RO/DI Bulid
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Sucks even worse if the image doesn't show up 
The Filter Guys also have a page on dual RO setups. They call it the "Water Saver". You basically take the waste water from one RO membrane and feed it into the second RO membrane. Then you T them back together through the DI resin. I sent them an email a while back and asked if they had any pressure issues T'ing it back together before the DI. They said they hadn't had any issues with the units.
In theory, it will make the second membrane wear out faster. The water going into the second membrane will have a higher TDS than the water has going into the first membrane so it will wear out sooner. How much sooner depends on TDS readings.
It also requires enough pressure. You have to have enough incoming pressure to be able to feed both RO membranes or a booster pump. If your house pressure is low to start with, or borderline, then after the first membrane you won't have enough pressure to feed it through the second membrane.
You do know that you can turn that unit into a 75gpd unit for about 50 dollars and not have to worry with it, right? Simply replace the RO membrane with a 75gpd membrane and replace the Flow Restrictor with a 75gpd Flow Restrictor. Same thing if you wanted to bump it up to use a 150 gpd membrane. Replace the membrane and the Flow Restrictor. That may be a better option if you are simply trying to get more water production without buying an entire unit.
The Filter Guys also have a page on dual RO setups. They call it the "Water Saver". You basically take the waste water from one RO membrane and feed it into the second RO membrane. Then you T them back together through the DI resin. I sent them an email a while back and asked if they had any pressure issues T'ing it back together before the DI. They said they hadn't had any issues with the units.
In theory, it will make the second membrane wear out faster. The water going into the second membrane will have a higher TDS than the water has going into the first membrane so it will wear out sooner. How much sooner depends on TDS readings.
It also requires enough pressure. You have to have enough incoming pressure to be able to feed both RO membranes or a booster pump. If your house pressure is low to start with, or borderline, then after the first membrane you won't have enough pressure to feed it through the second membrane.
You do know that you can turn that unit into a 75gpd unit for about 50 dollars and not have to worry with it, right? Simply replace the RO membrane with a 75gpd membrane and replace the Flow Restrictor with a 75gpd Flow Restrictor. Same thing if you wanted to bump it up to use a 150 gpd membrane. Replace the membrane and the Flow Restrictor. That may be a better option if you are simply trying to get more water production without buying an entire unit.
One Dumm Hikk;346111 wrote: Sucks even worse if the image doesn't show up
In theory, it will make the second membrane wear out faster. The water going into the second membrane will have a higher TDS than the water has going into the first membrane so it will wear out sooner. How much sooner depends on TDS readings.
Actually after thinking about it the waste water will actually have less going into the second membrane because ...some of the TDS is going into the first will be going out the "pure water" side (actually 4 TDS in my case) ....right?
It also requires enough pressure. You have to have enough incoming pressure to be able to feed both RO membranes or a booster pump. If your house pressure is low to start with, or borderline, then after the first membrane you won't have enough pressure to feed it through the second membrane. Water company said the pressure in my area was 85 +/-5
You do know that you can turn that unit into a 75gpd unit for about 50 dollars and not have to worry with it, right? Simply replace the RO membrane with a 75gpd membrane and replace the Flow Restrictor with a 75gpd Flow Restrictor. Same thing if you wanted to bump it up to use a 150 gpd membrane. Replace the membrane and the Flow Restrictor. That may be a better option if you are simply trying to get more water production without buying an entire unit.
Yes i know that but what fun would that be ...lol ....actually for my 55g and 29g the 50gpd (combined) is sufficient for my needs but i will upgrade when i need to replace the membranes
Where do i put the IFCE filter?
tap tds -128ppm
after pre filters -121ppm
pure after membranes -4ppm
waste -121 ppm
di -0ppm
i know that doesn't quite add up but my TDS meter has a 3% margin of error
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Let's assume you have 1 million parts water. Since you have a TDS reading of 128, that means 128 of those 1 million aren't water. A lot of the solids are trapped in the RO membrane but not all of them. If you filter that 1 million parts of water then you would, in theory, get 4 parts waste, 1 part pure water. That means you end up with 800,000 parts waste. Now, when the water goes through the RO membrane, it leaves the TDS behind and simply lets water through (simplified here). But, the TDS is on the same side of the membrane as the waste water is. Some of it is going to get dissolved into the outgoing water. It may not be but 10ppm but some will leave in the waste. That means you have 128ppm TDS in the waste water plus whatever got taken out with the waste so that you should have higher TDS readings in the drain water than the input water. The last thing I would expect to see would be lower TDS readings. If passing it through the RO housing and out the waste vent drops the TDS, why not continuously cycle it through the unit until it gets to 0 TDS with no waste water?
85 psi is good pressure and enough to run dual RO membranes. If you aren't sure what micron the ICFE filter is, I would call Kent and ask them. Tell them how many housings you have and what filters you have and you are trying to find out what order to run them in.
After you get all the sediment filters in the right order, you would have all your sediment filters, then an RO membrane, then a DI chamber. Take the RO membrane from the second unit and connect the waste water from the drain to the intake of the second membrane housing. Then run the good water from the second membrane into a T right before the DI. Then you have a waste line.
Going to call you in a minute or two.
85 psi is good pressure and enough to run dual RO membranes. If you aren't sure what micron the ICFE filter is, I would call Kent and ask them. Tell them how many housings you have and what filters you have and you are trying to find out what order to run them in.
After you get all the sediment filters in the right order, you would have all your sediment filters, then an RO membrane, then a DI chamber. Take the RO membrane from the second unit and connect the waste water from the drain to the intake of the second membrane housing. Then run the good water from the second membrane into a T right before the DI. Then you have a waste line.
Going to call you in a minute or two.
I was wondering myself if this would be possible ...if i monitor this and continue to get lower waster water readings do you think i could run it in a continuous loop?
I imagine my readings were just fluke because the people that make these probably would have done it already
....anyhow thanks for all your help Randy!
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