I measured the tanks.
Fresh: 62.8 gallons. Advertised: 63 gallons
Black/grey 32.1* gallons. Advertised: 34 gallons. Manufacturer: 30
The black and grey calculations are prone to more error due to the odd shape. Those tanks are suspended by upper edges or horns that run the length and may be part of the usable volume. These tanks are also tapered. *I calculated the horns would hold 2.1 gallons if hollow if not then the tank is the 30 gallons as stated by Ameri-Kart. Which is probably the case since they made the tank.
So the first replies may be correct in that there is something inside consuming space. Back to the rinse. I also have a borescope and have used it for a household sewer pipe inspection.
Reg
