Does anybody just use a portable grey tank instead of having one physically mounted in/under their trailer? Looking for pros and cons to this set up as an option. I'm thinking of going this route to avoid mounting a tank under my trailer as the capacity seems limited to what will fit between the floor frames. I'd also like to save some room on the inside of the trailer to prioritize my fresh water tank supply which will be inside instead.

I am looking for ideas on specific paint/protectant to put on the undercarriage of my trailer to protect the wood from road spray, weather. Anyone have a good experience with a specific type/brand?

I am considering my options for both fresh and grey water capacity for my build. I will not have a black tank. I plan on having the fresh water tank in the interior of the trailer and would like to fit my grey water tank under the trailer. It seems options are somewhat limited for tanks that would fit between the floor framing (16 inches). I have considered possibly sistering two separate grey tanks together to expand capacity. Looking for others ideas/experiences as well as recommended capacity.