RO/DI TDS WDYT??

[caferacermike]

I finally have my new/used 6 satge ROunit running. YAY! Ok so I bought this thing used about 4 months ago here at MAAST. I bought all new filters and hoses. I have 3 sediment traps( 1 5micron filter, 2 carbon 5 micron filters), 1 RO membrane for 100GPD, 1 more carbon chlorine remover, 1 DI unit full of resin. I do have the ability to add a second DI unit as I have another brand new one.

1/4" control valve located before sediment traps. From there it runs throught he sediment traps to the RO membrane. I have the "in" tapped after teh RO. Next it runs through the carbon block and through the DI. From the DI the water goes to my collection jugs. I have the "out" tapped just after the DI.

Right now I'm seeing 180ppm going in the RO and 23ppm coming out of the DI. I thought I should be reading 0ppm? I have awesome pressure as I live near the water pump houses. Im getting a hella stream from the discharge and a trickle from the "clean" water. I did check to make sure the adjuster was still located in the RO unit.

Did a "taste" test and the water coming out of the clean side tastes so much better than the city water.

It's been running for 20 minutes. Is it reef ready?

[hobogato]

you may want to check the water coming out of the RO membrane - it should have a TDS around 25 (assuming a 90% rejection rate). you should be getting 0 TDS after DI. if the membrane wasnt kept wet at all times, it may have dried out and that ruins them.

[caferacermike]

Hhhmmmm...... The RO was shipped dry but nicely packaged in a sealed bag. I'm reading 180 or so after the RO and 20-25 after the DI.

I hope I did not buy a bunch of crap. I got the filter kit from Ebay.

[hobogato]

if the TDS going in and coming out of the RO membrane is the same, then it is shot. if it was used, and then package dry, that is probably why. if it were new, it had a food grade preservative to keep it from deteriorating(sp?) before it was used. once it is used, the preservative washes off and it must be kept wet from then on.

[GaryP]

Sounds like you don't have an RO/DI, just a DI.

[Instar]

To start with you should be using a high quality filter set. A single 1 micron fibre sediment filter followed by 2 carbon blocks that are 0.5 micron particle size carbon blocks and then into the RO membrane. If you get that high a TDS through the membrane, chlorine got to it most likely from expired carbon blocks (used too long or of the drinking water local lumber yard quality carbon blocks used before you got it.). You may have to order these high quality filter sets. Last time I checked locally dealers had stopped carrying them. Lower quality blocks such as 5 and 10 micron carbon blocks are NOT what you want. But, it really doesn't matter with your unit, that membrane is not any good and that means your DI cartridge is going to be used up very fast. You should have less than 20 out of the membrane if it is a good high quality membrane and 0 or near that after the DI.

[caferacermike]

OK swapped my meter around. 154 going into the RO and 38 coming out. Put it back in line to measure input of RO and ouput of DI and I'm getting 154 in 22 out.

These are all brand new filters. I really hate ever saying I bought something used because that seems to imply that everything is used. I stated that every filter is new.

I did make a mistake in that the second sediment is a 1 micron unit.

This is exactly what I have.
http://cgi.ebay.com/New-Reef-6st-100GPD-Reverse-Osmosis-RO-DI-Water-Filters_W0QQitemZ120044151752QQihZ002QQcategoryZ20 684QQrdZ1QQcmdZViewItem

Only difference was that the unit was used for 3 years. The owner recommended I buy the filter set from this seller. So I replaced everything. I did get a new dual TDS meter for it from Marine Depot. This one.
http://cgi.ebay.com/DM-1-Inline-Dual-TDS-Water-Filter-Tester-Meter-RO-DI_W0QQitemZ280040740416QQihZ018QQcategoryZ117435Q QrdZ1QQcmdZViewItem

Oh do and I wish I only paid $18 for it.

So this water is no good for my tank? I have to start all over again? If so it's going straight into the garbage.

[GaryP]

No, you can go ahead and use it.

What we are saying is that your RO membrane is not performing properly. You are only getting 75% removal from the membrane. It should be higher then that. You're going to exhaust your DI resin very quickly with that kind of throughput. I'm not sure why your DI resin is only removing 19 ppm as well. It should be higher, so there is some question there as well. For whatever reason, its not performing like it should.

[caferacermike]

For whatever reason, its not performing like it should.

Exactly and that's why I'm already sick of it. I'm in so far for $200 on this thing and it doesn't work. It's just been to trying for me. I swore off ever getting my own unit and just preferred buying my own. Not like I tested that water but it put my mind at ease. I said to myself $4-500 for a proper RO unit, Hmm.. that sure is a lot of 5 gallon jugs from the lfs.

So it seems my filters I got are cheap Chinese junk. My resin is no good either. Oh well. I just don't see myself spending any more money to "try" and make it work right.

Looks like I will have some nice water to make Kool Aid with.

If anyone else has an idea that maybe something isn't hooked up right or can point me in a complete filter kit for less than $60 I'd like to hear about it.

[Instar]

First of all, you can buy a new RO membrane for a lot less than 400 dollars. Replace all the filters again with the ones I recommended before installing the new membrane unit. If you really can not find a local source for the 1 micron sediment and 0.5 micron carbon blocks, I can give you one on-line. These are not pricey filters, just good ones. Give Richard a call and see if he has them. The unit itself is not bad, it's just a matter of the membrane. That with the correct housing for your unit is not as major a deal as an entire unit. Membranes typically last for 3 to 4 years unless you are very consciencious about taking care of them and changing the filters regularly. Yours has lived out it's life before you bought it, that's all. Till you get this, you can buy a few extra DI cartridges and even though you will burn them quickly, you can use that and the 22 to 38 TDS for mixing water for now. It's just not the target and certainly not the goal since it will burn the DI filter too fast and that will add up in cost enough to justify the new RO membrane cartridge.

This is my editorial perspective and may only be mine and not shared by anyone else, but: Personally I would not recommend that particular system because it is made for drinking water enhancement on your sink and not to purify to the extent we use for reefs as well as the volume we use to make our water changes and top offs. $99.00 is a clue here too. That is basically not a very expensive membrane. It as well as the filter cartridges have similarities to the ones sold at HD for the same thing. I prefer the ones with the clear filter reservoirs because I can easily see what my water is doing to the filters. That mini carbon filter is one of the keys to what this is made for.

[Enigma13]

I do not know why someone else has not clued in to this already, but the water should flow through the carbon block before the RO membrane. Your description above says that the carbon block comes after the membrane. The carbon block is the key to removing chlorine which will toast the RO membrane and the carbon block will also remove some bigger ions like calcium etc. that can clog the membrane. By having it routed so the carbon is after the membrane you really have bypassed the safety mechanisms for the membrane and it is probably toast. Membranes run about $80-100 as mentioned above. Your flow patterns should be as follows sediment, carbon 1, carbon 2, membrane, DI1, DI2.

[hobogato]

Your description above says that the carbon block comes after the membrane. The carbon block is the key to removing chlorine which will toast the RO membrane and the carbon block will also remove some bigger ions like calcium etc. that can clog the membrane. By having it routed so the carbon is after the membrane you really have bypassed the safety mechanisms for the membrane and it is probably toast.

i did not mention this because mike said he had two carbon cartidges before the membrane and the carbon block after. if it were me, i would do what you said and put the carbon block before the membrane as well.


Membranes run about $80-100 as mentioned above.

buckeye field supply has filmtec membranes - 100gpd for around $45.

[Instar]

The description is actually a bit deceiving. I believe the "sediment" filters he refers to are actually 1 (as in single tower used for this) fibre sediment pre-filter at 5 micron mesh size and then the next 2 towers are 2 medium grade carbon blocks of 5 micron particle porosity, then into the RO membrane. The last 2 are the DI and then that little carbon tube thing (referred to as a carbon block) is presumably to capture any last junk if the DI resin is expired or leaches because it wasn't changed soon enough. A useless piece so long as everything is working and maintained correctly.

One question not answered yet: You do not need a second DI cartridge once you are setup and operating correctly.

[caferacermike]

More money more problems.

I'm retiring it to make lime flavored Kool-Aide. I don't have another couple of hundred dollars to "play" with again.

Instar thanks for helping. It's not your answers it's the lack of funds. Oh and when I said $400 I was not referring to a new membrane. I was relaying my feelings about ever getting setup with a new RO unit. As in $400 would buy me years and years worth of 5g fill ups at the lfs at 10 cents a gallon. Since I'm at the shops about twice a week anyways it doesn't matter to me to haul those jugs around. And now that I actually set one up instead of succeding I only wasted my money.

[safeuerwehr]

according to Brian at purity 100gpd membranes have about a 90% rejection rate as compared to a 75 or 50gpd which have a 98-99% rejection rate...so in essence your output out of the membrane will be high and thus eating up your DI resin in no time.....

[BuckeyeHydro]

We do a steady flow of business re working these systems once folks understand just what the bought. This is a little confusing because of some conflicting jargon used above, but best as I can understand:

You have three vertical housings, which contain, in order of water flow: 5 mic sediment filter, `1 micron carbon block, 5 micron carbon block. Then a 100 gpd knock off brand 1oo gpd membrane, then a horizontal DI housing, then a in-line taste and odor (GAC) cartridge.

Your tap water has a tds of 154, your RO lowers that to 38, and your DI lowers that to 22. For sake of discussion let's assume these readings are accurate.

Let's talk about the configuration of the system, and then how your particular system is working.

In general, you want to protect the carbon blocks with your sediment filters. So the final sediment filter (you only have 1) should have a pore size smaller than or about equal to the pore size in the subsequent carbon block. You have a 5 mic sediment filter followed by a 1 micron carbon block. To maximize the performance of your system you'll want to go with a 1 micron sediment filter ahead of a 1 micron carbon block(s), OR go with a 5 micron sediment followed by a 5 micron block(s). Bottom line - use your carbon blocks to adsorb VOC's, not act primarily as sediment filters.

Next, you have a 100 gpd membrane. Unless you can determine the brand name, no telling what to expect from it.

Next you have a relatively small, horizontal DI housing. Horizontal housings for DI resin are a fundamental design flaw. For a short-term fix remove the DI housing from its current position and mount it in a vertical position with the water frlowing from the bottom up. For a better solution get a full size, vertical DI housing with a refillabel cartridge.

Now, assuming your DI resin was operating as it should, you then take water that is as clean as you can make it and run it through GAC. Another fundamental design flaw. Remove the final horizontal in-line GAC cartridge. It is not needed and is counterproductive in the current configuration of your system.

Now, on to the performance of your system:
Your membrane is rejection only about 75 % of the tds in the feed water. Assuming you have adequate pressure, you can do 90%+ with a 100 gpd Filmtec membrane; and 96to 98%+ with a 75 gpd or 50 gpd Filmtec membrane. I recommend you replace the membrane.

You are getting 22 ppm tds water after it comes out of the DI and has passed through the GAC. First, as mentioned above, get rid of the post DI GAC. Run the system again for a few minutes and get a post-DI reading again. It may be near 0. Remember that the post DI GAC will ADD dissolved solids.

Russ @ BFS

[caferacermike]

Thank you Russ. That was the most complete answer I could have ever expected. You took the time to not only read but understand what I wrote. I now understand my system better than ever. You are correct about the GAC filter being last. I had no idea that it can ADD solids. I was impressed by your prices, checked em about 3 days back, IF I decide to give it another try (probably not until after the holidays) I'll bring the entire unit by and get all new cartridges from you.