Well I’m going to make for me what is a very large purchase and I just wanted to lay out everything and ask some other reefers for there opinions, make sure I didn’t miss anything. I hated when I got my first RO unit when I was told I should add a DI, then I should really add two DIs, I should add an inline TDS, then I should add a second membrane to get a higher clean water to waste water ratio, then I should really add a pressure gauge to tell when my pre-filters were shot. By the time I was done making up a wish list of things I needed to add it would have cost me more then the original unit did!
Well it is time again to change both my prefilters and my RO membrane and it is time to make a bigger change. I want to buy a unit that has just about everything I really need. The one I have is basic and I would rather not just add parts to it, but buy a complete unit.
So here is the list of things I am looking for.(hopefully I can get some feedback to add things to the list or cross things off)
75GPD(at least)
Two DI cartridges
Pressure Gauge
Float Valve
Drinking water T off (probably could add this on my own)
Membrane flush kit
I will probably also look into running dual membranes off the same prefilters in order to reduce the amount of water I am wasting.
I will probably also look into running dual membranes off the same prefilters in order to reduce the amount of water I am wasting.
????
Curiosity, We are talking Ro membranes not Di correct
Are you running the waste of the first into the 2nd membrane? How much will 2 membranes save on water vs. earlier replacement of the membrane? I thought the waste water was to wash the contaminates away as to not destroy the membrane as fast??
Just asking cause I am not 100% sure.
I don’t know anything about using two membranes, but I can tell you that having 2 DI’s has extended the life of the resins and allows me to use 0 TDS water at all times. I started out with 1 and added a second about 6months later. I got my RO through Melev and I have been very happy with it. I think using a booster pump if you have lower water pressure can help reduce the mount of waste water. I need to look into this myself.
couple of thoughts for you. using two membranes comes at a cost. you will not be able to have 0 TDS water. if you could i would imagine that two membranes would be pretty much standard. if your concern is environmental look into ways to utilize your gray water. if its financial, pm me and i will tell you how to get 0TDS water for $0! As far as PSI guages i dont think the are necessary. IF your PSI is up to par then its not likely to flucuate and monitoring it is almost pointless. Two ways to harness for drinking water. You can get a storage tank or you can run it through a refrigerator with a water dispenser. If using the refrigerator option you will more than likely have to purchase a pump. I forget what they are called, but they are pretty cheap. Also, before to T it off before the DI and run it through a carbon filter instead. I can show you how to build a membrane flush kit for $5. Dont know much about twin DI. I use the pre-build non-fillable ones and i only have to replace once a year. Let me know what you need the float valve for and i might be able to give you an idea. Also, usplastics sells the nicer float valve that typically goes for $12-$15 for $8.
Your right. I believe the optimum range is right around 60-70PSI. Personally i wouldnt go much higher than that range because a lof of the components of an RODI are rated for 75-100PSI.
I actually did an experiment years ago to see the difference for my self between a high pressure vs normal pressure feed. I used a regular pump and resovoir instead of a booster pump but still had my pressure around 60-70PSI. The difference in waste water was almost negligible compared to my normal operating pressure of around 40PSI. If your below 35-40PSI a pump could be good. I also think there is some merit for using one in the winter since temp is as much as a factor on RO production as pressure. Using one when you are above 35-40 PSI is a personal choice.
[quote=“Gordonious, post:1, topic:2239”]
So here is the list of things I am looking for.(hopefully I can get some feedback to add things to the list or cross things off)
75GPD(at least)
Two DI cartridges
Pressure Gauge
Float Valve
Drinking water T off (probably could add this on my own)
Membrane flush kit[/quote]
I can see the value of two DI’s, but not two membranes - unless you simply want to make water faster.
I’d spend my $ on an inline TDS vs. a pressure gauge.
If you’re going to have a drinking water T, simply run about 1/2 gallon through that (prior to making RO/DI) and you won’t need a flush kit.
Sounds like you want the Full Monty sytem! I think you want one with a 3 gallon drinking water storage tank for the sink or fridge. That is a presurized tank. when you have a pressurized discharge storage tank, you can get a PERMEATE pump added to the RODI to recycle the pressure and most of the waste water back to the membranes. and if you get a booster pump, you up the pressure of the input raw water for more efficiency too. Air Water Ice has one something like that. Im sure there are others. and of course you can get them with multiple membranes, DIs and TDS meters inline, with back flush kits and will even whistle Dixie!
Ellen I have a feeling I might be headed in the direction of getting a booster pump. While I have not needed one for my standard RO unit I think with a completely unit I may need one, especially if I go with dual membranes.
[quote=“logans_daddy, post:4, topic:2239”]
As far as PSI guages i dont think the are necessary. IF your PSI is up to par then its not likely to flucuate and monitoring it is almost pointless.[/quote]
I was told that you monitor the PSI after the prefilters and when they start to get clogged up the pressure will drop and you will know it was time to replace them. At least that’s what I took from something I was told two years ago… if memory serves me correctly.(which it often times doesn’t)
[quote=“logans_daddy, post:4, topic:2239”]
Let me know what you need the float valve for and i might be able to give you an idea. Also, usplastics sells the nicer float valve that typically goes for $12-$15 for $8.[/quote]
The float valve will be for topping off a 44gallon brute which I use to store my RO water. I mix my water in two smaller brutes and need to top off lots of tanks.(even if I ever get a couple of ATO working I still have tons of smaller tanks to top off manually)
was told that you monitor the PSI after the prefilters and when they start to get clogged up the pressure will drop and you will know it was time to replace them.
Maybe, i never thought about that before. i would think that your TDS would be effected WAY before the filters got clogged to the point that they would lower your PSI. of course i dont know for sure and could be wrong.
Jon, it sounds to me that you might be better off looking into a commercial unit. AWI has several including the one that DPA uses and they are relatively affordable compared to a standard unit with all the features your looking for.
I will talk to you off the board about the one DPA uses, but it is not for me.(OT) I’ll just say most of what you are paying for with that unit is getting more then 75g per day.
If crappy prefilters make an effect on the TDS of your output that means so much crap was thrown at you actual RO membrane that some solid has broken through it. TO me that sounds like an entry point for more crap to come through later. I believe waiting until the TDS of you output registers shortens the life of your membrane.
One might argue you should try testing the TDS before and after the prefilters, but I would recommend taking a look at what “TDS” means and what the prefilters are designed for.
[quote=“Gordonious, post:13, topic:2239”]
One might argue you should try testing the TDS before and after the prefilters, but I would recommend taking a look at what “TDS” means and what the prefilters are designed for. [/quote]
I loom at TDS right after the membrane before the DI and after the DI. If the TDS is more than 3-7 right after the membrane I know the membrane is declining because normal readings are 2-5ppm. As soon as it hits 1-2 after the DI I swap out the resins. I just automatically change my prefilters every 6 months.
[quote=“Gordonious, post:17, topic:2239”]
Anyone know of an easy way to check the TDS on my tap? Starting to think I may need a booster pump. [/quote]
maybe i just don’t understand, jon, but why don’t u put a tds meter in a glass of tap water??
