RO/DI Readings

[TygGer]

I have a Ebay 100gpd 6 stage RO/DI system and a Hanna TDS meter.

Here are my readings:

Tap - 179
After the first 3 stages and RO membrane - 13
After the first 3 stages and RO and DI - 11/12
And after the final carbon - 15
Waste - 240

I understand that teh 100gpd RO membrane does not remove as much TDS as the 75gpd membranes, but is it normal to get a reading of 13ppm after only the RO stage?

My DI cartridge is one of those non-refillable cartridges. It does not seem to be doing anything and the final stage carbon seems to be leaking contaminents back into the water. I just took off the final carbon stage since it's not needed.

Im wondering why the DI stage is worthless...

The whole system is brand new and I ran it for about 6hrs.

 

[PatM]

I do not know a ton about di but ro's I know. Did you flush all filters before using. Any carbon filters should be flushed for a minimum of one minute before use. There is no reason for your tds to rise back up after coming in contact with the carbon. I could be wrong but I don't think the di's purpose is to remove tds, though you do seem to have positive results after the di so it does seem to be doing something. IMO a TDS reading of below 15 ppm is great and I wouldn't sweat it. The readings will probably get even lower after a couple weeks of ro use.

 

[scuba_steve]

its way to new to tell imo ! when i bought my kent ro unit it stated to run it for 24 hours straight to make sure the membrane was soaked then add the di unit! also the carbon will raise those levels for sure ! give it a week and re-test im kinda curious what your reading will be then

 

[cmor1701d]

I ran it for about 6hrs

I agree with Keith, you need to run this longer before you see the best results. After break-in the tds after the DI should be 0. I allow a 0-2 range for outside contaminants that might get in before I test (airborne dust, etc.).

More tah nthat measn it's time to change the DI cartridge. Others here will let it go higher.

 

[TygGer]

Ok, guess I need to run the RO/DI even longer.

Some have recommended me to buy a new DI cartridge/housing because the one I have may be faulty from the start.

Doing a search, the average TDS after the RO membrane should be between 3-10 and 0-2 after the DI. A 100gpd membrane has a 90% rejection where as a 75gpd membrane has >98%.

If after running the filter for a few more hours to no avail, Ill consider buying a new DI cartridge or housing.

These are the two I'm considering:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=46310&item=4344482864&tc=photo

and

http://www.buckeyefieldsupply.com/showproducts.asp?Category=39&Sub=1

One's a horizontal canister and the other is a vertical housing. Anyone have experience with either of these?

 

[Phyl]

If, after running it for a little while longer, you're not getting the TDS you expect you should go back to the manufacturer to have them *give* you a new membrane if the first is faulty. That is the least that they could do considering it has never worked properly.

 

[TygGer]

The problem is I bought the system on ebay over 5 months ago during the planning stage of my first large tank. Then I got overwhelmed with the plumbing and everything that comes along with setting up a large tank (sump, pluming, equipment, etc)

I just got the RO/DI setup recently

 

[Phyl]

I would still go back to the manufacturer. You're just getting it running. They should stand behind their product!

 

[TygGer]

I can try... It was bought on ebay so I worry about cust. service.