SeaPerch and Baffle ball - Other products by WIFFLE 3.75" diameter 225 pcs

Other Products by WIFFLE- These are balls for use as baffles in fuel and fluid tanks. They are also used as one of the target balls in the SeaPerch competition.

This is the 3.75" diameter size packed in a master carton of 225 pcs. and priced with an additional discount. It takes approximately 90 of these balls to fill a perfectly sized 20 gallon cube. It will take quite a few less, however, depending on the interior dimensions of your tank. For example, if your interior tank height is less than 7.5" only one course of balls will fit in the space.
Since they float, you might also want to use less so that they don't crowd the fill pipe.
  Email - Hank@CTStore.com

  Yes, we are working on the displacement question though it should not be very much since the wall thickness is only about .075"