4 gph on 75 gph RODI unit

[syncro]

Is this reasonable?
- 4 gallons per hour on a Buckeye Field Supply 75 gph RO/DI unit
- 2 filter stages, RO membrain, DI stage
- 82 PSI on the pressure gauge on the unit
- I am in Calgary (Renfrew)

Thanks!

[intarsiabox]

Not familiar with the brand you have but the RO/DI units supplied by most marine stores are from 50-200 gallons per day not hour.

[Myka]

Is your pressure always that high? Are you using a booster pump? That is higher than typical tap water pressure which leads me to believe that your RO membrane is clogged up which means you either have to clean it or get a new RO membrane. Do you use a flush kit on it? Some people say flush kits help...I'm not sure, but for $15 I use it. I am researching cleaning RO membranes...I have read it can be done with citric acid which I already have, but I haven't tried cleaning it yet. Send an email to Buckeye, they have great customer service.

[davefrombc]

RO/DI units are rated in gallons per day. 4 gallons per hour would come out to 96 gallons per day; so that unit is either outperforming its rated output, or there is a problem with the membrane allowing raw water to bypass it . Efficiency of RO units depends a lot on pressure . Up to its rated maximum, the higher the inlet pressure , the more efficiently a unit will run and deliver a higher percentage of RO water compared to waste water .
Municipal system generally have sufficient pressure , but most rural well water systems require boost pumps for a RO unit to work properly .
82 psi is very high for a municipal system . I would guess either the gauge is faulty , or there is either a boost pump on the RO system .

[syncro]

gph vs gpd! Right, thanks.

No boost pump. Gauge has been reading 80 PSI since I installed the unit a few months ago. I only have a small nano reef so I haven't run much water through it. I do run it occasionally for a minute or two with the flush kit bypass open. I haven't measured it other than eyeballing with a 5g bucket so it possible it is outputting 3 gph / 72 gpd.

[mike31154]

My system input pressure is also around 80 psi, give or take. I adjusted the Pressure Reducing Valve (Watts 25AUB) in my plumbing to bump it up from the default/standard 50 psi. According to the spec sheet, the adjustment range is from 25 to 75 psi, so beats me how I'm getting 80 and on occasion even a tad over 90 psi. Maybe it's broken. City water pressure upstream of the PRV is generally around 110 to 120 psi. If you find you have one of these in your plumbing, it more than likely has a strainer which should be checked & cleaned periodically.

I've been thinking about installing a king size whole house sediment filter just upstream of my PRV. This would allow me to remove one of the sediment pre filters from my RODI system & perhaps up the performance.