Water pH for my phals

[en3rmax]

Hi again OB,

I've been testing some water pH's tonight as my mate brought his tester he uses for his marine fish tank.

I live in Birmingham UK and my tap water was pH was 9.6

I've been collecting rain water and the pH was not as pure as i thought at 9.3

Then i tested a bottle of mineral water and the pH was 6.9

With these results is it pointless to water my phals with rain water as the pH was pretty much the same as my tap water?

The mineral water was best so should i use this?

[neb]

what do you store the rain water in???

[en3rmax]

I collected the rain water in a bucket then stored it in a 25 liter water container

[Ray]

Sounds like it's getting contaminated somewhere. It should be somewhere closer to 6.

[camille1585]

Are you testing with strips/drops or with a pH probe? Those usually need to be cleaned off in distilled water between uses (at least the ones I use in the lab do) or else you can get inaccurate readings. Rainwater pH should be much much lower than that, close to 6 like Ray mentions.
Are you collecting the rainwater from the runoff from the roof? Could be that stuff on the roof contaminates it.

[tucker85]

As Ray said, rain water will have a lower pH than that. You can bring the pH of your tap water down with vinegar. I use 1/4 teaspoon of vinegar per gallon to reduce the pH of my tap water. People do grow very nice orchids with hard water though. If your plants are growing well you may want to just keep doing whatever you're doing now.

[Eyebabe]

Wow 9.6?? That is a bit too high for orchids.
You won't notice it at first, but your root systems will slowly feel the ouch.
Ray's website has lots of great information about water quality and things to do to lower the pH.

[silken]

I was using our tap water which is 8.5 to 9 and seem to always be struggling with root loss on many types of orchids. Partly it may have been my watering too much. But I have switched to rain water (haven't tested the pH) and noticed an improvement quite quickly. Especially my phrag and paphs. am hoping over time, the catts will be more robust too.

[en3rmax]

Originally Posted by camille1585

Are you testing with strips/drops or with a pH probe? Those usually need to be cleaned off in distilled water between uses (at least the ones I use in the lab do) or else you can get inaccurate readings. Rainwater pH should be much much lower than that, close to 6 like Ray mentions.
Are you collecting the rainwater from the runoff from the roof? Could be that stuff on the roof contaminates it.

Hi Camille, it was a pH probe we tested with and we just tested one type of water to another one right after, i didn't know that was wrong.

The rain water did come from a runoff on my roof, i will have to test some rain that falls straight from the sky into a bucket.

My mate has only had the pH probe a few weeks he said he calibrated it with some liguid, i think it's the yellow greenish one with a 7 on it, i'm thinking did he calibrate it right.

[camille1585]

Rinsing is always good, but lack of it probably doesn't completely explain the super high pH for the rainwater. I think if you were to collect the water straight from the sky it would be much lower.

A pH of 9.5 ish is much too high for practically all plants, let alone orchids. Most nutrients can no longer/ are veru poorly taken up by the plant at that pH. The optimal nutrient availability is around pH 6.5