mean that references to weight is for solids and volume is for liquids.

Is there such thing as liquid dry acid?

 

[Donldson]

Dry acid is sodium bisulfate. If you measure it out in a measuring cup then that is volume. If you pour it on to a scale then that is weight. Has nothing to do with whether something is solid or liquid.

 

[JoyfulNoise]

No, there isn't.

For dry products, the weight, as calculated, will be exact. The volume, as calculated, will be based on what is known to be the dry products density. For powders, the true density and reported product densities will be different since particle size and air entrainment matters.

You should always weigh dry products when you can as that is the more exact method. For liquids, one has to make a lot of assumptions that the container you actually hold in your hands has the exact concentration that is specified in PoolMath, so there can be very slight variations in effect if your muriatic acid happens to be 31% instead of 31.45% or your bleach is more like 9.5% instead of 10%. However, the differences are often trivial and so volumes calulated for liquid products can be considered exact-enough.