TDS Meter Use

BradMugs · 05/17/2009, 09:23 PM

This hobby is great - I had a question about RO/DI water and getting a TDS meter - saw the other thread about it and it answerd some of my questions so this is what I've got left to ask.

1 - I see TDS meters that read the end product and some that read the before and after - the price differance isn't all that great but I don't know if I need the before and after.

I'll explain my setup - I've got one of those 50 gal tanks that was used by one of the soda manufactures to ship their syrup - picked it up for like $15 and cleaned it really well (very easy to clean actually). With a 100G/day RO/DI unit it didn't take long to fill - I fitted it with a float and a syphon to get the water out and all the openings are pretty much sealed - not air/water tight but sealed. This is great as when I need water for top up or to give my son when he's in town to take a supply home for is tank I have plenty on hand. Anyway, back to my question - what makes more sense the dual meter which would read what is in the line or the small meter that reads what I'm pumping out at the time? And why do you think one would be better than the other (I don't mind straight dual/single answers but I learn nothing from that).

2 - If the dual meter where should they be connected? I'm sure one after my final filter but should the first be where the tap water comes in or elsewhere?

3 - based on my setup should I be concerned? Is my RO/DI water going to be OK - I never empty the tank - at most maybe 25 to 30 gal before it's refilled once a month.

Thanks,

Brad

drummereef · 05/17/2009, 10:44 PM

1. It can be handy to see what the reading is after the RO stage. This is nice because you can monitor the efficiency of the RO membrane and know when it's time to change it. Final product testing is necessary.

2. I would insert the first line test right after the RO membrane stage. The second test line would be on the final output of the filter, after the DI stage.

3. There will be most likely some TDS creep as the water sits, but you'll just have to monitor it. I would try and keep your filtered water as low as possible, 0 tds being ideal.

Whys · 05/17/2009, 11:34 PM

I have one that measures both the in and the out, but the in reading is really only useful for insuring my meter is working. Otherwise it would just read 000 all the time and I'd have to wonder if the contacts were still working.

BradMugs · 05/18/2009, 09:11 PM

drummereef - thanks - I think a lot of 0 reading would be ideal - just not what I can seem to get to, not sure how others do it.

Whys - if your 000 ever went to anything else (like match the first reading) you would know your final filter was not working.

It's sounding like the inline is great to monitor things but in reality the final water is what I need to check - but then w/o the inline how does one know if your filters fail... I'll probably go with the dual inline and then pick up a small tester down the road.

Thanks,
Brad

Flipper62 · 05/18/2009, 09:24 PM

I have a Ocean Reef +1 from the Filter Guys, It has a dual TDS meter. I have the " IN " meter after the RO filters...Before the DI...And the "out " on the final line out.

HOWEVER....I only use this as a guide to the TDS reading & to keep an eye on the filters.

I use a COM-100 Portable TDS meter for an accurate TDS reading.

If the COM-100 has a good TDS reading.....I'm good to go with the water.

Whys · 05/18/2009, 09:49 PM

Quote:

Originally posted by BradMugs
Whys - if your 000 ever went to anything else (like match the first reading) you would know your final filter was not working.

True, but after 7 months of use, it still reads 000. So if I didn't occasionally test the in-line, how would I know?

drummereef · 05/18/2009, 11:40 PM

Quote:

Originally posted by BradMugs
drummereef - thanks - I think a lot of 0 reading would be ideal - just not what I can seem to get to, not sure how others do it.

If your DI resin is fresh, or relatively new at the least, you should be pulling 0 TDS after the DI stage no problem. Are you testing as you are pulling water directly from the RO/DI unit or waiting until the reservoir has filled? Trying to get to the bottom of why you aren't getting 0 TDS....

THE ROOK · 05/19/2009, 06:33 AM

Both would be the best plan. In-line are great for keeping an eye on the membrane & DI. Handhelds are good for quick checks & to make sure your container isn't causing a TDS rise.

You can test everything with a hand-held, it's just a little more work. I pop the line off after the membrane once a month to make sure all is well.

05/17/2009, 09:23 PM	#1
BradMugs Registered Member Join Date: Nov 2008 Location: Aurora, CO, USA Posts: 440	TDS Meter Use This hobby is great - I had a question about RO/DI water and getting a TDS meter - saw the other thread about it and it answerd some of my questions so this is what I've got left to ask. 1 - I see TDS meters that read the end product and some that read the before and after - the price differance isn't all that great but I don't know if I need the before and after. I'll explain my setup - I've got one of those 50 gal tanks that was used by one of the soda manufactures to ship their syrup - picked it up for like $15 and cleaned it really well (very easy to clean actually). With a 100G/day RO/DI unit it didn't take long to fill - I fitted it with a float and a syphon to get the water out and all the openings are pretty much sealed - not air/water tight but sealed. This is great as when I need water for top up or to give my son when he's in town to take a supply home for is tank I have plenty on hand. Anyway, back to my question - what makes more sense the dual meter which would read what is in the line or the small meter that reads what I'm pumping out at the time? And why do you think one would be better than the other (I don't mind straight dual/single answers but I learn nothing from that). 2 - If the dual meter where should they be connected? I'm sure one after my final filter but should the first be where the tap water comes in or elsewhere? 3 - based on my setup should I be concerned? Is my RO/DI water going to be OK - I never empty the tank - at most maybe 25 to 30 gal before it's refilled once a month. Thanks, Brad

05/17/2009, 10:44 PM	#2
drummereef Team RC Member Join Date: Jul 2006 Location: STL Posts: 14,754	1. It can be handy to see what the reading is after the RO stage. This is nice because you can monitor the efficiency of the RO membrane and know when it's time to change it. Final product testing is necessary. 2. I would insert the first line test right after the RO membrane stage. The second test line would be on the final output of the filter, after the DI stage. 3. There will be most likely some TDS creep as the water sits, but you'll just have to monitor it. I would try and keep your filtered water as low as possible, 0 tds being ideal. __________________ -Brett 180g Marineland Starfire In-Wall 278 gallon system

05/18/2009, 09:24 PM	#5
Flipper62 Premium Member Join Date: Apr 2008 Location: Naperville, Il. Business Owner, President & CEO Posts: 3,045	I have a Ocean Reef +1 from the Filter Guys, It has a dual TDS meter. I have the " IN " meter after the RO filters...Before the DI...And the "out " on the final line out. HOWEVER....I only use this as a guide to the TDS reading & to keep an eye on the filters. I use a COM-100 Portable TDS meter for an accurate TDS reading. If the COM-100 has a good TDS reading.....I'm good to go with the water. __________________ If todays automobile had followed the same development as the computer, A Rolls Royce would cost $100.00. It would get a million miles per gallon, but it would explode once a year killing everyone inside." Current Tanks... 90 gal Reef... My awesome Office BioCube....( 180 was on hold ..no time ) ... The 180 gal has been sold...Yay..yay..yay. Hobby Experience: 19 years Reef...22 years FW

05/17/2009, 11:34 PM	#3
Whys Moved On Join Date: Mar 2008 Location: Spokane, WA Posts: 3,263	I have one that measures both the in and the out, but the in reading is really only useful for insuring my meter is working. Otherwise it would just read 000 all the time and I'd have to wonder if the contacts were still working.

05/18/2009, 09:11 PM	#4
BradMugs Registered Member Join Date: Nov 2008 Location: Aurora, CO, USA Posts: 440	drummereef - thanks - I think a lot of 0 reading would be ideal - just not what I can seem to get to, not sure how others do it. Whys - if your 000 ever went to anything else (like match the first reading) you would know your final filter was not working. It's sounding like the inline is great to monitor things but in reality the final water is what I need to check - but then w/o the inline how does one know if your filters fail... I'll probably go with the dual inline and then pick up a small tester down the road. Thanks, Brad

05/19/2009, 06:33 AM	#8
THE ROOK Registered Member Join Date: Jun 2008 Location: Springfield, MA Posts: 2,100	Both would be the best plan. In-line are great for keeping an eye on the membrane & DI. Handhelds are good for quick checks & to make sure your container isn't causing a TDS rise. You can test everything with a hand-held, it's just a little more work. I pop the line off after the membrane once a month to make sure all is well.