RO/DI filter and higher PH levels

[cybercron]

Hello,

I noticed that water filtered through my RO/DI unit has a higher PH than my tap water. My tap water has a PH of 7.9. After running it through my RO unit it becomes 8.9. I have tested with liquid tests and a digital PH tester with identical results.

I am using the AquaFx Barracuda RO/DI Filter.

Is this normal?

Thanks,

Van

 

[reefrunner69]

No, it's not normal. The ph of RO/DI water should be around 6.5-7.0 depending on the quality of water going in. What is the TDS of the product water? Is your digital ph meter calibrated to read ph that low?