RO water with high pH...why?

[khemo]

Hey guys

I bought a new RO unit from peter at PSI filters and received it the other day. I just tested it today and the water is comming out at pH= 7.8 which is higher than my tap water pH which is 7.2. Any reason for this?

Before you ask, I did not get the waste water and RO water tubes mixed up as the TDS is low in the water I'm testing.

cheers

[khemo]

Anyone?

hmm...this forum is so dead....no one keeps discus no more :\

[Hassles]

You may read some posts here from members expressing their concerns over the same problems you are experiencing. Apparently RO water can leach some minerals out of some substrates and this can cause the PH levels to rise above those you would expect. What else is in the tank you're adding the RO water to ?

[brad_v]

I think the ph is more a measure of the potential rather than the concentration. It will still have less bufferring capacity and be easier to drop to and maintain a lower ph.

[khemo]

You may read some posts here from members expressing their concerns over the same problems you are experiencing. Apparently RO water can leach some minerals out of some substrates and this can cause the PH levels to rise above those you would expect. What else is in the tank you're adding the RO water to ?

Hi mate

Thank you for your reply

The tank only has aquasoil in it and nothing else apart from the eheim outlet and inlet.

However the water has high pH comming straight out of the RO unit. Maybe the membrane has some residue in it that is causing the high pH?