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Reverse osmosis (ro) systems

I have been using distilled water so far for my plants, but am planning to switch to RO to save money (in the long run). I have read previous articles on these forums, and have narrowed it down to these two systems:

AQUA AQUARIUM 100GPD REVERSE OSMOSIS WATER FILTER

Reef 125GPD Reverse Osmosis Water Filter +DI+free 5 rpl

Which one do you think is better?  Basically I am looking for something in the $60-$100 price range.  If you have any other suggestions, I would be glad to hear them.

Thanks,
Ben
 
They are essentially the same. Either would produce water much purer than you need. You can save money in the future by removing and not replacing the post RO membrane carbon and DI filters..

The key elements are a good prefilter for sediment and then a carbon block. That keeps your RO membrane safe from chlorine and sediment that can clog it. The RO membrane will remove about 98% of water contaminants which is plenty fine for any cps.

Tony
 
Thanks for the reply Tony. If they are pretty much the same, then it seems like the bottom one is the best deal since it has a free replacement set of filters and some other extras.

I remember you said in another thread that it is important to have standard size filters. How can I tell if that is true of these ones?

Also, the bottom guy is selling a TDM meter for $23. I read in other threads that these need to be kept wet, but this one does not seem to say that?

-Ben
 
Not sure about which system is best, but I bought from the upper vendor and found him reputable and helpful, and I love my R/O system, which is similar to the one you're looking at.

Capslock
 
If you look at the units you will see the 3 vertical canisters underneath. These are the standard 2.5 x 10" filter housings. These house the prefilters. Both units have 3, so you have more than enough.

Portable tds meters don't need to be kept wet. They have a couple metal probes on the bottom. They are quite durable but it is important to periodicially check the calibration with calibration solution.

T
 
I bought this one RO System
This one comes with a tank, the one you linked to doesn't have a tank. Works for me, except the auto shutoff doesn't work, it may be because my water pressure isn't high enough.
 
Oooh, good point, get one with a tank! Makes filling jugs of water much easier. In fact, I bought two tanks and just "wired" them in parallel, and now I have lots of water on tap whenever I need it.

Capslock
 
Thanks for the info. I was leaning toward the other one at first, but now I notice that the Aqua-Safe guy seems to have a much better warranty and reputation. Plus he lives in my state, so I suppose it couldn't hurt to support local business
smile.gif
.

I am thinking I will try the one with the tank, and add in a TDS. I remember Tony saying in a previous thread that the tanks cause more waste water. Have you guys noticed this much? What do you do with the wastewater? Can it be added to another tank?

I am mostly planning on using this for an ultrasonic humidifier and about 12 plants, so I would probably use about 1-2 gallons a day at most.

-Ben
 
Hmm. I'm not aware of it using more wastewater. The wastewater in an RO unit is water that is washing the RO membrane as it builds up with minerals and impurities. You don't want to use this water on your cps. But you certainly could save it for other uses. Mine just drains into my basement utility sink, though in a drought year I'd probably save it for watering my regular plants.

Capslock
 
  • #10
Why would a tank waste more water? I've never heard of that. All a tank does is keep water at hand, provided the unit has an auto shutoff device. If you want a large volume of water, buy a float valve, I have a constant supply of 32 gallons at hand whenever I need it. THe 90GPD unit I have easily refills it overnight (empty), or within an hour if i take out a little water for use.
 
  • #11
I heard about the pressure the tank creates wasting more water in this thread, second post down.  I am not too worried about it, I was just wondering how big a difference it causes. I suppose if I wanted to use the "waste" water, I would need to get another tank/container to store it in.

Also, do you know if adding a UV filter would help a lot in removing viruses and bacteria, or does this setup do that the way it is?

Thanks,
Ben
 
  • #12
I don't see how a tank system with a shutoff valve could possibly waste more water. My RO unit shuts off as soon as pressure is reached.

IMO, UV filters are a waste of money unless your source water is known to have biological contaminants.

Sam
 
  • #13
The tank may cause more wastewater. Since the tank is pressurized, the system has to work harder to fill the tank. And water will flow to where there is less resistence, the wastewater tube. That's my theory. I collect the wastewater in a bucket and dump it when it's full. I sometimes use the water on non CPs. I tested the wastewater's ppm, it has more TDS than tapwater
smile_h_32.gif
If you're concerned about it producing too much wastewater, put a flow restrictor on the wastewater line. You'll need to give the membrane a good flush once a month or too much bad stuff will be collecting on it.
 
  • #14
I'm not overly concerned with wastewater at this point, since I will probably only use 1-2 gallons of water a day. I just would like to optimize it without bringing in other problems.

If the source water does contain bacteria/other biological contaminants, does this mean that a UV filter is required to remove them? Or will the RO filter them out? I imagine there must be some advantage to UV since all the water dispensers I see at stores claim to use UV. How can I even know if the source water contains biological contaminants?

I found what seems to be a relatively cheap UV filter here:
http://cgi.ebay.com/ws....hosting

I am not planning on getting one now, but I was just thinking about it as a future possibility. Especially if I want to use the water for things other than just plants. I don't know how much plants are affected by bacteria in water.

By the way, this is the system I ended up getting, after seeing so many recommendations:
http://cgi.ebay.com/ws....1819204

I'll try to remember to post the outcome once the filter arrives.

-Ben
 
  • #15
Ben, If the RO filter can remove disolved mineral molecules, then bacteria will be removed too. Pushing a bacterial cell through the membrane would be like trying to drive an eighteen wheeler through a 12" diameter culvert. It ain't gonna happen unless the membrane is bad. The only reasons I can think of for needing a UV stage would be 1) Back up in case the membrane goes bad and 2) messing up viruses. Some of which are small enough to get through an RO membrane and UV does a number on the DNA. If a person is on a well they might want a UV/RO unit for that reason. As for why the store units have them, I suspect it has more to do with the idea that UV treated water is more sanitary than just plain RO water.
 
  • #16
Ben, UV filters are on grocery store water dispensers for two reasons that I can think of:

1- Marketing-you feel like they care about your well-being and you buy more from them.

2- CYA-Just in case there are biological contaminants that get through, they want to cover their booties to make sure it wasn't their water that got their shopper sick.

Otherwise, if you're on a well and you know your water has, say, coloforms or other germs, it'd be a good reason to put in a UV filter. Your local water company should have a yearly report that you can check out that will have all of the statistics for your local water concerning solids, contaminants and biological contaminants. Most even have websites where you can DL the materials-mine does.

Sam
 
  • #17
Thanks, I'll look into that.

-Ben
 
  • #18
I am expecting to receive the RO filter tomorrow, and I have a couple quick questions:

1.This system has a final granular activated carbon filter "for taste" that the manual says may release carbon dust into the water. Is this harmful to the plants? Should I remove it?

2. Does anybody have enough experience with these eBay systems to know if they are safe to drink from? I am kind of wary about drinking water from a filter off eBay and would like to know if there is a big risk in case I ever want to use any water for stuff other than plants.

Thanks,
Ben
 
  • #19
Sorry for posting again, but I just received the RO filter from Aqua-Safe Systems. Using the TDS meter, I determined that my tap water has a TDS of 31 at worst, and low 20s at best!! Apparently the water company wasn't exaggerating about having high quality water. I thought it would be a lot worse because of the white buildups I have seen after water evaporates.

I installed the filter since I still need a way to remove the chlorine and other chemicals. My water pressure is also quite good at 70PSI. After the RO membrane, the water had a PPM of 2. After the DI stage, the PPM was 0, the same I get with my distilled water. Unfortunately the final carbon filter brings it up to the low 20's again. I was told that this should go down after it has been in use for a while. Hopefully it doesn't affect the plants.

With such high quality water, will the filters last longer than the usual 6 months, or will chlorine still require them to be replaced just as much?

In any case, I plant to test the affects of pure tapwater on some extra plants to see if they can handle it, since it gets such a good reading.

-Ben
 
  • #20
It is imperative that you replace the carbon Prefilter on a regular basis, depending how much total water you put through the system. This is the filter that is removing the chlorine. If the carbon prefilter stops removing the chlorine it will get through to the RO membrane and punch big holes in it. This will allow sodium, calcium and all sorts of other mineral molecules to pass through into the water your collecting. Or in your case into the Post DI cartridge. Which will get very expensive to keep replacing.. or you will not replace it and your water will not be as high quality any more. Which is why a TDS meter is nice with an RO system because the membranes are usually only good for a few years roughly and need replacing sooner or later. The TDS meter will allow you to keep an eye on how well the RO membrane is working.

Sounds like your post carbon filter is leaching some minerals.. not an uncommon thing. I would just remove it and toss it..A post carbon filter after RO/DI to improve taste is baloney. Water that pure (ro/di) will taste flat but that's because it has no minerals in it! With the post carbon filter leaching some minerals, it adds a little life to your taste buds.

Yes you can drink the pure ro/di water.
 
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