low ro/di output. please help

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arowanaman420

Aquarium Advice Apprentice
Joined
Dec 25, 2004
Messages
39
Location
AUSTIN, MN
I've had my 6 stage 125 gpd ro/di unit for a while now, and it just doesn't put out much water. We're talking like 1/2 gpd output here. It's the first thing in line when the cold water comes into the house, so I don't think it's a pressure issue. Now that I have 150 gal worth of tank water it hardly keeps up with evaporation. Is this normal? What can I do? I'm about to scrap the whole thing and go back to buying my water.
 
I imagine one of your stages is blocked for some reason. I sure would try to find the reason because I buy mine and it ain`t no cheap adventure.
 
I have checked water flow at every stage. The pressure seems acceptable until it reaches the ro membrane. The good water barely drips out while the rejection water flows fairly well. I have gone as far as disconnecting everything and just running through the ro filter with no noticeable change in output.
 
How cold is the water coming into your house? Probably pretty cold up the in MN now. :eek: I'm pretty certain you get a lower output of good water at colder temps.
 
How old are your filters? They should be replaced about every 6 months. Do you have a pressure gauge? If not I would suggest in getting one if your unit will accept it. The pressure needs to be at least 55 psi to get your rated GPD, sometimes more depending on your RO membrane. How old is the RO membrane? Those need to be replace every 3-5 years. You may also want to look into getting a flush kit, to clean the membrane so it will last longer.
 
from the data Ive read on RO membrains the output to production seems best around 65 PSI the preasure gage helps tell you when its time to replace the prefilters so its a good investment if you dont have one already.. but it sounds to me like your being affected by cold water.. check out greenfish's link.. the water being too cold can effectively reduse your output to almost nothing.. and that seems to be the problem here..
good luck (y)
 
If your water is very cold, the pores in the RO membrane will shrink, leading to better rejection of waste, but much lower output flow.
 
It sounds like you have a problem with the RO membrane to me. I have well water which is cold and I still get around 40 gallons a day. It should not slow down to 1/2 gal a day. That is worthless.
 
I have hot and cold water plumbed into my RO. I think you are wasting your time trying to warm the water. Is this filter new?
 
Has it always put out the same amount? If so then it is probably your pressure and or cold water. I have pressure that runs at a low of 35 and high of 55 and my water is well and very cold so I hooked up a Y hose on my washer outlets and run some hot and cold together. This helped my out put, and no, the warm water did not do anything to the final out put.
I was burning the DI resin faster this way so I got a 8800 booster pump. WOW what a difference that made 80 PSI now., I crank out 5 gallons an hour and I have been using the same resin and filters sense May. Still producing 1 on the TDS meter..

I would first look into a pressure gauge and see what your really running.
 
Tried the warm water trick. That helped a little, but my basement is so cold that a 150w heater can't warm 5g of water sufficiently. I started off by filling the bucket with the hottest water I could get from the tap. I noticed my output increase after this, but the water won't stay warm. I think I'm suffering from low pressure as well. Even when the water in the bucket was hot I wasn't getting the kind of output you guys are talking about.
 
how warm is the water in the bucket with the 150W heater?
the numbers are more like 5 gallons per hour on a fast unit so it doesnt appear to be alot of output when its operating correctly..
and yes you really need to check the preasure.. that too will really harm performance..
HTH
 
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