anyone have a water pressure gauge for RO?

[Piazzon12]

SD... this is a new unit hooked up yesterday. I want to verify it works properly before I ever bother looking/caring about TDS. If this is the rate at which it will produce water (30 gallons/day) I'm better off buying.

Mach: it's in my basement near a wash basin. The pressure's not terrible, but not great as I'm at the top of the hill. I will try to get a pressure measurement tonight. I'm sure the temp is rather cold as it's in the basement and near the house input

 

[03Mach]

Even if you have low water pressure you can fix that buy putting a booster on the line. with a pressure booster you will be able to set the water pressure for what the unit call for.

How much waste water are you getting per gallon? I think with mine it's like 4 gallons for every 1.

 

[Piazzon12]

Feed pressure is only 35 PSI... looks like I need a booster pump

 

[RCBrooke]

I wasn't happy with the output volume if my RO/DI unit either but 50' of line in 80 degree water preheats the feed water enough to just about triple my output. I'd give more exact numbers but I don't remember the exact figures from last winter when I hooked it up. Course I didn't hit on preheating until after I bought an extra RO unit, flush kit and pressure gauge.

Randy

 

[03Mach]

What does the system say for optimal pressure?

 

[Piazzon12]

I dont think the system does, and I didnt read the RO membrane before putting it in, but from what I've read about other systems, it is a minimum PSI of 50 and 77C for best performance

 

[Buckeye Hydro]

Filmtec membranes are spec'ed at 77 degrees, 50 psi, and 250 ppm feedwater. Other brands are similar, except they are spec'ed at 60 or 65 psi.

50 to 65 PSI however won't give you the best performance however - the higher the better, up to about 90 PSI. I say 90 because typically there is at least one component in an RODI system (not the membrane!) that has a max operating pressure of 100 PSI.

For those w/o a pressure gauge - instead of spending your money on a hardware store gauge, think about adding a pressure gauge kit to your system. Not only can you tell what your home's pressure is, you can also use it to tell when your prefilters are clogging.

Russ

 

[Piazzon12]

ok, got booster pump, transformer, pressure switch, pressure gauge, inline TDS, 25 ft of tubing, a heater, and a bucket.... needless to say the RO is finally running...
Anyone using an Inline TDS??? and where did you put it? At the very input and output of the system?? The filterguys only show it around the DI, which doesnt make much sense to me, but I dont know anythign about RO DI. Right now I've got installed there and have 2ppm going in and 0 ppm coming out of the DI only

 

[Dave VG]

The way I understood it you want to see TDS after the RO and after the DI Adam. That checks both filtrations.

 

[03Mach]

It seems like it really shouldn't matter too much, as long as you are getting good production and low TDS. I personally just use a hand held and measure all over the place.

 

[Buckeye Hydro]

Use your TDS meter to measure, record, and track the TDS (expressed in parts per million) in three places:
1. Tap water
2. After the RO but before the DI
3. After the DI.

The TDS in your tap water will likely range from about 50 ppm to upwards of 1000 parts per million (ppm). Common readings are 100 to 400 ppm. So for sake of discussion, let's say your tap water reads 400 ppm. That means that for every million parts of water, you have 400 parts of dissolved solids. How do we go about getting that TDS reading down to somewhere near zero?

If you do some experimenting with your TDS meter, you'll note that your sediment filter and carbon block filter (collectively called prefilters) do very little to remove dissolved solids. So with your tap water at 400 ppm, you can measure the water at the “in” port on your RO housing and you'll see its still approximately 400 ppm.

The RO membrane is really the workhorse of the system. It removes most of the TDS, some membranes to a greater extent than others. For instance, 100 gpd Filmtec membranes have a rejection rate of 90% (i.e., they reject 90% of the dissolved solids in feed water). So the purified water coming from your 100 gpd membrane would be about 40 ppm (a 90% reduction). Filmtec 75 gpd (and below) membranes produce less purified water (aka “permeate”), but have a higher rejection rate (96 to 98%). The life span of a RO membrane is dependant upon how much water you run through it, and how dirty the water is. Membranes can function well for a year, two years, or more. To test the membrane, measure the total dissolved solids (TDS) in the water coming in to the membrane, and in the purified water (permeate) produced by the membrane. Compare that to the membrane’s advertised rejection rate, and to the same reading you recorded when the membrane was new.

After the RO membrane, water will flow to your DI housing. DI resin in good condition will reduce the 40 ppm water down to 0 or 1 ppm. When the DI output starts creeping up from 0 or 1 ppm to 3 ppm, 5 ppm, and higher, you know that your resin needs to be replaced. Sometimes people complain that their DI resin didn't last very long. Often the culprit is a malfunctioning RO membrane sending the DI resin “dirty” water. This will exhaust the resin quicker then would otherwise have been the case. Sometimes the problem is poor quality resin â€"œ remember that all resins are not created equal!

Russ

 

[Piazzon12]

Thanks for the info Russ!