RO System selection

[BACbrewer]

The RO systems are rated at GPD but I’m more interested in (max) GPM. Anybody have any recommendations?

 

[Bobby_M]

Unless you have a need to make several hundred gallons, the practical system for a homebrewer is going to be 50-100 gallons per day with a holding tank of some sort. You can run a few 200 GPD membranes in parallel but you'd need a booster pump to get the inflow to about 100 PSI to make it efficient.

 

[day_trippr]

The RO systems are rated at GPD but I’m more interested in (max) GPM. Anybody have any recommendations?

The Israelis have some enormous desal plants using RO systems...

 

[BACbrewer]

Unless you have a need to make several hundred gallons, the practical system for a homebrewer is going to be 50-100 gallons per day with a holding tank of some sort. You can run a few 200 GPD membranes in parallel but you'd need a booster pump to get the inflow to about 100 PSI to make it efficient.

Thanks for the “order of magnitude” reality check! very helpful...

 

[MaxStout]

I just have mine mounted over the utility sink in my basement, and fill up a bunch of 5-gallon water jugs. It's 75GPD, so it takes less than 2 hours to fill a 5 gal container.

 

[NSMikeD]

Fwiw I have a cheap portable RODI four stage unit (for my reef tank) and 5 gallon plastic containers. I’m fortunate that my tap is soft enough for 99% of my brew needs but since I. brew 2.5 gallon batches I have the capability of making water for beer when I prefer a clean slate. In any case (and I am making 5gals right now for my fish tank auto top off) it takes about 1 hour to make 5 gallon as my 75GPD cheap unit of 0TDS ( I have a meter on the unit).

I brewed a NEiPA the other day and it was nice to grab one of the containers I had made a few days earlier

I use the spigot for my washing machine. When I’m done, the unit gets put away.

The TDS meter lets me know when it’s time to change the filter cartridges (about annually)


(To reiterate, this has a Dionizing (DI) filter, which brings my water down to 0TDS, slightly lower than plain reverse osmosis, which I take into consideration water calculators which might include some ions in their base RO profile).

 

[Buckeye_Hydro]

Unless you have a need to make several hundred gallons, the practical system for a homebrewer is going to be 50-100 gallons per day with a holding tank of some sort. You can run a few 200 GPD membranes in parallel but you'd need a booster pump to get the inflow to about 100 PSI to make it efficient.

You certainly don't want to run a "few 200 gpd membranes" with a typical residential-scale system (10" x 2.5" prefilters with 1/4" OD tubing and 1/4" fittings).

Russ

 

[AlexKay]

Get the biggest one your water pressure can support, which is likely 100 GPD. A system typically fills a reservoir; get the biggest one that can fit where you want to put it. Typically sizing those two things big doesn’t come with too much of a price premium, and the convenience is very nice.

You’ll pull from the reservoir quickly, but then you can calculate GPM by dividing GPD by 1440 (no surprise!) which ends up being slooooowwww.

(Thanks @Buckeye_Hydro … a year out my system is trouble free.)

 

[Buckeye_Hydro]

Filmtec membranes, arguably the best in the business, rated from 36 to 100 gpd are factory spec'ed at 50 psi. Nearly every single other brand of residential membranes are spec'ed at 65 psi. This is an important differentiator when you're shopping for a new membrane.

Our 150 and 200 gpd membranes are rated at 65 psi.
Our commercial membranes of higher capacity are spec'ed at 80 psi or higher.

Common residential-scale booster pumps work well with up to 150 gpd capacity. We have a larger booster pump for capacities up to 400 gpd. Booster Pumps | Pressure Booster Pump | Delivery Pump - Buckeye Hydro

Above that you are looking at a separate electric motor and a pump (as found on commercial RO systems).


Russ

 

[Broken Crow]

Just want to ask you guys if anyone can chime in here with what it cost to run, specifically; How many gallons before you have to replace filters and such?

 

[Buckeye_Hydro]

Your prefilters, meaning the filters that touch the water before it gets to the RO membrane, you'll typically replace every 6 to 9 months or so for about $15 to $25 depending on which/how many prefilters you have. You'll typically get 2 to 5 years out of an RO membrane. Replacement is $35 to $55 or even more, depending upon which membrane you're using.

We worked with a commercial customer that was only getting 2 weeks out of a $250 membrane - we got that system squared away so that he'll now get a reasonable life span out of the membrane. We also have customers that are over the 10 yr mark on their membrane.

 

[Bobby_M]

You certainly don't want to run a "few 200 gpd membranes" with a typical residential-scale system (10" x 2.5" prefilters with 1/4" OD tubing and 1/4" fittings).

Russ

The question was about Max GPM. I prefaced it by saying you need that but if you really wanted to crank "max GPM" like the OP asked, paralleling multiple membranes with the pressure of a booster pump would certainly do it. I don't recommend it.