any way i thought that 40 40s produced more waste than ro-man type systems isnt that why they can make larger amounts of pure in a shorter time?
You are chucking about 60 to 75% down the drain on a 4040. Sure you can tune it down to 50/50, but the membranes don't last as long, and up to and over £200 a pop for some of them, they are a bit too expensive for that.
That roughly translates to :
400l produced, is 600l waste.
250l produced, is 750l waste.
200GPD might be too slow, but a 300GPD shouldn't do too bad if you leave it on 24/7. All depends on how much water you use. If you use around 500l per day, it should be okay if your static.
I've got everything in the van, so I need quick fill times. 4040 for me.