Which model is right for you?

Rather than the expensive RO option, we encourage home owners to first look for non-RO type special purpose filters, described above, to accomplish specific filtration objectives. In addition to its costliness, RO process is rate limited and also has to throw out, on average, about half the incoming water as dirty waste. Because RO makes water slowly, you have to store the processed water in a storage tank big enough to meet the peak demand of a household. Then GPD rating of the unit has to be large enough to refill the tank before the next peak demand period arrives.

A whole house RO system consists of four functional blocks. 1) Pretreatment filters, 2) RO, 3) atmospheric storage tank plus repressurization pump, and 4) post treatment filters. Pretreatment and RO are explained below. Click for storage tanks and click for repressurization pumps. In a modern house where sinks, showers and baths are separately plumbed from toilets and such, a bladder type tank or two may substitute for a large open tank and a repressurization pump.

Some people describe the raw RO water as acrid, tangy or sharp tasting. In fact, depending on the supply water chemistry, the RO water can be acidic. The post treatment stage 4) can consist of an acid neutralizer, carbon "polishing" filter or two, sometimes followed by a UV filter. Neutralizer if permeate is excessivly acidic, carbon rounds off the taste, and UV for organisms that may potentially grow in the post-RO storage tank/pump, particularly in warmer climate.

Source Water Preparation - to prevent premature membrane fouling, to increase pure water to waste water ratio

Large RO membranes are expensive, hence, most source water is pretreated so as not to foul them up ahead of their natural life. The cleaner the water, the longer the membranes will last. We then can set the pure water recovery rate that much higher, thus saving on water bills.

Source water quality requirements

• Water temp: 85F max
• TDS: 2,000 ppm max
• Iron tolerance: 0.5 ppm max
• Hydrogen sulfide: must be removed
• Silica tolerance: less than 125 ppm, antiscalant should be considered for over 75 ppm
• Turbidity: must be removed
• Hardness: over 10 gpg should be softened
• pH range: 3-11

A source water analysis is recommended before considering a large GPD RO system. We can help you pretreat water for most conditions. The throughput capacity of the pretreatment equipment must be sufficient to adequately filter the sum total of the permeate flow (RO GPD rating) and the anticipated waste water flow into drain.

At lower source water temperatures of less than 77F (25C), actual RO production will be less than the system GPD rating. To estimate the actual production, GPD rating has to be divided by 1.19 at 68F (20C), by 1.47 at 59F (15C), by 1.89 at 50F (10C), by 2.58 at 41F (5C). The temperature derating effect must be included in your system design consideration.       Top  

---

Com II Model Reverse Osmosis 800, 450, 250 and 150 GPD

Back to models & prices How to order

What it does Sits in the basement (at point of entry) and treats the whole house water Works with chlorinated municipal water or well water Our best seller, work horse, most iterated design/parts selection for reliability Prefilters: Slimline (2-1/4" dia x 20" long) sediment and carbon TFC membrane at 200 psi, 95-99% salt rejection One year factory warranty Stainless membrane housing, powder-coated steel bracket High pressure brass fittings and nylon tubing Inlet/outlet pre-filter gauges, liquid filled system gauge Additional pressure gauge for sealed storage tank Adjustable waste/recycle flow controls, optimum water recovery Storage tank pressure switch, low pressure safety switch Feed water solenoid valve, 1/2 hp motor (3/4 hp for 800 GPD), rotary vane pump Straightforward installation, simple operation, see installation diagram compact design with highest quality US components, needs minimal space Source water test/analysis is recommended prior to unit purchase

Unit and operating cost

Unit price Com II-4 $2,202, Com II-3 $1,828, Com II-2 $1,598, Com II-1 $1,547

Unit price is for the RO unit, does not include external pretreatment, pure water storage tank or repressurization pump

Crating/shipping the RO unit from CA is extra, CA residents add state sales tax

Available options at added cost

Com I Model Reverse Osmosis 800, 450, 250 and 150 GPD

What it does Sits at point of entry (basement), treats the whole house water Works with chlorinated municipal water or well water Two Big Blue Short (10" long) carbons, one sediment prefilters TFC RO membrane operating at 200 psi, 95-99% salt rejection One year factory warranty Water storage tank and repressurization pump are not included Straightforward installation, simple operation, see installation diagram Compact design with highest quality US components Inlet/outlet pre-filter gauges, liquid filled system gauge Storage tank pressure switch, low pressure safety switch Feed water solenoid valve, 1/2 hp motor, rotary vane pump Fixed waste and recycle flow controls, optimum water recovery Source water test/analysis is recommended prior to unit purchase

Back to products & prices How to order