RO/DI unit question

JoeRonda

Made in the U.S.A.
Has anyone ever gotten a rodi unit that let impurites through? I've got a tds meter on the way,but right now i've got an new tank with a major algae problem, a rodi unit that hisses when it's making water, and a sneaking suspicion that something is wrong with my coralife ro/di unit. Has anyone heard of a unit hissing like this before? Sounds like it's coming from the membrane housing. I've got it hooked up to an old spicket in the basement and I turn on the cold almost all the way and then the hot a little above half to warm up the source water a bit. Any thoughts on this?
Thanks,
Joe
 
I'd suspect your RO membrane is compromised and leaking. Did you ever allow the water to get too hot ? Hot water will cause an RO membrane to fail.
 
Does it leak anywhere? Hissing usually indicates a leak, possibly an improperly seated housing or a leaking water line.
 
I'd suspect your RO membrane is compromised and leaking. Did you ever allow the water to get too hot ? Hot water will cause an RO membrane to fail.

You could try reseating the membrane to make sure it has a good seal in the housing. Be sure to clean it out and also (very lightly) grease the seals with some silicone grease.

Otherwise, +1 on the membrane rupture. You should replace your membrane at lease every 2 years and often earlier.
 
Thanks for all the info. The unit is fairly new, 6 mo. old, and it has always hissed. I will try to reseat the ro membrane and lightly grease the caps.
 
Does it leak anywhere? Hissing usually indicates a leak, possibly an improperly seated housing or a leaking water line.

It does not leak anywhere. I've heard some people say that the amount of water pressure could be the cause of some hissing, and other people say that they have never heard of a unit hissing and I am just waiting to get the in-line tds monitor in the mail so I can see for myself just how pure the product water is that is being produced.
Thanks for the reply,
Joe
 
Does it leak anywhere? Hissing usually indicates a leak, possibly an improperly seated housing or a leaking water line.

That is a possibility and it wouldn't necessarily leak if it were sucking air into the unit (kinda like how a venturi works).
 
Okay, now this is weird, I pulled the membrane, made sure it was seated properly, and greased the o-rings. Now the unit isn't producing any waste water, only product water. This is a head scratcher !!!
 
most ro units make some type of noise when water is being forced through the membrane, the most noise is usually from the restrictor though.

a TDS meter is a must for ro/di units, are you running di resin?

most di resins will remove all impurities, even if your ro membrane is not working correctly.
 
most ro units make some type of noise when water is being forced through the membrane, the most noise is usually from the restrictor though.

a TDS meter is a must for ro/di units, are you running di resin?

most di resins will remove all impurities, even if your ro membrane is not working correctly.

yes, coralife ro/di 4 stage 50 GPD, the HM DM2 Dual in-line tds monitor is on it's way. I can't wait to see what the readings are. I bet I hurt the membrane when the washer stole all the cold water one time when i was making water and the unit filled up with hot water. I quickly emptied all the hot water out and now i just use cold water. I wonder if that was enough to harm the ro membrane? I guess the tds will tell !!!
 
most ro units make some type of noise when water is being forced through the membrane, the most noise is usually from the restrictor though.

a TDS meter is a must for ro/di units, are you running di resin?

most di resins will remove all impurities, even if your ro membrane is not working correctly.

Quick question EastBayReefer, what restrictor are you referring to? Because the noise I'm hearing is definitely coming from the waste water outlet from the ro membrane housing.
 
It's supposed to hiss. I had to look into this last nite when I went to make water at 1am and heard it hissing for first time real good. ( always thought it was water making noise).

It's the flow limiter on the waste line hissing. It's a plumbing feature called an 'air gap" and it's perfectly normal.
 
Okay, now this is weird, I pulled the membrane, made sure it was seated properly, and greased the o-rings. Now the unit isn't producing any waste water, only product water. This is a head scratcher !!!

Sounds like a problem with your waste line or line restrictor. Not sure how it connects, but try reversing it just to clean it out.
 
i had a hiss on mine and it was a line not all the way seated it never leaked water but it hissed from the air getting in. also my restrictor or flow limiter hissed try guest taking that off to see if thats it. you dont need it unless you have an ATO
 
It's supposed to hiss. I had to look into this last nite when I went to make water at 1am and heard it hissing for first time real good. ( always thought it was water making noise).

It's the flow limiter on the waste line hissing. It's a plumbing feature called an 'air gap" and it's perfectly normal.

OK, thank you very much, it's about time someone tells me it's normal. I was starting to wonder. Now is it because of the DI stage, because everyone that tells me that their's are silent only have an RO unit?
 
i had a hiss on mine and it was a line not all the way seated it never leaked water but it hissed from the air getting in. also my restrictor or flow limiter hissed try guest taking that off to see if thats it. you dont need it unless you have an ATO

The restrictor is built in to the waste water outlet elbow. I just got off the phone with Coralife, yeah they returned my call from earlier today, pretty good customer service, and they told me that it is normal for the ro membrane's housing to hiss at the waste water outlet fitting. So all this time of being told that there was a problem was all false alarms. Thank goodness, I was about to buy like a Kent or Aquaticlife, and all along my Coralife has been nothing but good to me !
 
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