Indoor Low ph in rain water?

[Justinsane]

Hiya all.

I use rain water for my girls.

Yesterday i did a ph-test on my rain water and i get an 4.9 reading...
did a reading on my tap water... 8.1 as always... nothing wrong with my ph meter then.
Another test on the rain water...another 4.9. Sounds very low to me. Or?

The water was pretty cold at the time i did the test, so i took a bottle and warmed it up a few degrees. Did another test and got a 6.2 reading.

So what is up with this?

Can i use the water?

Peace and Love Justin

 

[namvet]

PH changes with water temp and should be checked at room temp unless you have a ph meter that has auto temp compinsation.Theres nothing wrong with your rain water so go ahead and use it.

 

[Justinsane]

PH changes with water temp and should be checked at room temp unless you have a ph meter that has auto temp compinsation.Theres nothing wrong with your rain water so go ahead and use it.

Ok, thanks dude.

What is the best temperature on the water when feeding?

 

[Muddy]

Namvet is right on, temperature effects the pH reading. That's one reason I chose the Hanna Combo meter. Besides reading pH, TDS and PPM, it has automatic temperature compensation and gives an accurate reading regardless of the water temperature.

I also use rain water for my grows. Room temperature is fine. In the winter I fill jugs and store them in the house for at least a day before using so they can warm up to room temp. In the summer I use it straight from the catch barrel. Mine tends to run a higher than yours, usually around 7.5 pH and 60 - 80 ppm. When I add my nutrients is brings it into a good range without the need for any pH Up or Down. In your situation, with it starting out lower, it's very likely you will need some pH Up after adding your nutrients.

 

[Justinsane]

Namvet is right on, temperature effects the pH reading. That's one reason I chose the Hanna Combo meter. Besides reading pH, TDS and PPM, it has automatic temperature compensation and gives an accurate reading regardless of the water temperature.

I also use rain water for my grows. Room temperature is fine. In the winter I fill jugs and store them in the house for at least a day before using so they can warm up to room temp. In the summer I use it straight from the catch barrel. Mine tends to run a higher than yours, usually around 7.5 pH and 60 - 80 ppm. When I add my nutrients is brings it into a good range without the need for any pH Up or Down. In your situation, with it starting out lower, it's very likely you will need some pH Up after adding your nutrients.

So i did. Was 5.8 after ferts. So i tiny bit ph up did the trick. Cheers

 

[gtron]

Northeast US tends to have more acid ph than southern or western US does due to dioxides released by industry. Better than it was in the 70's but still an issue.