The Cal hypo scoop - is it volume or mass?


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Bronze Supporter
May 22, 2011
Miami, FL
Pool Size
Salt Water Generator
SWG Type
CircuPool RJ-45
Good morning
This is a dumb question, but it shall get asked.
Buckets of cal hypo or any chlorine come with a blue scoop that's marked with grams and ounces.
My brain tells me that those markings are volume and not mass. Right?

I ask because the poolcalc gives you the option of adding chemicals by weight or volume, and those 2 numbers are different.


Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
Texas, San Antonio/Marion, South-Central Area
Pool Size
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
That question comes up from time to time. A basic rule of thumb is to use Weight for solids and Volume for liquids. In most pool care cases though, an error encountered by using volume measurements for solids or vise-versa won't make a monumental difference, with the exception of a very large dosage which might cause problems. For example, I use the same measuring cup whether I'm adding granular stabilizer or muriatic acid. Like grenades, we just need to be close. :)
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