Take a look at your grey and black tanks. They should have VB22548H cast into the bottom surface. If so they are 33 gallons each and not the 28 gallons as listed in the Rockwood brochure or website.
There should be a sticker on the fresh tank and it should be VB28546W.
That's a 39 gallon tank. They show the freshwater capacity as 43 which does not add up. It should be 45 however the 6 in the heater is not usable.
Even the yellow weight sticker is wrong which probably tells you that a full load of water weighs 249 lbs. It should read 375 lbs.
Link to the tank manufacturers info.
Detail - Alpha Systems, LLC