Ro Membranes Work Better In Colder Or Warmer Water?

[DanMan092]

Hey guys. I was using a 24? gph RO membrane and we currently bought a 50 gph. We were using the 24 with cold water, but the 50 from warm. The 50 is giving out less water. Could it be that since the 24 was like 10 years old that it was not filtering good?

 

[Lynden]

Well, in warm water, the salinity in marine tanks is lower. But this contradicts your problem. This takes only logic to figure out, i'll post my thoughts as soon as they come.

Sorry i cant be much help now

 

[Opcn]

RO membranes work faster in warm water, the incresed kinetic energy of warm water causes molecules to find there way throught the maze faster.

 

[Lynden]

Excellent, took the words right out of my mouth.

 

[DanMan092]

All right! But it's been on for like 18 hours and we only have like 10 gallons of water...

 

[Opcn]

Is the system set up properly? do you have enought back presure? Are all your prefilters working correctly? Is your postfilter clogged? Maybe you got a bad membrane, that does hapen on occasion, if the system was used someone might have run it without a sediment filter and clogged it up.

Hope you figure it out

Well, in warm water, the salinity in marine tanks is lower. But this contradicts your problem. This takes only logic to figure out, i'll post my thoughts as soon as they come.

Sorry i cant be much help now

I have no idea what this is in reference to, the SG of saltwaer is the same in cold water regions, being probably the only one here who has ever dealt with a cold water system I can tell you, its the same water, just a different temp and different levels of nutrients based on location.

 

[Ed4567]

Well, in warm water, the salinity in marine tanks is lower.

Salinity is an absolute value that doesn't change with temperature. However the specific gravity of water with a particular salinity will be lower at higher temperatures.

 

[Navarre]

OK am i to understand that you are using an ro unit on a hot water supply and a cold water supply?

If so then i would recomend that you stop doing this. )

A Hot water supply is usually atored in a hot water tank and thus you have very little back pressure to be able to push through the membrane when compared to the backpressure of a coldwater tank.

Also a hot water tank is full of crap and sediment at the m ttom so your RO unit will clog up faster. I also dont lusing warm wter aroud copper pipes in case it brings in even more minerals and of course deadly copper.

I might be wrong but as of yet i hav enever known anyone use an RO unit on warm water. its safer to use cold water and heat it after.

 

[Opcn]

You get the optimum flow at about 80 deg F, thats warm, if you use a hot water suply line you can melt some of the components, also optimum flow and optimum purity never walk hand in hand.

 

[Lynden]

Well, in warm water, the salinity in marine tanks is lower.

Salinity is an absolute value that doesn't change with temperature. However the specific gravity of water with a particular salinity will be lower at higher temperatures.

Well, actually, in a previous topic, I stated that I found my heater unplugged, and the water was very cold.
The specific gravity and, in fact, the salinity too was slightly higher than the same water warmer. The water reacted much differently to fresh water when it was cold, although that does not nessicarily prove that the salinty was higher. But by salinity, I actually meant specific gravity in my original post, I tend to say salinity when i mean sg.

Getting back on topic, when RO is used by the army, ect. it is in a massive tank with extreme back pressure. It is used in warm river, in colder water it is less effective.

 

[steelhealr]

Added comment..if the unit is old, you'd better invest in a TDS meter, or total dissolved solids meter. As a membrane gets old, it fills with material. The pressure increases in the unit and output decreases.....mineral content in the O/P water goes up. The membrane may need to be replaced. Also, some homes have low pressure and water o/p is less than rated. There are pumps that you can buy for the RO unit to increase o/p. SH

 

[DanMan092]

My dad said something about it making 50 gals a day with 65 lbs of pressure, and our house has about 50 lbs. We probably have about 15 gallons right now, my dad turned off the water thinking my mom would neglect it Oh well, I have time!