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Caitlin Renee 6/29/07
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Discussion Starter #3
thats what i thought. Well this isnt good then. My pH monitor is calibrated. and reads 7 and 10 in the right solutions. Reads 8.3 in my tank. When i go to check the pH in my ro/di top off water it reads 9.2!?!?!? what has happened?
 

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Stinky Slimey FEESH
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RO/DI water should be 7 (neutral) or even a little less, on the slight acid side.

Have you changed your carbon block or DI cartridge lately? I'm thinking when your unit starts making alkaline water it means the membrane is history - but I could be wrong.....

HHC
 

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Maybe you need to change your filters still. Chlorine is basic, and it seems as if MAYBE a little of that was still left in your RODI water, making your water become basic as well. Just a shot in the dark. But SOMETHING basic is still in your water, that you filter is not filtering out.

Have you done a chlorine test? You can use those cheap ones for pools.
 

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Interesting my RO PH is about 9.2 as well. PH monitor was just calibrated and the RO unit is only about 2 months old...I'll check my chlorine and get back...
 

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Caitlin Renee 6/29/07
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3,199 Posts
Discussion Starter #11
Interesting my RO PH is about 9.2 as well. PH monitor was just calibrated and the RO unit is only about 2 months old...I'll check my chlorine and get back...

mine isnt very old either. what ro/di unit do you use?
 

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Perfeshunal Hikk
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I read somewhere here on TRT about it (I think it was one of tdwyatt's posts) about testing pH of RO/DI water and the whacky results you can get from it.
 

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I read somewhere here on TRT about it (I think it was one of tdwyatt's posts) about testing pH of RO/DI water and the whacky results you can get from it.
Yes, I think that's true. I've seen it first hand, and think I've also heard that too. Something about how pure ro/di water lacks ions or something which throws off the meters that we use.
 

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In the Final Effluent pH section, it states that meters have a difficult time reading pH accurately due to lack of buffering capability of the water. Your best bet is to make sure that you have correct pH after you add your salt and let it mix for 24 hrs.
Yup, doesn't give accurate readings.
 

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Perfeshunal Hikk
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Here is a great article about RO/DI water:

http://reefkeeping.com/issues/2005-05/rhf/index.php#8

In the Final Effluent pH section, it states that meters have a difficult time reading pH accurately due to lack of buffering capability of the water. Your best bet is to make sure that you have correct pH after you add your salt and let it mix for 24 hrs.
That reads and seems familiar to me. It may be where I read it. Just glad someone had a link so I didn't think I was going crazy trying to remember it.
 

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That reads and seems familiar to me. It may be where I read it. Just glad someone had a link so I didn't think I was going crazy trying to remember it.
That's good to know...thought I was going to have to figure out what was wrong with my RO!

Thanks!
 
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