I am looking to purchase a complete WFP system but only have a van big enough for a 400 litre tank. Do I
1. Have an RO system in my garage feeding say a 1000litre holding tank which then supplys my 400 litre tank in the van and a di unit or
2. Do I go for an on demand RO system which allows me to top up as and when I need it. Been told that the On demand RO will not always supply my pole with water quick enough, is that true
You can have a holding tank in your garage with an ROystem on it. This will filter water around the clock (until the tank is full). In this tank you can have a submersible pump and say, a 1.5" transfer hose that will transfer water quickly to your van mount. The van mount will probably need a DI unit attached to do the final filtering as you use the water.
OR you can have an RO unit in the van which will filter the water as it fills the van tank - then through the DI unit as you use it. The drawback of the second method is that it can tie your van up for longish periods as RO filtering can be quite slow. So slow in fact that an RO unit will not be able to supply the water on demand. Maybe a huge industrial RO could manage it but I'm referring to just the realistic and practical options.
There are other configurations too. I believe that you can have a holding tank with RO on the way in and DI on the way out so that you fill your van with pure, ready to use water. This method would give a slower fill as it would need to pass through DI whilst filling the van mount. It's doable but not the best option IMO.
The best option for me was a 1,000 litre holding tank with 300 gpd RO amd submersible pump for quick transfer to van. In the van I have an 800 litre tank with DI. The water passes through DI as I use it. A DI will produce on demand but RO is too slow to do that.
