Trying to understand RODI

Ippyroy · Jan 25, 2020

Hi,
My tap water has a TDS of 15 and is 50 degrees and my PSI is 59. I have a BRS 100 gallons per day unit. It is my understanding that the cold temperature would slow it down. I also thought it would only process a hundred gallons a day. I started to fill a 44 gallon Brute can and after coming home 13 hours later it was an inch from the top. Does it actually produce a 100 gallons a day of pure water?

Greg P · Jan 25, 2020

My Vertex 100gpd unit is purported to produce 100gpd, but never did until I replaced the factory inline flow restrictor with a proper flow restrictor, and a proper flush valve/bypass unit.
Once that was done, I measured nearly a 1:1 ratio with 65psi.
I know, it's unheard of, but I measured it in buckets and the numbers were good.

I don't know the temp of my tapwater, but I keep my roll-out RO unit away from the floor register when running. In the current cold weather with the tap water being 'very' cold, my lines sweat, and my unit is in a bathroom, not outside or downstairs.

My Source water comes in @ between 6 and 12 TDS, based on our mountain-sourced water and the turbidity in the reservoir, and I get a consistent 0 T

As for 100gpd, I think I get closer to 50/60gpd.

And about cold water through your RO, apparently the colder water being denser is better filtered by your unit, so cold is a good thing, not a bad thing.

Greg P · Jan 25, 2020

My unit can be subjected to furnace heat if I'm not careful.
Works great as long as I tuck it away while in use.

Reef. · Jan 25, 2020

Ippyroy said:
Hi,
My tap water has a TDS of 15 and is 50 degrees and my PSI is 59. I have a BRS 100 gallons per day unit. It is my understanding that the cold temperature would slow it down. I also thought it would only process a hundred gallons a day. I started to fill a 44 gallon Brute can and after coming home 13 hours later it was an inch from the top. Does it actually produce a 100 gallons a day of pure water?

That’s an estimate, if the temp of the source water is on the high side it’s more efficient, also your water pressure is what most systems recommend so that will also give you max results.

The pressure of the water has the biggest effect on how much is produced, the temp not so much.

If the pressure is strong enough to force the water through the membrane at speed, then the temp of the water will hardly make much of a difference.

Ippyroy · Jan 25, 2020

So the 100 gpd rating is actually closer to the amount of good water, and not the total of good and waste?

Reef. · Jan 25, 2020

Ippyroy said:
So the 100 gpd rating is actually closer to the amount of good water, and not the total of good and waste?

Yes, and also the better the pressure the less waste water you will have, as the pressure is what makes the membrane more effective.

BamboozleBean · Jan 25, 2020

Yeah it varies, temp, water pressure, and the unit you’re using.
I have the Aquatic Life RO Buddie and it takes a good four and a half hours to fill a 5 gallon bucket.

Ippyroy · Jan 25, 2020

gregzz4 said:
My unit can be subjected to furnace heat if I'm not careful.
Works great as long as I tuck it away while in use.

You don't run DI resin? I was wondering about that. We also don't have any form of chlorine so I was wondering if I could swap out my filters with something else cheaper.

Greg P · Jan 25, 2020

I do not use DI. My RO filter is enough to remove my very low TDS.
My municipality uses Chlorine, not Chlorides, so I am able to get away with a basic 1 Micron Carbon cartridge.
I go through about 3500 gallons every 3 months, so I change my carbon every 6 months, and my pre-filter every 3 months.

Greg P · Jan 26, 2020

I'd recommend you still use a decent carbon filter, regardless of what you think is in your water.
Carbon filters remove many things we as novice chemists aren't aware of.

I posted wrongly above ...

My pre-filter is 1 Micron
My carbon is 5 micron, not 1 micron

Frey · Jan 26, 2020

I would be happy with almost 80 gallons a day with 50 degree water on a 100 gallon a day ro unit. May want to invest in a float switch to install on your trash can. I have forgotten more than once i was making water and went away only to come home to a nice puddle.

Ippyroy · Jan 26, 2020

Frey said:
I would be happy with almost 80 gallons a day with 50 degree water on a 100 gallon a day ro unit. May want to invest in a float switch to install on your trash can. I have forgotten more than once i was making water and went away only to come home to a nice puddle.

I came to work for 8 hours. My coworker called out so I had to work 12 hours. Forgot about water running. Ran home and only an inch to go before a huge mess. Will definitely be using a float valve in the future. I am very happy with the output. I just thought that I was only going to get closer to a third of that each day. No need for the water saver set up for now.

Frey · Jan 26, 2020

I only got about a 1/3 of that on my brs 100gpd unit on well water with only 40 psi water temp similar to yours. I added a booster, put a 150 gpd membrane in then added the 100gpd water saver boosting around 88psi. Can fill brute cans in less than an hour and i am saving water. Tds incoming from well 8-15 tds. Tds going into di resin now usually 1-4tds so i can't complain. Not consuming any cation resin but still going through a cartridge of anion about every 1000 gallons or a little more

Ippyroy · Jan 26, 2020

Frey said:
I only got about a 1/3 of that on my brs 100gpd unit on well water with only 40 psi water temp similar to yours. I added a booster, put a 150 gpd membrane in then added the 100gpd water saver boosting around 88psi. Can fill brute cans in less than an hour and i am saving water. Tds incoming from well 8-15 tds. Tds going into di resin now usually 1-4tds so i can't complain. Not consuming any cation resin but still going through a cartridge of anion about every 1000 gallons or a little more

Wow. Much better than I thought possible.

Frey · Jan 26, 2020

Yes but it cost a few bucks for all of that. I figure its the lifeblood of the system so make sure i have the best water possible and ability to make it on demand pretty much in case of emergency.

Also glad you stuck with it i think i seen a post around x mas time when you were really frustrated with some deliveries and other things with your more remote location

Ippyroy · Jan 26, 2020

Yeah. I had to take a step back and breath. Also a reef store just opened in Bozeman which is only 90 miles away. As soon as I found out about them I became stoked. Much safer with a LFS 90 miles away instead of 5 hours.