Some general advice I would give....
For storing liquids, I'd recommend a metal shelving unit with solid metal shelves, not the grating type. This is because if any of the containers develops a leak, the mess is much easier to clean up than if you had a wood shelf and now the liquid has permanently soaked into the wood. I just had an unopened gallon of engine coolant empty itself from the bottom, making a real sticky mess.
For shelves, I've either built my own from unastrut and plywood to get the size and strength I wanted. For me the shelves at the big box stores is either way overpriced or way too wimpy.
They have price tags plastered all over the shelving that I would like to buy, but I think the prices are for the items on the pallet racks, not the pallet racks themselves!
Brian