Help with RO/DI purchase - Page 3

smleee · 08/23/2006, 12:49 PM

Quote:

Originally posted by Driftwood
Do you think the 2ppm could have leached from the container? If so should I look at a better container to use?

More likely, the container just had something in it. Brutes are good - the gray ones; they will have a "NSF" stamp on them.

eee

Driftwood · 08/24/2006, 06:21 AM

I put the T on after the RO and tested it. Those quick fittings are sweet. The output rom the RO membrane was 8ppm. The output after the DI was 1ppm, but after I let it fill the container overnight the water in the container tested at 0ppm.

I tested the water pressure and it was 110 psi. Is this an alright pressure for the filter?

Spuds725 · 08/24/2006, 08:15 AM

You sometimes get a little tds spike when you first start flow-- let it flush a little before testing---- if the container water is ok-- you are fine---

110 psi-- very high-- no booster pump??? You RO stage should work great at that high a pressure

Driftwood · 08/24/2006, 08:42 AM

No booster pump. I am connecting to the washer spicket in my basement. It is the first connection off the cold water line into the house. I can turn the house pressure up or down with a valve comming into the house. I have it set now so the shower has lots of pressure...

smleee · 08/24/2006, 11:38 AM

Quote:

Originally posted by Driftwood
I put the T on after the RO and tested it. Those quick fittings are sweet. The output rom the RO membrane was 8ppm. The output after the DI was 1ppm, but after I let it fill the container overnight the water in the container tested at 0ppm.

I tested the water pressure and it was 110 psi. Is this an alright pressure for the filter?

130>>8>>0 Is good. That means your membrane is working at about a 94% rejection ratio. Considering this membrane is old and I'm not sure if it's a Dow FilmTec membrane, 94% is ok (when you get to about 90% rejection you will want to replace with a 75GPD Dow FilmTec membrane - 98% @ 50psi). 110psi is quite high, I know there is an upper limit on pressures and you may be approaching it. Anything above 50psi is good and will produce favorable waste ratios and production rates.

eee

smleee · 08/24/2006, 11:43 AM

Quote:

Originally posted by Spuds725
You sometimes get a little tds spike when you first start flow-- let it flush a little before testing----

Very true.

Driftwood, now that you have an RO only tee, you can put a valve on it to flush the water at the start of each production so you don't waste the DI; many units already have this built in.

eee

Driftwood · 08/24/2006, 02:47 PM

Cool. How much should I bleed out? Would a gallon do it?

I just did a search on the filmtech membranes and the upper limit was 300psi. I guess I'm safe there. They had a few graphs in the PDF file. I guess they produce much more water at higher pressures.

Driftwood · 08/24/2006, 05:04 PM

So I blead out a gallon and tested that, it was 4ppm. Then I blead out another gallon to try for drinking and tested that, it was 0ppm. Does that sound right? 0ppm before the DI?

AZDesertRat · 08/24/2006, 05:21 PM

You have to keep in mind TDS meters are +/- 2% of full scale so there could be an error especially at lower levels. You are probably pretty good though if you indicate a 0. Most handhelds and especially the HM inlines are not real accurate nor sensitive at the lower levels, in mid range they are pretty good though.

Driftwood · 08/25/2006, 06:43 AM

I know it isn't perfect, but at least the meter gives me a good idea of how well the filters are working. I'll probably get a better meter down the road, and a second stage of DI as well.

Thanks for all your help guys!

AZDesertRat · 08/25/2006, 09:04 AM

Just enjoy the hobby, thats what its all about!

08/24/2006, 08:15 AM	#53
Spuds725 Registered Member Join Date: May 2005 Location: Toledo, Ohio USA Posts: 2,051	You sometimes get a little tds spike when you first start flow-- let it flush a little before testing---- if the container water is ok-- you are fine--- 110 psi-- very high-- no booster pump??? You RO stage should work great at that high a pressure __________________ "I only have time to neglect one tank"-- Me "I don't want to achieve immortality through my work, I want to achieve immortality by not dying"-- Woody Allen Current Tank Info: 125G mixed reef with 135G Sump

08/24/2006, 06:21 AM	#52
Driftwood Registered Member Join Date: Jan 2006 Location: Gardiner, ME Posts: 841	I put the T on after the RO and tested it. Those quick fittings are sweet. The output rom the RO membrane was 8ppm. The output after the DI was 1ppm, but after I let it fill the container overnight the water in the container tested at 0ppm. I tested the water pressure and it was 110 psi. Is this an alright pressure for the filter?

08/24/2006, 08:42 AM	#54
Driftwood Registered Member Join Date: Jan 2006 Location: Gardiner, ME Posts: 841	No booster pump. I am connecting to the washer spicket in my basement. It is the first connection off the cold water line into the house. I can turn the house pressure up or down with a valve comming into the house. I have it set now so the shower has lots of pressure...

08/24/2006, 02:47 PM	#57
Driftwood Registered Member Join Date: Jan 2006 Location: Gardiner, ME Posts: 841	Cool. How much should I bleed out? Would a gallon do it? I just did a search on the filmtech membranes and the upper limit was 300psi. I guess I'm safe there. They had a few graphs in the PDF file. I guess they produce much more water at higher pressures.

08/24/2006, 05:04 PM	#58
Driftwood Registered Member Join Date: Jan 2006 Location: Gardiner, ME Posts: 841	So I blead out a gallon and tested that, it was 4ppm. Then I blead out another gallon to try for drinking and tested that, it was 0ppm. Does that sound right? 0ppm before the DI?

08/24/2006, 05:21 PM	#59
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	You have to keep in mind TDS meters are +/- 2% of full scale so there could be an error especially at lower levels. You are probably pretty good though if you indicate a 0. Most handhelds and especially the HM inlines are not real accurate nor sensitive at the lower levels, in mid range they are pretty good though.

08/25/2006, 06:43 AM	#60
Driftwood Registered Member Join Date: Jan 2006 Location: Gardiner, ME Posts: 841	I know it isn't perfect, but at least the meter gives me a good idea of how well the filters are working. I'll probably get a better meter down the road, and a second stage of DI as well. Thanks for all your help guys!

08/25/2006, 09:04 AM	#61
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	Just enjoy the hobby, thats what its all about!