RO/DI Hare Brain Idea

<a href=showthread.php?s=&postid=11547942#post11547942 target=_blank>Originally posted</a> by manderx
i don't like bladder tanks in general because they make the RO work against pressure, but you gotta do one if you want it to feed a drinking faucet/icemaker.

i'd put the bladder tank on it's own branch with a check valve to feed just the icemaker/faucet and never feed the reservoir. no need to make the bladder tank refill constantly as it would when feeding the topoff reservoir also. though if the bladder tank is empty from draining lots from the faucet at the same time you are refilling the reservoir, i have no idea what would happen to the icemaker if it wants water and doesn't get it (i'd bet it's engineered to be fine).

no reason the topoff reservoir needs to be more than a few gallons. also, you can put a solenoid/timer on it to only refill the topoff reservoir once or twice a day to eliminate tds creep.

i'd use a cheap ebay peristaltic instead of a booster pump to move water from the reservoir to the sump.
Click to expand...

listen; I work installing/servicing RO systems, and the TSD creep is the biggest bunch of CRAP I ever heard, is like the Magnets for your JOINTS to relieve pain. BS!

we use bladder tank all the time, and the RO last 3-5yrs w/o problems, as long as a autoshutoff valve is installed the RO pressure is only during filling, and we set our tanks empty @10-12psi of air.

most of our membranes are 80gpd RO TFT membranes and they remove 95-99% of TDS our standard is less than 010 TDS, and this is for drinking water! we also use OZONE in most of our systems too.

check our site
www.taylormadewater.com
 
and the TSD creep is the biggest bunch of CRAP I ever heard...

...and the RO last 3-5yrs w/o problems
Click to expand...

tds creep has nothing to do with how long the membrane lasts. the ro relies on the pressure difference between the in and the out to compress the membrane to shrink the pores to get good clean water. when you turn a RO on and off, the first water to go through it gets through before it's fully pressurized and lots of solids get through. if you have a RO hooked up 24/7 to a float valve'd reservoir that feeds an autotopoff, it's going to turn on and off quite frequently to make only a few tablespoons or cups (depending on the footprint of the reservoir) of water at a time. this water will not be anywhere near as pure as water made once the RO has run for a while. it is documented in plenty of real articles, and you can even measure this yourself with a TDS meter. if you don't believe me, try it. make sure to read between the RO and the DI.


80gpd RO TFT
Click to expand...

what's TFT? i've only heard of CTA and TFC. who makes it?
 
Hi RandyStacyE.

I think you're getting way too complicated.

I run what jmc74 has depicted with the exception of the multiple bladders. I also don't bother with the DI canister.

I run the bladder tank under my sink. I run 40 feet to my tanks. I recommend you run 3/8" for your domestic but don't run that to your tank. Run 1/4". A hundred feet of 1/4" will haul more water than your system can make anyway. I do batch make-ups every few days. I turn on a valve at the tank. This gets me 3 gallons delivered in about 15 minutes. A benefit of the 1/4" avoids the whole drinking water side problem. There is just enough back pressure so you can always still get water at the sink(at least a glassful usually much more).

You certainly need djfrankie's pictured automatic valve.

This then would ditch the whole holding tank, booster pump stuff.

Put the DI canister just between the bladder T and the tank. You sure don't want to drink DI water.

Your slow float dribbling make-up will assure that your bladder tank remains at least 80% full as the automatic RO valve kicks on after about a 1/4 of the bladder tank volume is used.
 
<a href=showthread.php?s=&postid=11548303#post11548303 target=_blank>Originally posted</a> by kcress
Hi RandyStacyE.

I think you're getting way too complicated.
Click to expand...

I think you're right :)

I'll likely just ditch the the whole automated reservoir feeding the sump.

I'll just use an elivated 5-10 gal reservoir beside the tank inside of a cabinet or something. At least then I could just fill the reservoir once a week or so.
 
The first drawing is the way i would plumb it with the exception I would use float switches and a solenoid to combat TDS creep. Let the staorage barrel draw down several inches before starting the RO so you dilute the initial high TDS water.

I use a 14G pressure tank on my system (drinking, ice maker and DI usage) and still see the effects of TDS creep. My RO produces a TDS of 5.3 to 6.2 once it is running for a bit but the initial TDS may be much higher. My pressure tank climbs to between 14 and 25 after about two weeks so I make it a point to completely drain the pressure tank at least that often by making 25 gallons of RO/DI water in a single day to allow the tank to fill with freash low TDS water.
 
This is pretty much the exact setup that I run, and there are a few points worth noting.

First of all, when running with a tank and having it integrated into your drinking water, you're going to get massive creep. I GUARANTEE this.

I have putzed w/ every kind of shutoff valve available. I have tried five different kinds attempting to get the tank to drain significantly before RO production starts. No matter what, the delta will drop enough to have the flow start after a couple of cups is dispensed.

So after going that route, I ended up going w/ a creep water dump strategy. I sort of stole the idea off Donw.

I have the pressure switch for my booster pump engage a TDR that controls a three way solenoid. The waste and product tee at the one output of it. The solenoid then dumps all the membrane output (permeate and brine) down the drain for the first minute or so. After that, it fills the tank again.

Prior to adding in the solenoid, water coming out of my tank was running at a TDS of about 25. Now it is 1. I'm running triple membranes and have about 250 coming in. I additionally run a permeate pump to counteract the tank pressure and I have my booster running at about 75psi.


Pete
 
<a href=showthread.php?s=&postid=11549048#post11549048 target=_blank>Originally posted</a> by AZDesertRat
My pressure tank climbs to between 14 and 25 after about two weeks so I make it a point to completely drain the pressure tank at least that often by making 25 gallons of RO/DI water in a single day to allow the tank to fill with freash low TDS water.
Click to expand...


Funny that we got pretty much the exact same numbers.

Only took my 3gallon tank about 2 days to get that high though. :)
 
Float valve in the sump is a bad idea. They are prone to salt creep and as such and can stick in the open position fairly easily. Should that happen the sump will overflow and possibly lower your SG enough to kill the tank if not caught quickly.

I've seen a simple ATO at Phishy Business that you plug a pump into, it works on air pressure like a washing machine level control and shouldn't be affected by salt creep. The ATO can be set on a timer so it only runs a couple times a day limiting the amount of water allowed in at any one time. The cost is about $60 ( http://phishybusiness.com/store/product_info.php?cPath=28&products_id=207 ). They also have one with a solenoid valve and JG fittings to run 1/4" polyethylene tubing directly from the RO unit to the valve then to the sump, no holding reservoir required. You can set it on a timer too to accomplish the same thing. About $100 for this one ( not on the website ).

Personally either way I'd install a valve at the output to limit how quickly the makeup water can flow from the ATO into the sump.

I've yet to get either one since I don't have a convenient place for a holding tank and no way to run tubing from my RO's current location to the tank. I am however leaning toward a trash can in our furnace room with a small power head (I already have a Mini-Jet 404 set up with a JG fitting) controlled by the $60 ATO and a timer and feeding a kalk reactor.

I'm not sure in this case if a pump that small will do the trick but a booster pump seems like overkill for an ATO. Since a lot of your equipment has to be in a crawl space I'd think the solenoid version would simplify things for you.

Tim:cool:
 
<a href=showthread.php?s=&postid=11547997#post11547997 target=_blank>Originally posted</a> by jmc74
listen; I work installing/servicing RO systems, and the TSD creep is the biggest bunch of CRAP I ever heard, is like the Magnets for your JOINTS to relieve pain. BS!
Click to expand...
 
I would guess he has not been working there long and has never bench tested a membrane. All membranes have TDS creep regardless of size, type or brand, its a fact of life we have to deal with. When a membrane is sitting in a dormant state the pressures and TDS tend to stabilize on both sides thus higher TDS intially until you expel that first bunch of water. Spectrapure has developed a way to reduce the effects with their new Ultra High Efficiency system. They flush the membrane with DI water and it sits in DI when not in use so it keeps the membrane flushed well. Thats the only system of its type I am aware of.
 
I do know that TDS Creep is not a myth. I was going to attempt the TDS creep problem after I figured out how I was going to set this deal up.

I was actually contemplating doing DonW's idea too! :)

I am almost completely 'electronic illiterate' so the timing portion for me would take some time for me to comprehend ... and how to wire it.

It's funny, I have approx 250 TDS incoming with my well water. I run two 75 gpd membranes and I do have an inline TDS meter. When my RO kicks on I can get up to approx 60 or more TDS and then it will steadily drop down to around 2 TDS. This leads me to believe that a 'pass-to-drain' system would work for me.

A dilution method doesn't appeal that much to me (multiple float switches in the reservoir), but I'll definitely consider it.
 
<a href=showthread.php?s=&postid=11547997#post11547997 target=_blank>Originally posted</a> by jmc74
listen; I work installing/servicing RO systems, and the TSD creep is the biggest bunch of CRAP I ever heard, is like the Magnets for your JOINTS to relieve pain. BS!
Click to expand...

maybe I should have put some magnets on my DI housing before. ..they may have kept my resin from disappearing before my very eyes. :lol:


If you would like to try out the solenoid setup, I could get a list of parts together and we could work it out. :)

Pete
 
<a href=showthread.php?s=&postid=11549951#post11549951 target=_blank>Originally posted</a> by wife no likey
maybe I should have put some magnets on my DI housing before. ..they may have kept my resin from disappearing before my very eyes. :lol:


If you would like to try out the solenoid setup, I could get a list of parts together and we could work it out. :)

Pete
Click to expand...

Thanks! I will keep that in mind and I appreciate the input.

I'm gonna have to think about about this whole setup. I will be using my unit for the kitchen, but It's going to take some time to figure out a practical way to keep a reservoir in the crawlspace for water changes.

I don't mind pumping water up to the main level to fill a temporary mixing station. I just have a lot on my plate with this one.
 
If you put the trash can in the crawl space with a pump you can use it for mixing saltwater, if you put the check valve between the tank and drinking water bladder tank, and still have drinking water while the trash can is refilling. You could just connect the RO to sump with a float and have an extra float for the trashcan with a pump in it to bring you water for water changes. Or, if you can swing the money get a 40 gallon pressure/bladder tank, skip the extra trash can completely. Then you could drain out 30 gallons or so of water to mix without depleting your total reserve of water. plus with a larger pressure tank, TDS creep should be less of an issue also. Then plumbing would be a lot easier also, just one tank with multiple T's feeding drinking water and tank and an outlet for mixing station.

Kim
 
<a href=showthread.php?s=&postid=11548053#post11548053 target=_blank>Originally posted</a> by manderx

what's TFT? I've only heard of CTA and TFC. who makes it?
Click to expand...

my bad, I didn't check my typing it is TFC, I guess I got too excited

:lol:

oh, and the RO creep, I have seen it on RO's that equalize only after been off for a while, but if you are using the system on a top off and also for drinking water the membrane will stay pressurized for the most part, as the auto shutoff will close when the tank is full and no more water can enter the system, so the auto shutoff closes and the RO and filters stay on pressure, just not flowing, so it is static pressure. we have few customers that run RO water on labs, for either Medical, Chemical or Industrial, and we have tested the TDS creep, because they want the purest water without going to DI or Distilled. so yes they are papers on the effects of equalization of the membrane, but when plumbed correctly you will not see an increase of TDS. or the most I personally seen is a system that produced a TDS of .002 on a supply of .366 TDS and the creep set up the TDS after 12hrs of the RO being off at .008 for few seconds or about 3oz. and this was on a membrane that was about 2yrs old.
 
Why not use the waste water for your drinking water. The first two filters are better then any refrigerator filter will be. I have heard drinking lots of pure RO/DI water can actually be hard on your stomach, as it has no minerals at all. I don't have any facts to back that up, but in does make some sense, as pure RO/DI is supposed to be the most universal acid there is. By that I mean it dissolves more materials then any other acid. That is how it has picked up all the minerals, salts and everything else we strip out for our fish. I would love to see some real facts on this.
 
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