# RO unit upgrade: advice needed



## Natalia (Sep 15, 2008)

I would like to upgrade my RO unit so that I can produce more RO water and reduce the amount of waste water.

I currently have RO unit from Petsolution with sediment filter, carbon filter and 100gpd membrane as shown here: http://www.petsolutions.com/Petsolutions-Premium-RO-Units+I12517683+C44.aspx. I am running it off the faucet and I am geting 2g/hour =48gpd, much below the nominal membrane capacity of 100gpd.

I am wondering if installing in-line RO pump would help reduce product generation time. What pump would be appropriate?

I would also like to reduce the amount of wast water produced. I do not have exact number at hand, but my feeling is that for each gallon of product there are several gallons of waste. Any ideas how to improve the efficiency of the system?

Advice would be very helpful as these toys are somewhat expen$$$$ive (only the the pump would be $300).


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## addicted2reefin (Oct 2, 2009)

the booster pump would be able to help u with pressure, which may be a reason that you are only getting 1/2 of membrane capacity. Check out spectra pure. They have new ROs out that produce 2 GOOD gallons and 1 BAD gallon. THAT AMAZING. I own a spectrapure unit, not the new one tho . its a 90 gallon MPDI and i get about 120 gallons per day. 
also u may one to readjust ur flow restrictor. You may be wasting unnessessary water due to a improper lengthed flow restrictor. check w/ the manufacturer on the flow restrictor tho. 

spectrapure or ge merlin are te two most effiecent rodis i know of. 
the only way to rduce waste is to get a new system, or if ur flow restrictor is improperly adjusted. a booster pump would help with generation rate. there is a formula for production rate. the production rate is based on 60 PSI input water pressure and a water temp of 77 degrees farenheit.


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## Squint (Aug 13, 2009)

If you want increased output just get more and/or higher capacity membranes. What's your water pressure? If it's low, try connecting it to a washing machine hookup. I don't know if moving from a faucet connector to an inline below the sink feed would increase pressure.

Output is basically water pressure x membrane area x membrane permeability

You might be able to get more for your money buying piggyback membranes than a booster pump though. I don't know the prices offhand though.

The newer "high efficiency" RO filters just trade electricity for water. In other words, it's a shell game. There's no free lunch. You're creating an ion gradient and that will always require energy whether it comes from the booster pump or the potential energy in the town's water tower. It would be better in areas where you have plenty of money (to buy the booster pumps) and electricity but not water.

The average American uses ~140 gal of water per day so anything you use in the hobby really isn't that much. Water isn't "wasted" since matter cannot be destroyed, just the resources to purify it. The drain goes back to a treatment plant and since it's clean water, it actually dilutes the waste stream overall and lowers the treatment plant's burden, in a sense recouping the initial work done to purify water to potable standards.


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## addicted2reefin (Oct 2, 2009)

if ur water pressure is bellow 40 psi u will need a booster pump or a new hookup


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## Diana K (Dec 20, 2007)

If the incoming water is of poor quality then a better pre-filter may remove a lot more minerals, leaving less work for the RO membrane itself to do.

Ditto the other responses. Look into the specifications for the unit you have and see if there are optimum operating conditions such as temperature and incoming pressure. 

Divert the waste line form the RO unit to the garden to irrigate the plants. 

Set up a float switch in a barrel so that you do not have to monitor the filling. Set it up and it will automatically shut off when the barrel is full. (sort of like a giant holding tank)


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## Squint (Aug 13, 2009)

I forgot to mention that I use the brine to fill my washer. I change 40 gal per week which generates enough brine to fill my washer 4 times. That's equal to two loads of laundry which is about what I wash per week.


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