RO/DI Unit making less water than expected?

Zup, guys and gals!?

I bought today an RO/DI unit for $100, brand new! It's not the one with 3 canisters, only 2, but I was told that's all you need.

I hooked it up later after I got it and made all the connections right, I'm pretty sure.

The thing is making very little water though. It pretty much feels like I'm drip acclimating my 5 gallon bucket. Is this normal? I thought there would be a stream of some sort coming out, but it's only drip after drip, constant and steady but drip after drip. Since I'm new to this technology, I would appreciate your experience with these devices. I read the delux version (the one with 3 canisters) has a "power pump" which sounded like an easy to do mod, but the problem is I don't have a plug under the sink, or near it that my wife would put up with if something is plugged to it 24/7. Do you think a bigger diameter (bigger than 1/4" OD) would help?

In the instructions, it mentions the possibility of connecting the output to a water faucet, how is that ever going to get any water out a faucet dripping like that?

Well... maybe there's some sort of pressurized container I need for that.

Please, let me know your experience if you have a unit like mine, it's a Puratek Aquarium RO/DI unit. http://premiumaquatics.com/store/merchant.mvc?Screen=PROD&Store_Code=PA&Category_Code=&Product_Code=VX-RO-PV100
It only had the pressure gauge but it's right below 40, which is the minimum recommended working pressure. Should that make a big difference?

Well... too many questions already, so.... let's see what the community has to say about this unit! All comments welcome!

- Mag.

 

yes, the input pressure makes all the difference. your home should be getting somewhere around 60-70PSI hopefully. if you do not have this type of pressure where you have the unit hooked up you require a device to increase the input pressure, a pump.

i shut the water main to my home, cut the fittings, put a T, a valve, and then setup my RO unit directly off of that main connection. looking at my gauge right now, 72PSI. 196TDS on the input and 0TDS on the out.

not sure if yours came with a TDS meter or not. at any rate, you'll need to get that pressure up over 40. im not sure what you hooked it up to.

 

oh, and yes mine is a constant stream of water coming from my unit. and the waste water output as well.

 

It's hooked up under the bathroom sink. I don't have many options in these apartments. So I was left with the sink, inside the vanity. As you know, there's a hot and cold water with valves that hook up to the faucet. In my setup, I took the cold water hose and added the "T" with the high pressure valve that feeds the RO/DI unit.

Mine doesn't have all the fancy meters. Just the pressure gauge. I just couldn't spend more than the $100 bucks I paid for a unit. I doubt also I'll be able to hook up a pump to help pressure, but I'm thinking that as long as I can make 5 GPD I'm set. I only do water changes on the weekend, so I can start filling buckets early in the week. I was just hoping I didn't need to connect this thing to the main pipe to get decent pressure, but it seems to be the case... I suppose you don't need really that much pressure in the sink.

 

it will speed up after you get through a few gallons and the membranes get all saturated

 

I don't know if this info will help you, but here goes. I bought my unit and planned on putting it under the kitchen sink upstairs. My kitchen sink didn't have very much pressure and so I moved it to the laundry room and hooked it up to the clothes washer faucet with a garden hose splitter. It worked better but still not 50gpd like it was supposed to be. After a month of frustation I finally called coralife and they said my TFC membrane sounded like it might old from sitting on a shelf for to long. They sent me a new one no questions asked. It works great. Anyhow I ran the waste tube into the washer drain and sometimes run it in to my washer itself so I don't waste any water. I just mounted the unit on the back wall and it is totally out of the way. I hope there is something useful for you there.

 

Maybe I need to put a "T" before the valve that goes to the faucet instead of after the valve. I'm sure that kills a lot of the pressure.
I went to HD and Lowe's and they didn't have a float valve. Bummer! Any other place that could have these?

 

First off, you have an RO only not an RO/DI.
The unit you have is pretty standard as far as RO units go, it has a prefilter, carbon block and RO membrane with the addition of a pressure gauge which is good.
Personally I would change the prefilter to at least a 1 micron if not a 0.5 micron to match the carbon block so it does not get fouled or plugged by all the particulates and colloidal materials a 5 micron nominal rated filter will allow to pass. You always want your prefilter and carbon block to be approx the same micron range so you protect the more expensive carbon block which in turn protects the very expensive RO membrane.

Compare yours to the CSP unit found here for $135 including the pressure gauge but also including the better prefilter, better carbon block, tested RO membrane and an inline TDS meter, or for $10 more you get a full size vertical DI with the CSP-DI.
http://www.spectrapure.com/email/customer-appreciation.html#1

Two things have a major effect of GPD output and a couple others have smaller effects. Water pressure and wate rtemperature are the two major factors. The GE Water 100 GPD RO membrane gets its 100 gallons per day rating at 65 psi incoming pressure and 77 degree F water temp. If one or both are lower than the specified numbers then production will be lower. Lower pressure also produces higher TDS since the filter does not work as well.
Do you know your water temperature? Right off we know you ahve 40 psi so that by itself already cuts the production to about 65% of the rated 100 GPD, if you have cooler water it will be even less. Say you have 60 degree water rather than 77 degree, your output will now be about 75% of that 65 GPD or about 50 GPD. 50 GPD over a 24 hour period is about 2 gallons per hour or about 2 ounces per minute. Your steady drip is about right.
You might want to check your waste ratio, at lower pressures and colder waters the waste goes up significantly which means you have less pressure available to the membrane making the situation worse. use a measuring cup and time 250 mL first from the good line the time 250 mL from the waste line. It should be 4 times longer for the good than the waste but I suspect you are wasting much more so it will fill quicker, probably 6:1 waste or more. This can be fixed with an adjustable flow restrictor or a capillary tube restrictor you trim for your exact water conditions. About $5.

Installing a tee really doesn't do anything for you, we are talking about a quart per minute tops including both waste and good flows so you can get that out of a pinhole.

Try pinching off or kinking the ends of both the waste and RO lines and see what the pressure gauge rises to. If it rises to say 50 static then you have too much going to waste and could benefit from the above, if it doesn't change or changes little then you are stuck with low pressure and a booster pump might be in your future. Whatever you do NEVER ever try to blend hot and cold water to increase the production, this is the quickest way to ruin a membrane there is. Remember being in the shower when someone flushed the toilet or starts the clothes washer, you got scalded and thats what happens to the membrane. it cannot take anything over 113 degrees F or it melts. Plus warmer water does not treat as well and will increase the TDS in the finished water, colder water is more dense and treats better.

 

Wow.... highly informative and impressive!. Thank you so much for the help. Do you think I ban buy an extra canister and make this an RO/DI unit? I do have a little extra space under the sink.

You were right about the water production. It started to speed up a little bit, but my water pressure from the only one spot I can install this is very low (40psi). But unless this is going to ruin my membrane or filters I don't mind. I can make more than 5 GPD and that's sufficient for me.

I wish I seen the RO unit here. It was a compulsive purchase since I got really frustrated carrying water buckets up and down the stairs to my apartment.

Thank you very much for sharing your knowledge! Very helpful post indeed.

I'm about to order a float valve from one of the websites you posted on a different thread. It would help me greatly if you'd help me order whatever I need to make this unit an RO/DI unit. I have absolutely no experience with these and didn't even know the waste valve was supposed to be open. I had it capped off since I could not find anywhere to drain it. I't's now discharging water in the sink, which she won't like. I'll have to figure something out for that.

- Mag.

 

My RO/DI unit was soooo slow when I first installed it. Making the 90+ gallons for my new tank was a horribly excruciating process. Lol But now that I've used it several times the water output has really sped up. Now I get 5 gallons in an hour and half.

I've been told along with pressure, another thing that effects the output of the water is the water temperature. Really cold water is slower. That's what someone told me. And I'm inclined to believe it, because my water is ice cold, and it is a little slow.