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View Full Version : When to change RO filters?


Coralgurl
12-17-2012, 01:00 AM
I have had my RO unit for a year now, tds meter is reading 9, guessing its time to change filters?

kien
12-17-2012, 01:05 AM
I change mine whenever I get a non zero TDS. Ranges from 8 months to a year depending on how heavily I've been using it.

Coralgurl
12-17-2012, 01:36 AM
Ya, thinking this is what's causing issues in my tanks ATM...will pick up new ones tomorrow!

mike31154
12-17-2012, 04:15 AM
Certainly your output TDS is an indicator, but it also depends on how your system is put together (how many stages, pre filters, rating of the membrane etc), the TDS of your source water & how you run it.

If you have clear pre filter housings you have a visual indicator of how those are doing & being relatively inexpensive, they can be changed more often without worrying whether they are completely clogged or not. The more pressure (within specs) that your membrane sees, the better & clogged pre filters, including the carbon stage(s) all drop the psi before it gets to the membrane.

I use two pressure gauges on my system, one at the source showing house pressure & one at the RO membrane (after the pre filters). Whenever I run the system I keep track of the difference between the two pressure gauges. Once the split rises by a given amount, usually 3-4 psi, I change the first stage pre filter, a 5 micron. I run a 1 micron pre filter after that, followed by the carbon block which is rated for a throughput of thousands of gallons. I only recently changed the carbon black after a couple of years of use. Also keep track of total gallons through the system to give an idea of when the carbon is getting close to it's rated capacity. Just in case, I keep a swimming pool test kit handy that has strips which include chlorine detection.

A few months ago the TDS out of my DI stage started showing 1, so that's when I changed out the DI media & also the carbon block, since it was nearing it's rated thruput. I'm still on the same RO membrane since buying the unit new almost 3 years ago. With 210 TDS tap water, the 75 gpd membrane still gives me 1 TDS out 3-4 minutes after start up.

Willito
12-17-2012, 04:38 AM
Regardless what your TDS is, if you are using this filter system for drinking purposes it is best to at least change it out every six months. Just to be cuatious, the bateria build up on the filters are eliminated this way. If you like the taste of the bateria then just follow your TDS readings.

Seriak
12-17-2012, 04:49 AM
How do you tell when you membrane needs to be changed?

Coralgurl
12-17-2012, 04:54 AM
Certainly your output TDS is an indicator, but it also depends on how your system is put together (how many stages, pre filters, rating of the membrane etc), the TDS of your source water & how you run it.

If you have clear pre filter housings you have a visual indicator of how those are doing & being relatively inexpensive, they can be changed more often without worrying whether they are completely clogged or not. The more pressure (within specs) that your membrane sees, the better & clogged pre filters, including the carbon stage(s) all drop the psi before it gets to the membrane.

I use two pressure gauges on my system, one at the source showing house pressure & one at the RO membrane (after the pre filters). Whenever I run the system I keep track of the difference between the two pressure gauges. Once the split rises by a given amount, usually 3-4 psi, I change the first stage pre filter, a 5 micron. I run a 1 micron pre filter after that, followed by the carbon block which is rated for a throughput of thousands of gallons. I only recently changed the carbon black after a couple of years of use. Also keep track of total gallons through the system to give an idea of when the carbon is getting close to it's rated capacity. Just in case, I keep a swimming pool test kit handy that has strips which include chlorine detection.

A few months ago the TDS out of my DI stage started showing 1, so that's when I changed out the DI media & also the carbon block, since it was nearing it's rated thruput. I'm still on the same RO membrane since buying the unit new almost 3 years ago. With 210 TDS tap water, the 75 gpd membrane still gives me 1 TDS out 3-4 minutes after start up.

My water coming in has a tds of 110, my last batch of water going out was at 9. I've got a vertex RO unit, no di. I haven't monitored the gauges at all, it has 2, but I never look at them....as for how the canisters look, I can't see a visible difference but again, probably not paying attention from initial set up.

I've noticed HA growing on my cheato and in my emerg overflow, plus I've I've an outbreak on cyano in my small tank, feeding habits haven't changed so I'm thinking it's my water.

I have not kept track of how much water I've produced but since setting up my 180 in feb, I'm making between 30-60 gls a week, depending on water change schedule.

Regardless what your TDS is, if you are using this filter system for drinking purposes it is best to at least change it out every six months. Just to be cuatious, the bateria build up on the filters are eliminated this way. If you like the taste of the bateria then just follow your TDS readings.

Our fridge filters water and that's what we use for drinking water.

Coralgurl
12-21-2012, 06:26 AM
Changed out the carbon and RO, but didn't grab the prefilter. I'm running the unit anyway to flush the RO membrane, already tds dropped to 3 within minutes. Will grab the prefilter hopefully tomorrow.

Will not let it get this high again.:redface:

gregzz4
12-21-2012, 08:24 AM
Changed out the carbon and RO, but didn't grab the prefilter. I'm running the unit anyway to flush the RO membrane, already tds dropped to 3 within minutes. Will grab the prefilter hopefully tomorrow.

Will not let it get this high again.:redface:
Little confused ...
When my RO water started to smell of chlorine, I immediately changed both my filters ... pre-filter and carbon filter
I saw no change in my chlorine smell after new filters ...

I was trying to finish my post before it got wiped out :smile:

You can get up to 6 months out of a carbon filter, and 3 years from a RO filter

It all depends on your usage ....

gregzz4
12-21-2012, 09:14 AM
So, here's what I've learned ....

You get 3 months out of of your pre-filter, 3 months from your next stage, 6 months out of your carbon filter, and 1-3 years out of your RO membrane (depending who you talk to)

Good thing lots of members give us lots of information so we can gauge our filters ....

When your RO filter turns brown, you should change it;
When pre-filter turns brown, it's time to change it
When a Carbon filter turns black, it's well over-due
C'mon, don't ask when an RO membrane is past due ....

gregzz4
12-21-2012, 09:44 AM
Changed out the carbon and RO, but didn't grab the prefilter. I'm running the unit anyway to flush the RO membrane, already tds dropped to 3 within minutes. Will grab the prefilter hopefully tomorrow.

Will not let it get this high again.:redface:
Good thing you didn't check the manual ...
TDS for Coralgirl's water must be 000 ...

Good luck with your next reading ...

gregzz4
12-21-2012, 09:46 AM
Gotta tell ya ...

I know you tell us about your crappy Boss ...

Mines a dick too :twised:

gregzz4
12-21-2012, 10:11 AM
Sheena, Coralgirl .....
Look back through a few posts as we have been goobers ....

There's lots of good info there to read ...

Aquattro
12-21-2012, 01:30 PM
Most important is making sure you back flush your membrane weekly. My last one got neglected and when I opened the membrane, it was full of crud. Just disgusting!
Without flushing, you seriously reduce useability and lifespan.

Coralgurl
12-21-2012, 02:21 PM
Did I miss something here??

Bottom line, my filters were dirty, I've been running it for about a year and hadn't changed anything out. My bad! Now I know when to change out and will be more diligent. The RO membrane probably didn't need to be changed but I did anyway, it still looked in good shape.

Aquattro
12-21-2012, 02:23 PM
Did I miss something here??

.


Just Greg talking to himself -lol

KevinK
12-21-2012, 02:40 PM
Most important is making sure you back flush your membrane weekly. My last one got neglected and when I opened the membrane, it was full of crud. Just disgusting!
Without flushing, you seriously reduce useability and lifespan.

I have never dun a back flush, how do you do that even ?

I have a aquasavecanada.com unit

Aquattro
12-21-2012, 04:15 PM
I have never dun a back flush, how do you do that even ?

I have a aquasavecanada.com unit

My unit has a bypass valve for flushing. I flushed my old membrane about every blue moon. Japarto was laughing at me when I complained about lack of output. So he gave me a new membrane, I took the old one out and opened it. Just disgusting. Most of it was plugged with brown sludge. The new membrane gives me about 40% more output now, and I flush it once a week, minimum. I should have taken a pic of it...:)

KevinK
12-21-2012, 04:43 PM
My unit has a bypass valve for flushing. I flushed my old membrane about every blue moon. Japarto was laughing at me when I complained about lack of output. So he gave me a new membrane, I took the old one out and opened it. Just disgusting. Most of it was plugged with brown sludge. The new membrane gives me about 40% more output now, and I flush it once a week, minimum. I should have taken a pic of it...:)

I send aquasave a mail, as I never did it, and I hear it a fair bid that manny do it,

I do have the booster pump, but than again, that might gust press the sludge even more in it.

at this time I dont have a valve, so I might have to put one in, we se

Aquattro
12-21-2012, 04:55 PM
Kevin, from their site...

http://www.aquasafecanada.com/support/installation/aquarium-ii/

Rice Reef
12-21-2012, 06:27 PM
My unit has a bypass valve for flushing. I flushed my old membrane about every blue moon. Japarto was laughing at me when I complained about lack of output. So he gave me a new membrane, I took the old one out and opened it. Just disgusting. Most of it was plugged with brown sludge. The new membrane gives me about 40% more output now, and I flush it once a week, minimum. I should have taken a pic of it...:)

I heard from Japarto... Enough to convince me to upgrade my unit to the vertex deluxe model... It flushes automatically at start and every two hrs and a bit...

I send aquasave a mail, as I never did it, and I hear it a fair bid that manny do it,

I do have the booster pump, but than again, that might gust press the sludge even more in it.

at this time I dont have a valve, so I might have to put one in, we se

Kevin, I have a spare back flushing valve available now that I've upgraded...

mike31154
12-21-2012, 07:40 PM
When I see the term 'back flush', there is potential for confusion, for me anyhow. To me, back flush means sending water back through a system in the opposite direction which isn't how the combination restrictor/flush valves used on most RO systems work. What happens during flushing is that the flow restriction is removed downstream of the RO membrane housing allowing all the source water to bypass over the outside of the membrane. That is, no water is forced thru the membrane walls, but the water is still traveling the same direction. This should help flush any accumulated sludge from the outside of the membrane to the drain. To me, 'back flushing' would mean hooking a water source to the output/drain of the system and forcing it 'backwards'. If one were to do this, all the crud & sludge in the RO housing would be sent back to the carbon & pre filter stages. May be a nit pick, but it helps avoid confusing goofs like me.

I open the flush lever on my flow restrictor for a few minutes before & after every production run. My RO membrane is still producing TDS 1 from a source of 210+ after 3 years 8 months and an estimated 17,000 gallons of throughput. I track throughput on Excel spreadsheet & it is based on RO and DI water produced, plus the estimated waste water using a 1 to 4 product to waste ratio. The original 0.5 micron carbon filter was rated to effectively reduce chlorine taste & odor through 20,000 gallons @ 1 GPM. We don't come close to running 1 GPM through our systems. Although I finally changed that out in July after 3 years of production, it probably could have stayed in longer, although at my estimate of 17,000 gals thru, it was getting close to rated capacity anyhow. My DI media was exhausted so I simply changed the carbon at the same time, more for convenience than anything else. Last time I checked the water for chlorine after the carbon block was some time ago, but it still showed 0. Not all carbon blocks are created equal though, so check the capacity of yours before trying to run it as long as I have & get a swimming pool test kit with chlorine strips included to confirm it's still good or not.

No way I'm going to toss a high quality carbon block on a calendar based schedule like 6 months if I have no idea how much water has gone through it. Sure it's only about $20 for a new one, but it's still a waste if the thing can run for 2 more years at the amount of water I produce. With respect to bacteria, if you run your system at least once a week, I reckon the danger of bacteria multiplying in the standing water in your RO system is relatively low. The water in your pre filter housings will still have chlorine or chloramine in it & the system is totally sealed. Once you turn the system back on & flush it for a few minutes as you ought to, anything bad is going straight to the drain. After applying the restriction to produce water again, it should be all good. I've been using RO water for drinking, making beer, wine etc for years and no issues with bacteria so far. I've never disassembled my unit & disinfected it since starting production over 3 years ago. Change the pre filters when they start turning a tan colour and/or the pressure differential on my gauges increases by several psi.

KevinK
12-22-2012, 03:15 PM
Kind of what you ar saying is that back flushing is nothing more than allowing the full amount of water go in and out of the housing.

This in turn would mean that in my case I have to gust cut the line (out) directly behind the housing of the RO and put a T in with on one side a little tap

Open this new installed tap, and it flushes ( bypassing the DI, and the flow restrict or)

Wayne, in this case I might drop you a line after x mass ( than you can maybe also give me some pointers for using my camera taking close up)

mike31154
12-22-2012, 04:03 PM
Kind of what you ar saying is that back flushing is nothing more than allowing the full amount of water go in and out of the housing.

This in turn would mean that in my case I have to gust cut the line (out) directly behind the housing of the RO and put a T in with on one side a little tap

Open this new installed tap, and it flushes ( bypassing the DI, and the flow restrict or)

That's it in a nutshell, yes. Nice way to put it rather than the novel I wrote & a very good idea/solution if you don't have the combination restrictor/bypass valve. But to reiterate, it's not considered 'back flushiing'. Lose the word 'back'.

EDIT: One more thing worth mentioning with regard to flushing. Keep in mind that as long as your system is running, including flushing, your carbon block is still stripping chlorine from the water. This is one reason I'm not that keen on the automatic flush systems that flush for a few minutes every hour or so while the system is running. It means you're using up carbon & sending more water down the waste line. You have to weigh the pros & cons, do the math. More waste water vs a 'possibly' cleaner RO housing. Manual flushing for a minute or two before & after each run seems to work well for me, but then again, I haven't opened my membrane housing because the membrane is still good after 3 years & production hasn't dropped significantly.

reefgirl189
12-22-2012, 04:22 PM
Very glad to have read through this thread. We are running off of a new well water source here and need to change filters twice as often as the average person. TDS still reads 0 with proper care and attention to the RO/DI system.

gregzz4
12-22-2012, 07:52 PM
Just Greg talking to himself -lol
A little cross-thread confusion on my part
Too much End of the World party :surprise: