Grey/Black water tank capacity thinking

[Dick tracy]

what is the idea behind the factory's thinking when the grey tank is smaller and the black is way bigger on 25/27' than on the 23'? seems backwards.

[RivetED]

I'm not sure that 3 gal. is way bigger (we have the FC25-RBT 31-blk, 34-grey ~9%). Besides my black tank is always 'pre-charged' with about 3 gals to prevent pyramids.

When we boondock or have days between pump-outs we will use plastic bowls in the bath and kit sinks. If need be, they get dumped into the black tank.

It's good to have a lot of water in the black tank.

It may also have to do with load distribution &/or plumbing for any given floor-plan.

[PB_NB]

I like the idea of dumping grey water from the sink or shower into the black tank. That will help them fill up more evenly as well as stopping the pyramid affect!

[Dick tracy]

a 23FB has a 17g black and 37g grey tank while the 27fbt has 40 and 35g respectively. that is almost 2.4 times larger grey and a decrease in black versus the 23fb.

[Guy Looking]

Does anyone have any experience with replacing the tiny 18 gallon factory black tank on the 23 FB with a larger tank? Hoping to get up to 30 gallons or more so we can boondock for more than just 4-5 days at a time.