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#1
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How long does your RO membrane last?
I currently have a Filmtec 75gpd RO membrane and it only last for about 700g. Is this normal? I'm not sure.
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Starting date: 12/07/03 2 - 250w MH RR 90g tank 20g sump 10g fuge 90lbs. LR 120lbs. LS 2 Clown~3 Chromis~1 Yellow Watchman~1 Purple Fire Fish~1 Scooter Blenny |
#2
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WOW, something isn't right. It is impossible to say how long a R/O membrane will last because it is a filter. Garbage in/ Garbage out. Unless you have well water, and your TDS is out of site I'd say there is no way to exhaust a membane after only 700 gallons. I'd say 10 times minimum that would be closer to normal. Perhaps much more. What are your TDS out of the mebrane now? How about out of your tap?
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" high tide raises all ships equally" |
#3
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Its definitely not normal!!!! I'm going on 2 yrs with my RO unit with the original membrane. Do you have a TDS meter? I have a hand held one you could borrow if you want. Pm me if you like
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Patience, something my reef teaches me every day... |
#4
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Some people run warm water through their ro, so it ready for top off. That will damage the membrane.
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#5
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You running barebones w no prefilters??
Are you running at least 1 and hopefully two stages before the Membrane???????????????
If you are barebones with no carbon block and no pre-filter in 1 and .05 micron then you will hammer your membrane fast. IE the membrane is doing all the work. (1/2 micron is not required and is probably excessive by most BTW) For example MY RO/DI setup. I have 1micron, then 1 micron carbon, and 1/2 micron then membrane, then DI stage 1 and DI stage 2 OR do you have the tubes going the correct route. Get up to 4 and 5 stages and same color tubing and in a hurry during setup you could have bypassed other stages. ???
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Two little old lady's are sitting on a parkbench and the one little old lady says " My Butt Fell Asleep". The other little old lady yells back " Oh Yeah...Well A Minute Ago It Was Snoring!!" |
#6
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Why do you think the membrane has gone bad?
Russ
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RO/DI equipment and supplies at www.BuckeyeFieldSupply.com Sales@BuckeyeFieldSupply.com |
#7
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Because my DI resin goes bad really quick.
__________________
Starting date: 12/07/03 2 - 250w MH RR 90g tank 20g sump 10g fuge 90lbs. LR 120lbs. LS 2 Clown~3 Chromis~1 Yellow Watchman~1 Purple Fire Fish~1 Scooter Blenny |
#8
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I would borrow Cove's meter and test
I would take Cove Beach up on his TDS meter offer. I would remove DI resin out of that stage.
Then I would charge it back up and let 10 or so gallons go through then test the output to double check the RO membranes output before you bring in a verdict.
__________________
Two little old lady's are sitting on a parkbench and the one little old lady says " My Butt Fell Asleep". The other little old lady yells back " Oh Yeah...Well A Minute Ago It Was Snoring!!" |
#9
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Thanks for the offer. I have a TDS meter myself. If the membrane is bad, the water coming out without the DI stage would essentially read the same as the tap water, right? If it is still good, what reading should I approximately get? Thanks for everyones input!
__________________
Starting date: 12/07/03 2 - 250w MH RR 90g tank 20g sump 10g fuge 90lbs. LR 120lbs. LS 2 Clown~3 Chromis~1 Yellow Watchman~1 Purple Fire Fish~1 Scooter Blenny |
#10
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If you have the 75g filmtec membrane and it is in good working order and you have 300ppm coming out of your tap, you should have about 6-10 ppm after the RO membrane. After DI it should be 0ppm.
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#11
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math sounds good
__________________
Two little old lady's are sitting on a parkbench and the one little old lady says " My Butt Fell Asleep". The other little old lady yells back " Oh Yeah...Well A Minute Ago It Was Snoring!!" |
#12
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The thing that kills RO membranes is chlorine, then particulate matter that fouls it. How old is your carbon stage and have you tested the post-carbon water for chlorine breakthrough? Do you have a solid carbon block or a granulated carbon filter?
The other thing that can kill your RO membrane is letting it dry out. |
#13
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The carbon blocks are solid. I have the typical 5 stage RO/DI system. How can I ensure that the membrane stays wet? I have a 30g trash can that I fill with water when it gets empty. I fill it about once every 1.5 weeks. Is there a problem in doing this. Can the membrane dry out during this period.
__________________
Starting date: 12/07/03 2 - 250w MH RR 90g tank 20g sump 10g fuge 90lbs. LR 120lbs. LS 2 Clown~3 Chromis~1 Yellow Watchman~1 Purple Fire Fish~1 Scooter Blenny |
#14
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Measure the pre and post RO TDS. See what percent it is removing.
TDS meter wont read chlorine or chloramine. More likely you just need to replace the DI resin. Russ from BFS (posted above) really knows his stuff.
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Ever get the feeling some people might be taking a fish forum just a little too serious? |
#15
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I also only run mine about twice a month but its hooked to water supply the whole time with a ball valve on the supply I use to turn it off.
If you unhooked it like from a faucet adapter it maybe able to drain back? I know the pure water outlet on mine is always open, and it doesn't seem to drain.
__________________
Ever get the feeling some people might be taking a fish forum just a little too serious? |
#16
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Quote:
I have a 100ft coil of tubing inside my sump before the RO unit to help bring the input temp up from the underground temps and it also helps cool the tank water.
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It doesn't make a difference what temperature a room is, it's always room temperature. ~ Steven Wright |
#17
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77 degrees is perfect. You can run into trouble if folks are imprecise in heating the water and occassionally feed HOT water to the membrane.
Russ
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RO/DI equipment and supplies at www.BuckeyeFieldSupply.com Sales@BuckeyeFieldSupply.com |
#18
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As said above, report your tap water tds and your RO water tds. Also - what is your waste to permeate ratio?
Russ
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RO/DI equipment and supplies at www.BuckeyeFieldSupply.com Sales@BuckeyeFieldSupply.com |
#19
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Quote:
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#20
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I just wish the tubing I have in the sump was titanium instead of plastic tubing
I'm guessing it doesn't transfer heat very well. Found this to answer your question about mixing hot/cold water. "Membrane performance is based on feedwater temperature of 25°C. For every 1°C below 25°C product water quantity is reduced by 3%. When feedwater temperature is regularly below 25°C, it is recommended that hot and cold water are mixed to increase the temperature to 25°C. Feedwater which is greater than 35° will damage most membranes. " Just guessing that the input water temp from the cold water supply line would hover around 50F in the winter means that 50F= 10C. 25C- 10C= 15C difference from optimal temp. 15C x 3% reduction in product water per degree = 45% reduction in output water To me it seems that it may pay off to run some hot and some cold in your case.
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It doesn't make a difference what temperature a room is, it's always room temperature. ~ Steven Wright |
#21
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just a note if you mix hot and cold and somone flushes the toilet or anything it will change and burn your membrance rate up i found out the hard way, also now that i run pure cold water i dont notice much more waste so just run cold water and put a heater in it,
my tds out of tap is about 130-145 and after the membrance i see 0-1tds i quit using the di unit sense i am just a fowlr no sense in paying all that in refill for di as it dont last long for some reason? Hope i helped a little |
#22
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There is a nice calculator available where you can plug in your water temperature and water pressure and it will calculate what your membrane should be producing.
Russ
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RO/DI equipment and supplies at www.BuckeyeFieldSupply.com Sales@BuckeyeFieldSupply.com |
#23
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Running the tubing through the sump first is a great ideal But unless you're dealing with heavy evaporation, I doubt it would do much cooling. Doesn't matter that the tube is made of plastic because the flowrate through the tube is so slow. I'm sure that the water in the tube is heating up very close to aquarium temperature before hitting the membrane.
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Your tastebuds can't repel flavor of that magnitude! |
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