Water Tank Noise Insulation

[Eizenjin91]

For those of you that have a water tank in your SUV (not pickup bed or under the vehicle) what do you use to eliminate or reduce that god awful sloshing noise when the tank isnt full? I have thought about dynamatting the tank then foam or wallboard insulation around it with a wooden box on top? I have tried putting some mini wiffle balls in the tank but that really didn't help anything. Thanks

 

[rayra]

maybe some polypropylene batting shoved in the tank, a la a waterbed mattress. Wouldn't take much volume but out to cut way down on the slapping. Not sure of its effect on potability though.