RO water reading 19ppm????

nemofish2217

New member
why would my RO/DI water be reading 19 ppm? i just changed the filters today.....could this be why? i tested my old RO earlier(before filter change) and it was 0ppm....my tap water is about 35ppm.... do i need to let the new ones run all night to flush out the new cartridges? i got all new ones except for the membrane...... including the DI resin.....thanks...

P.S. I am correct in thinking that it would not be good to use this water for a water change since it is so high, right?
 
I'd let it run for several hours at least and then check it again. 19ppm is a little high, but I'd use it. BEats tap water.
 
If it were me I'd let the water run for about 6 hours (depends what size container you have and how much water you want to make) and see if it zero's out. If not I would change the membrane.

Do you have a backwash valve on your RODI which self cleans the membrane? If so I would leave that on for a few minutes, might not be a bad idea to get one if you don't have one.

Except for when i change my membrane my tds always read 0 out (and my water is reading 540 in!!!) Only time I have had it not reading 0 is after a new change in membrane (normal) in which I do let it run for a few hours to zero it out.

Which brand RODI do you have?
 
the water general RO...got it on ebay a while back.... just checked it coming out of the "pure tube" and it is now reading 4ppm... so maybe it just needs to clean itself out? im pretty sure the membranes not bad, cause like i said, i tested some water earlier today and it was at 0ppm.... Do you think water with 4ppm in it is okay for a water change?
 
4ppm doesnt sound bad to me at all, and you'll probably be more than fine with it (some people use tap without RODI).

If your worried about harming your tank,don't ; it shouldn't be a problem. If you want to be picky about it (like I am :D) I would let it run some more since it seems to be cleaning itself out. (and thats the reason you got it, to get that 99.99% pure RODI water ;P right!)

4ppm is definately ok for a water change.
 
haha...thanks stinkintuna..... i think it is cleaning itself out....but maybe i should look into a backwash valve... anyone have any links to where i can get them?
 
TDS off my RO unit ( NO DI ) is 11 ppm and Ive been using it for 2 years. Of course I change my filters and its still 11ppm. I ve had no problems so Ive never seen the reason to install a DI unit.4 ppm is fine :)
 
35 ppm by far is the cleanest raw tap water I've ever heard of. My last few home's tap has ranged from 200-550.

If your current tank livestock is updated, and you intend the tank remain a Fish Only with Live Rock, I wouldn't hesitate using water with readings in the teens and low twenties for as long as its an FO. If you focused on mostly corals, then it would be a diff story.
JMO
 
how long would your filters last with 35 ppm in? I bet well over a year with a smaller tank. Mine is about 385 in and 0 after DI. I too have the water general 6 stage unit although i disconnected the 6th stage, no need.
 
its city water...i know, i was surprised too when the TDS meter read 35ppm... i double checked by testing some RO water right after and it read 0...and actually, this is the first time i have changed my filters...and i think i bought the unit back in the summer of 04.... so, yeah, i think i am getting pretty good mileage out of the filters. ;)

thanks for the links stinkintuna :thumbsup:
 
haha... i know... i have been letting it run for a while to try to clean itself out... im gonna go check it again to see where we are at...
 
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