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5 Year Old RO/Di Filters - Still good?

The membrane is the more expensive part but is also the longest lasting.
I’d replace the sediment, carbon first and check TDS; if you run a DI canister, unplug it to check the TDS and the water production rate. My guess is if the membrane is good, you should have a good flow and very low TDS which the DI would take care of.

The flow out of the unit was actually very good, which surprised me to say the least. The gauge read 60PSI which is decent for being on the top of the hill in Russian Hill. There is a chance that the membrane is shot but the 2x DI resin cartridges are working their butts off and I will see some TDS creep. Perhaps that's why it is reading 0 TDS at the point in time.

Either way, if the existing filters produced 0 TDS water, and I'm not drinking it, I think I might give it a shot...At the very least I could change out of the carbon block with a chloramine carbon block.
 
Most of the rodi isn't worth anything. It's the cartridges that cost there money.

I bought like a case of everything when brs had black Friday sale for this reason. It'll lasts me for years. I change my cartridges once a year. Except the membranes.


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Most of the rodi isn't worth anything. It's the cartridges that cost there money.

I bought like a case of everything when brs had black Friday sale for this reason. It'll lasts me for years. I change my cartridges once a year. Except the membranes.


Sent from my iPhone using Tapatalk Pro
Seems like you'd go through more water with such a large tank. Are you part of the no water change crew
 
If the DI media is getting depleted fast, that’s a big hint something’s not right; a clogged membrane produces very little water, you’d see the rejected product being way much more than the clean water. Start with new sediment and carbon then check TDS without the DI connected.
 
If the DI media is getting depleted fast, that’s a big hint something’s not right; a clogged membrane produces very little water, you’d see the rejected product being way much more than the clean water. Start with new sediment and carbon then check TDS without the DI connected.

Thanks and I will let you know once the new filters arrive, but I don't have an aquarium to fill quite yet, still working on that one.

-Mark
 
You’ve mentioned not drinking the water a couple times and that seemed a little odd to me. The water I use for my tank (before I add salt) is much cleaner than what I would be fine with drinking.
 
You’ve mentioned not drinking the water a couple times and that seemed a little odd to me. The water I use for my tank (before I add salt) is much cleaner than what I would be fine with drinking.

Not sure why that sounds odd? This is going to be purely water made for the tank, so it wouldn't impact human life. Where's the disconnect? Additionally, while the water you use is technically "cleaner" or "more pure" than your typical drinking water, DI water is generally not recommended for drinking as the cartridges are not NSF. So, back to my last few comments, since I'm not drinking this, I'm willing to take a risk and see if these original, 5 year old filters hold up.

Thanks again to everyone who's contributed!

-Mark
 
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I tee off mine before the membrane for drinking.

Before the membrane or directly after? When I had my previous RO/DI set up I had a drinking water attachment with bladder tank storage and Tee'd mine off after the membrane so that I had RO filtered water, but not DI water.
 
I did mine Befor membrane as I dont have the air bladder storage tank, nor a tap, nor a hole in my counter for a tap. This way I get sediment and chlorine/chloramine/lead removal at a reasonable rate.
 
Not sure why that sounds odd? This is going to be purely water made for the tank, so it wouldn't impact human life. Where's the disconnect? Additionally, while the water you use is technically "cleaner" or "more pure" than your typical drinking water, DI water is generally not recommended for drinking as the cartridges are not NSF. So, back to my last few comments, since I'm not drinking this, I'm willing to take a risk and see if these original, 5 year old filters hold up.

Thanks again to everyone who's contributed!

-Mark
I misunderstood you then. When you were saying it wouldn’t be used for drinking water I thought that you were implying that it wouldn’t matter if some impurities were present since you weren’t drinking it.
 
Interesting results today on the original cartridges (Build Date: 2012):

Using the HM Digital AP-1:

10 minutes run time: 0ppm TDS
60 minutes run time: 0ppm TDS
120 minutes run time: 0ppm TDS

Approximate GPD @ 60PSI = 55 (Quoted at 90GPD @ 60 PSI, however, it is using a FilmTec 98% rejection membrane stated at 75GPD on a 90GPD system?)

Approximate Waste Water GPD @ 60 PSI = 180

Ancillary Info:
- 70ppm Input --> 84ppm Output (waste water) ~ 20% Delta
- 70ppm Input --> 4ppm Output (filtered water) ~ 94.2% Rejection Rate


Would it be safe to say that everything is in good, usable condition? I would say for an input of 60PSI, the system is under producing but I always have had my RO/DI systems under produce the marketed numbers...
 
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If I read it correct, that's a lot of waste water but the unit still doing its job @ 0 TDS
Maybe the former user went for a lower GPD membrane to save a few bucks.
Question, Is the TDS at 0 with or without the DI media?
 
If I read it correct, that's a lot of waste water but the unit still doing its job @ 0 TDS
Maybe the former user went for a lower GPD membrane to save a few bucks.
Question, Is the TDS at 0 with or without the DI media?

The FilmTec 75GPD membrane actually came from SpectraPure for the 90GPD system. No idea how that math works out, but I'm guessing it has something to do with pressure as it is stated to operate at 90GPD @ 60PSI...

The TDS is 4ppm coming from the sediment, carbon block and membrane. The TDS out of the 2x stage DI is 0ppm.
 
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Seems good to go to me.

I think flow restrictors have to match the membrane rating; I wonder why would Spectrapure would stuff a 75 membrane in a 90 rated and marketed unit. I don’t know much about technicalities on RO units but seems a bit odd. I’m aware PSI at the tap and trough the filtering unit has to be at X-numbers for the product and waste to be within the rating of the units; also important into the production of pure water is the temperature from the tap.
 
That rejection rate is normal. I'd put a booster pump and a second membrane in line.

Booster pump and second membrane will definitely improve the product/waste ratio for sure but as I read his post, I think 55g of usable water vs 180g of approximately waste water is a bit high for a unit that’s rated at 2:1 ratio; I think the membrane, although is doing a good job on filtering the water, might be rejecting more, could be an indication that is getting a bit clogged.
 
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