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Discussion Starter · #1 ·
I jsut bought an RO filter and after flushing the membrane for 3 hours took some measurements.

KH- 0/1
GH- 0/1
PH- Comes out at 7.6

My question is that is, should the ph be coming out that high? I checked it against the stuff I bought from the culligan store and it checks at ph 6.6 (note this water has been sitting for a week in a 5g jug)

Just want to make sure all is well before I start filling up my jugs for the week.

Craig
 

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Not sure about just RO but with RO/DI pH is difficult to test accurately. I'd let it sit and then retest it. But with those low GH and KH numbers I'd just ignore the pH. It should be within a couple tenths of 7 after stabilizing/equalizing.

Do you know the TDS?

EDIT: The pH testing problem with pure water is it's low buffering capacity and how the pH test chemicals work. Even pH probes don't work well in this case.

SteveU
 

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Discussion Starter · #3 ·
Not sure about just RO but with RO/DI pH is difficult to test accurately. I'd let it sit and then retest it. But with those low GH and KH numbers I'd just ignore the pH. It should be within a couple tenths of 7 after stabilizing/equalizing.

Do you know the TDS?

SteveU
Nope I'm waiting on a TDS meter to arrive. It does taste fine though.

Craig
 

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I have the same issue with my RO water, i dont remember what it tested at now, but it was alot higher than i expected. I just pretty much ignore it though like GTR said. I use 1/3 tap and 2/3rds RO water, and i havent tested my water in a LONG time...everything is thriving though
 

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Discussion Starter · #5 ·
Thanks, after Googling around I see that PH can very alot depending on the intake water and the RO system.

I have tested the water after sitting out for a couple of hours and the color is lighter then the first test so the PH will probably level out somewhere in the 7.2 vacinity.

Hope to get my TDS meter in soon so I can check the quality of the water prior and after the filter.

This is for my shrimp tank and for drinking water so all should be good.

Craig
 

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Don't test your PH on RO because it is very unstable. You will have to add something like Equilibrium to stabalize the water first. I add the RO water to my tank and take readings an hour after. I only do 20% water changes and let the RO run into the tank (takes several hours to fill) by refilling slow, I am not shocking the fish.
 

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Discussion Starter · #7 ·
Figured I would update as I jsut picked up my TDS Meter. A dual HM inline unit for my system.

TDS out of Tap - 122ppm
TDS out of RO - 011ppm

Looks like it is working just fine.

Craig
 
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