[Pj]

What is best and why?

[mark dew]

I used to drive an escort 55 with a 250 litre upright tank and it was like being the captain of a ship in a squall, when it was full. It was slow and the drive experience was like the van was top heavy.
I now have a 400l tank in the back of a 1.9 dispatch and my van feels alot more stable.
As for best i don't know.
I would consider getting an upright tank in the future to create more space, but i think i would probably end up playing safe and get a lay flat tank because the drive feels steadier than when i had the upright.
If i had a bigger van i could be swayed by positive experiences of people driving similar vans with and upright tank.

[mci services]

i bought a 250l flat tank and it takes up all the floor space, i bought it thinking it would be more secure lower so more stable etc but i would like the space back so not sure.
not much help in my answer i suppose sorry

[Moderator David@stives]

flat.

Safer and lower centre of gravity

[steve m]

spot on, lower centre of gravity and make sure its centred in the van and against the bulkhead

[jewelcleaning]

what weight/litres could you go up to if you had to have it right up to the back doors of van?

[AJ]

flat tanks, boarded on top still gives room for everything, you just have to lift a little higher off the ground to get your stuff in.

[dd]

One problem with flat tank is when it gets low you may have to park one side of van on kerb so the water can still pump.

I have 600 litre upright tank in Dispatch, bolted to chassis. Feels safe to me but my wife tells me I drive like a slug.

[*Mr Tumble]

Both - flat and upright, aka 'square'.

[NWH]

i bought a 250l flat tank and it takes up all the floor space, i bought it thinking it would be more secure lower so more stable etc but i would like the space back so not sure.
not much help in my answer i suppose sorry

Put a sheet of ply over it and you`ve got your floor back.