Low ph 40 ppm ro water a clue?

I know you arent supposed to go by the straight ro water for the ph but the water out of the ro system reads about 40 ppm, when I add cal-mag then check the ph it reads around 6. Is this a clue as to what that 40ppm consists of that is getting through my RO filter?

@Renfro I already know you know a lot of this RO stuff... Do you know what it might be getting through?

Maybe I should add that it is well water, I have been using it and just using ph up getting it around 6.5 since I'm growing in soil and I'm checking the ph with strips so it's not a meter issue.

40ppm is high for RO water. Are the filters old?

RO and distilled will also absorb CO2 and create a weak carbonic acid so the pH will drop naturally.

No a couple months old and thats where it was putting it in originally, the system has a carbon filter it goes through after the tank, says it is to stop any odd flavor that may contaminate the water after sitting in the holding tank... Could that be the cause?

This is the ro system I bought

Because I've had recent troubles with meter accuracy....I would test to confirm my meter is reading bottled RO at zero.

TintEastwood said:

Because I've had recent troubles with meter accuracy....I would test to confirm my meter is reading bottled RO at zero.

Click to expand...

I'm not using a meter I'm using strips

TintEastwood said:

Because I've had recent troubles with meter accuracy....I would test to confirm my meter is reading bottled RO at zero.

Click to expand...

I also have had meter troubles, I have a meter that I haven't been able to correctly calibrate so it's been sitting in its box on a shelf for years and I figured strips are more reliable.