DI add on

[Indermark]

First off heres my question, I tested the TDS coming from the RO membrane its coming out at 50PPM. after the DI its coming out 25-30PPM. My unit will be a year old in December and I did the 6month change on the sediment filter and carbon block a little late but when I first set up the unit I was using it for my 12 gallon tank so not much water was being produced than. I have that is from another sponsor on RC (PH2O) and want to add a double DI or maybe a single I think the DI that I have now only holds about a cup of DI resin. Whats your suggestions?

thanks,

Ryan

[BuckeyeFS]

First, let's make sure that your readings are accurate. Please use your tds meter to sample first, your DI water; next your RO, and finally your tap water. Use a sqweeky clean glass right out of the dishwasher to take samples. Let the system run for 10 minutes before taking your samples. Rinse the drinking glass out several times with the water you are going to measure, before taking each sample. Let me know wat the three readings are and we'll go from there.

Is the DI resin housing you have now vertical or horizontal?

Russ

[Indermark]

horizontal (inline). I did what you stated accept wait 10minutes. I will do it again tonight after school. I used a tea cup that I rinsed with RO water.

[Indermark]

okay I let the system run an hour, i forgot to go check after 10minutes. Hope that doesn't influence the results any. I did everything you said and did get different results. okay so product water TDS tested at 29PPM. the water coming out of the RO membrane tested at 29PPM as well. My tap is water is 390PPM.

[BuckeyeFS]

So your membrane shows a 93% rejection - good for a 100 gpd membrane, not so good for a 50, 75, or 150 gpd membrane (which should give you 96 to 98%).

You're resin is shot (and has been for some time) and needs to be replaced. At a minimum, replace the resin and orient the DI housing vertically with bottom up flow. With your high tap water tds you'll probably want to get rid of that undersized DI in favor of a refillable, full sized, vertical DI cartridge - if you want to do that either we can walk you through replumbing the system you have to turn your second carbon stage into a DI stage (this requires some disassembly and reassembly of your system, or you can leave the system configured as it is and add a BFS-72 Add on DI kit.

Russ

[dbfishnut]

Spectrapure shill post removed...

[Indermark]

<a href=showthread.php?s=&postid=11140321#post11140321 target=_blank>Originally posted</a> by BuckeyeFS
So your membrane shows a 93% rejection - good for a 100 gpd membrane, not so good for a 50, 75, or 150 gpd membrane (which should give you 96 to 98%).

You're resin is shot (and has been for some time) and needs to be replaced. At a minimum, replace the resin and orient the DI housing vertically with bottom up flow. With your high tap water tds you'll probably want to get rid of that undersized DI in favor of a refillable, full sized, vertical DI cartridge - if you want to do that either we can walk you through replumbing the system you have to turn your second carbon stage into a DI stage (this requires some disassembly and reassembly of your system, or you can leave the system configured as it is and add a BFS-72 Add on DI kit.

Russ

My unit does 75GPD. I think I will add the BFS-267. I just have to see If I have room for it. Does exhausted DI throw back TDS sorta like charcoal would leach back everything its absorbed? I just want to know If I should just take off the DI unit and hook it straight to the RO, until I get in the new DI. How do you think the RO is performing. I am just wondering because the unit I have goes through one sediment filter than a Carbon Block (both purchased from BFS) then it goes to the RO and then DI. Do you think I would be better off running the BFS-267? than the BFS-72?

Thanks,

Ryan

[BuckeyeFS]

<a href=showthread.php?s=&postid=11140962#post11140962 target=_blank>Originally posted</a> by dbfishnut
Hey BFS,
I was told by filmtec that your statement about the higher the gpd the membrane is rated for, the less pure the water is, it not true. The lady I spoke with said that many years ago that was true, but the technology & material used has changed. It does not matter what size you get, they should all do between 95%-98% rejection and if it is below 95% to change out the membrane.

The TW-1812-24, 36, 50, and 75 gpd Filmtec membranes have a minimum salt rejection of 96%, and a stabilized salt rejection of 98%.

The Filmtec 100 gpd has a minimum salt rejection of 90%, and a stabilized salt rejection of 90%. If you email us we'll be happy to email you the Filmtec documentation.

Not sure what to tell you re the information to the contrary provided to you. I'd be happy to learn I'm mis-informed here, but I don't think that's the case.

Russ

[BuckeyeFS]

My unit does 75GPD. I think I will add the BFS-267. I just have to see If I have room for it. Does exhausted DI throw back TDS sorta like charcoal would leach back everything its absorbed? I just want to know If I should just take off the DI unit and hook it straight to the RO, until I get in the new DI. How do you think the RO is performing. I am just wondering because the unit I have goes through one sediment filter than a Carbon Block (both purchased from BFS) then it goes to the RO and then DI. Do you think I would be better off running the BFS-267? than the BFS-72?

Yes - the exhausted DI resin will dump tds back into the water. You are better off without it for the moment.

93% isn't good for a 75 gpd membrane. We know that you've gone to the trouble to take accurate tds readings, so the 93% should be accurate. Its a trade off situation for you now - Invest in a new membrane and get higher rejection that will lead to extended DI life; or save some money now by not buying the membrane and spend it instead on DI resin.

Your tap water tds is pretty high (390 ppm) so I would lean towards replacing the membrane sooner rather than later.
If you went from a 93% to a 97% rejection, the usable life span of your resin would more than double.

Having a double DI wouldn't make the resin last any longer, but it would assure that if you forgot to change your resin you'd have that second DI cart in place as insurance. It would also assure you that if the first DI cart missed something, the second would remove it.

Russ

[Indermark]

Great...Well I just might as well buy a new RO/DI system It would just cost me an extra 80 or so dollars. Any suggestions? I have an RO flush kit as well as a float valve. I have not hooked up the float valve yet. Is there any way I could hook up my old to the new to produce less waste water and or but less work on the RO membrane?

Ryan

[BuckeyeFS]

Not really. There is a misunderstanding amoungst reefers that membranes plumbed in series reduce waste water - that's only true in cases with unusually low feed water tds. Our Premium Series systems are our best sellers.

[Indermark]

I need to start proof reading before I post. I'll have to take a look at what BFS is offering. I just don't see the point in replacing the RO membrane to a system buying a DI add on for a system that is not even a year old. Thanks, for your help I do have additional questions but will ask later if I do not answer them myself.

Ryan

[Indermark]

I went ahead and ordered a new RO/DI unti early this morning around one. Can't wait to set it up and start getting some pure water. I'm sturggling with bubble algae right now, I hope the source water is the cause of it. I just installed a new sediment filter as well as a new carbon block that I purhased in September can I just use them for another 4 months and replace them with the new ones that come with the BFS unit? OR I was going to hookup the old unit to the new to get some use out of the RO membrane and filters I currently have in it, I think its a good idea any thoughts?

Ryan

[BuckeyeFS]

Ryan - as long as the prefilters you have are not clogged, and as long as you don't exceed the chlorine capacity of the carbon block, and as long as you don't have any biofouling issues in your existing system, it is safe to move your existing prefilters to the new unit, and save the new prefilters for your next change.

What are the pore sizes on your existing sediment filter and carbon block?

Russ

[Indermark]

1 micron sediment cartridge and the chlorine guzzler

[BuckeyeFS]

Same as what came in your new unit.

Russ

[Indermark]

I wanted to thank you for your help when I called the other day. I really like the new unit. I decided to hook up my old sediment filter and Carbon block as a prefilter, I guess you could call it that. With it hooked up to my new filter I get RO @ 8 PPM TDS. and of course zero PPM TDS after the DI. I cannot remember the exact number of the RO TDS but before I added the old to the new but it was coming out between 10-14 PPM TDS from what I remeber. What color will the resin change when exhausted. I also opened up my old RO membrane just to see what was going on inside. To my suprise there was not a Dow Film Tec RO membrane inside. It was a no name I just remember it had TFC on the side of it. It looked nothing like the DOW membrane besides the fact they were both blue. I thought the unit would have once since thats the only RO membranse they have for sale at the site.

Thanks again,

Ryan

[BuckeyeFS]

Ryan - Those retrofittted drinking water systems can be like a box of choclates...

The resin in your new system will go from a very dark purple to a tan - its very obvious - you'll see it from across the room. The color change should start at the bottom and move up.

Don't relay on the color change alone as the indicator of when the resin needs to be replaced - use it as an indicator that you need to break out your tds meter a bit more often and keep an eye on the tds of the DI water.

Russ