[andy east sussex]

when you see the small reverse osmos systems they have 2 carbon filters why does it take the strain off the membrane and would it work the same for the ro 4040 system by having 2 carbon filters

2nd

I know you should go with what works which is that speed liner paint on van but has anyone else used anything else effective at a fraction of the cost of the speed liner ?

[easy clean]

Put 6mm ply on the floor then all around the edge screw 2 x 1 batton. Then paint with protecta cote paint. Then put everything inside this new waterproof tray you've just built. If you do get a leak then just use a sponge to soak it up, this way the water is contained instead of running al round the van floor

[richard jagger]

I used concrete paint in a light grey. But since put a  coin ring, rubber floor in which I got in Bermeham when I went ti window cleaning show this year.Its very good product.Cost me 20 quid and I still had enough for he sides of the tank.

[SPE]

when you see the small reverse osmos systems they have 2 carbon filters why does it take the strain off the membrane and would it work the same for the ro 4040 system by having 2 carbon filters

2nd

I know you should go with what works which is that speed liner paint on van but has anyone else used anything else effective at a fraction of the cost of the speed liner ?

Hi andy, are you sure you don't mean a pre sediment and a carbon filter ? I don't think I have ever seen an ro with two carbon filters.
I have a 4040 with two 10" filters - a pre sediment and a carbon block.

In answer to your second question (and this is only in my experience)
Don't bother or concern yourself with speedliner or protectakote or anything similar.
If you have a ply lined floor remove it. Invest in good hose and leak free fittings, go to a diy store and buy some sort of under bed storage box or similar to use as a drip tray for brushes and pole hose, reel etc. and leave it at that.
I used protectakote in my peugeot expert and it now looks grubby, scratched, peeling. I think it detracts from the value of the van if I came to sell it, not to mention the time and expense it will cost prepping and applying it when it isn't really necessary. If the condition of your van floor is already in a good state then leave as is, any spillages of water will be visible and easily mopped up, ply lining will only hide this.
Regards
Simon

[Elfyn]

Carbon filters are used to remove chlorine from the water. Chlorine is bad for ROs.