RO/DI TDS Help

[asmodyus]

Okay so my stage 4 75GPD RO/DI was outputting water at about 04 to 05 TDS out of the prodcut water and membrane. I also only had a 5 micron filter. So I decided to change my filters and add another stage. so I know have a sediment filter, Carbon 5 Micron, Carbon 1 Micron and DI.

Okay so now my TDS dropped to a steady 04 on the TDS meter. So than I went ahead and changed the membrane to a new 100 GPD and now I am getting a 03 TDS on the membrane out and the a 03 on my RO product water. Also I am getting about 400 ML a minute out of my product water after I installed an 800 flow restrictor. So I than thought I might had bad Resin so I got some new Resin and still 03 on the membrane out and 03 on the product water. So know I have now clue what to do next. Also I live in largo.

 

[soeminpaing]

Can you explain more clearly about post RO tds and post RODI tds? If you have post RO 03 tds then it is normal. But If you have post RO of 3 tds and post RODI of also 3 tds then your resin is probably exhausted. Or maybe you don't fit the canister properly when changing new DI resin.

 

[asmodyus]

Can you explain more clearly about post RO tds and post RODI tds? If you have post RO 03 tds then it is normal. But If you have post RO of 3 tds and post RODI of also 3 tds then your resin is probably exhausted. Or maybe you don't fit the canister properly when changing new DI resin.

Correct I have a Post RO of 03 TDS and a Post RODI of also 3 and I just changed the DI resin because I though I might have had a bad batch. But this new batch of resin is till getting Post RODI of 3. I checked the canister there only one way it attaches with the arrow pointing up.

 

[CrazyEyes]

Bad TDS meter ?

 

[asmodyus]

Bad TDS meter ?

Nope I have a hand held TDS meter that has been calibrated and I had the water checked at Coral Corral with there TDS meter. All within the .05 to 01 range.

 

[oldsaint]

Any channeling in the DI canister? Is it a Vertical or Horizontal DI canister?

 

[Bruce51]

low water pressure?

 

[laserjim]

Make sure you didn't put your DI cartridge in upside down.

 

[asmodyus]

Any channeling in the DI canister? Is it a Vertical or Horizontal DI canister?

Not sure what you mean its a vertical canister.

And here is a close up where you can see the arrow is up so its installed right.

 

[asmodyus]

low water pressure?

Pressure is good about 50 at my place

 

[snake1]

Do you pack the di resin as much as you can in the container.

 

[asmodyus]

Do you pack the di resin as much as you can in the container.

Yes I did and I think I am going to order a new container for the DI that the only thing I have not replaced.

 

[Planefanatic]

I know this seems a bit silly to say, but is there any chance you may have put the tds probe on the input of the di resin canister? I know when I rebuilt my system wich is a bit overzealous I goofed. Just check it out before you by new canisters.

 

[snake1]

The picture of the di canister doesn't look like it's packed all the way to the top ....you have to put it in tap it on the ground till it's settles and repeat until it all the way till the top then put the sponge on top and cram the screw top back on even know it's hard to put on ...That's how I put it on

 

[asmodyus]

The picture of the di canister doesn't look like it's packed all the way to the top ....you have to put it in tap it on the ground till it's settles and repeat until it all the way till the top then put the sponge on top and cram the screw top back on even know it's hard to put on ...That's how I put it on

http://www.marinedepot.com/SpectraP...Cartridge-SpectraPure-SP2115-FIRORPDI-vi.html

this is the canister I have. You can see that it has a huge filter in the top so yeah its packed all the way.

 

[ichthyman]

If there isn't a fault in the meter nor a "plumbing" bypass of the DI then it must be current configuration is pulling down as far as the cartridges and resin will allow. Not all cartridges, resin too, are created equally and what you are using maybe performing to spec in your configuration. From experience, I would be suspicious of your choice of not only cartridges and resin but also the membrane. Start by looking up the manufacturer, not reseller's advertisement, specs for each component.

I'll give you one hint, 100 gpd membranes typically have much lower rejection rate than their 75 gpd counterparts. IIRC, @50 psi ~90% vs ~97+%. Yes, they make more water but at a cost. A microfiltration membrane would be a better name.

 

[asmodyus]

I'll give you one hint, 100 gpd membranes typically have much lower rejection rate than their 75 gpd counterparts. IIRC, @50 psi ~90% vs ~97+%. Yes, they make more water but at a cost. A microfiltration membrane would be a better name.

Correct its a DOW FILMTECâ„¢ TW30-1812-100 Applied Pressure psig (bar) 50 (3.4) Permeate Flow Rate gpd (l/h) 100(16) Stabilized Salt Rejection 90 (%)

Also from what I am reading it needs a 5 to 1 ratio to operate and I am barley getting 4 to 1 ratio and I am using a 800 Flow restrictor for a 100 GPD. So it seems to me I need to lower the flow even more. Looks like I am getting 400 ml of post RO/DI water minute and it needs to be around 290ML

 

[ichthyman]

You will burn up resin much more quickly with that membrane, which is why I avoid their use, be sure to pay close attention for exhaustion of the DI media. A second "true" RO membrane run parallel or in series is a better long term economical choice for our application.

Slowing down total flow through may also help those lower quality carbon blocks do a better job too. However, the only way to know for sure would be to test free and total chlorine before and after. When new they may be capable of removing chloramine but for how long is the question. Again, watch the DI resin for exhaustion as it will be your only protection.

You didn't mention which sediment cartridges used but as general rule, smaller micron mesh will protect and extend the life of all downstream cartridges the best. Around here, without the use of 1 or 0.5 micron sediments cartridges downstream carbon cartridges typically become physically clogged and therefore about useless long before chemical exhaustion. If chlorine is present, damage to the membrane is done.

 

[asmodyus]

You didn't mention which sediment cartridges used but as general rule, smaller micron mesh will protect and extend the life of all downstream cartridges the best. Around here, without the use of 1 or 0.5 micron sediments cartridges downstream carbon cartridges typically become physically clogged and therefore about useless long before chemical exhaustion. If chlorine is present, damage to the membrane is done.

I do not remember what micron my sediment is but I have the Sediment cartridge, a 5 Micron Carbon block cartridge, and a 1 micron Carbon block cartridge for chloramines than my membrane. Do you think I might need to get another DI Cartridge?

 

[ichthyman]

Do you think I might need to get another DI Cartridge?

I don't know. Appropriateness and longevity depend upon the specs of the resin. Not all resin is created equally and they have vastly different intentions of use. Most, vendors and hobbyist alike, chose whatever the cheapest product possible without doing a real economic comparison.

With me being who/what I am, this conversation could be construed by some as me treading upon RC's User Agreement. I've given you the right path(s) to follow but need to step away now.