Let's back up some guys.
There are RODI units pre-plumbed to send RO water to two locations:
1. A pressurized storage tank that supplies a drinking water faucet, and
2. Also on to a DI stage.
It's not quite as easy as plumbing in a tee, a well configured system like this assures that RO water from the pressure tank never makes its way to the DI stage. The water from the tank also has to pass through a taste and odor filter.
Beware - there are a LOT of mis-configured systems on ebay that claim to provide drinking water and RODI water.
If a drinking water system requires proprietary filters, yes - you'll pay through the nose for those, and chances are they are not of equal quality to the filters in a well-made reef system.
How can a rodi unit make 90 gal a day when this whirlpool unit only makes 5 and that's when the filters are new?
The gallons per day produced by an RO system is determined by the RO membrane and the flow restrictor. Drinking water systems are often built with very slow membranes because the demand for water from these systems is minimal. That said, 5 GPD is VERY slow, even for a drinking water system. I wonder if the membrane in that system is scaled or fouled?
this kitchen unit flushes 24 /7
The system is malfunctioning and is costing you a lot of water. It's essentially like leaving a faucet on 24/7. I'd fix this pronto. It is also prematurely using up the limited capacity of your prefilters. Remember - all that water going down the drain is going through your sediment filter and carbon filter(s).
Will a unit making 90 gal a day flush that much more?
Any system that is configured correctly and working properly will make about 4 times as much waste water than purified water. That ratio goes us some if you are sending the purified water into a pressurized tank. A higher capacity system will make the pure water faster.
you'll need a Bypass valve to open a bit and raise the TDS of drinking water to around a 100 as it tastes better
This is probably not necessary. Drinking water RO systems using a pressurized tank have been making drinking water in thousands of homes for decades w/o blending the water.
We have a T right after the DI chamber with water going to the house and the Rodi barrel.
There is a much better way to plumb this system - you want RO water for drinking, rather than RODI water.
If you're at 40 psi or so, you shouldn't need a booster. They do improve efficiency, but not necessary unless you're looking for a ratio around 2:1.
RO systems (really, RO membranes) are significantly affected by water pressure, and water temperature. At lower pressures, water production slows, and the purity of the RO water is affected too. It's not as if a RO system "won't work" at lower pressure - the performance is just not as good. We find that customers are typically willing to put up with the reduced performance down to around 40 psi. Most people have more than 40 psi in their homes, and don't need a booster pump. We don't recommend customer get a pump specifically to control the ratio of waste water to purified water - that is better accomplished by a $4 part called a flow restrictor.
Russ
