I have bought a pair of Rubbermaid 50 Gallon Brute Roll Out Containers for water storage for my new 180 gallon aquarium. Are they safe to use for storing my RO/DI water? Since last year I have been using the grey 32 gallon Brute for my 90 gallon with no problems. I just want make sure because they cost alot and don't want to contaminate my water.