The 3 cups are what is recommended for the big one Dottie.. the XL. IMO it's too much as not all of it spreads around the bag. If memory serves me correctly, 1 cup is for the regular sized unit. Whereas I love the job they do polishing the water, they're too much of a PITA for me
Maybe because I break mine down after each use and let dry... don't like the idea of a stray "something" sitting in the water too long, and kind of reminds me of taking a bath in the same bath water over and over again... ewwwww
LOL
Can we say "cross contamination"
if used on more than one tank with the same charge
I have an XL that I think I've used 3 times... no matter how long I prime it I still get a thin layer of powder on the bottom of the BB tanks
I've used it mostly to clean up after meds, so I add a couple tablespoons of the Vortex powdered carbon and it does an amazing job.
For daily polishing I use the Magnum with the micron filter.... not quite as good, but soooooo much easier to clean and swap the cartridges
Jim