Ph Of Ro Water

[hunterm8]

What should the ph of RO water be? I thought it should be 7 but my ph meter goes straight up to 10 +! I thought this might be a false reading due to purity so i added it to tap water, the reading still went up!

Also if i just wanted to use RO water what do i need to add to it, i have tried 'RO right' but this doesnt seem to give it any KH!

cheers mick

 

[andywg]

The pH of RO water will be pretty much 7 as it is so pure. The downside is there is nothing in it for the test kits to react with, therefore they will give wild results. The only real way to test RO water is a TDS meter.

As far as I recall the RO additives for FW are to put back in essential minerals rather than buffer the water's hardness.

 

[Bignose]

By definition, the pH of pure water shuld be 7.0, but in practice, since the water is so pure, the tiniest addition of most anything causes huge swings. This could be even the residue of tap water left on your pH meter, or residue from whatever the RO water was kept in. And, obviously, some kind of buffer will obviously need to be added, maybe you could post the ingredients list on your salt mix, and forum members could tell you what they are supposed to do. You could probably google them yourself, too.