Water Question - I thought this was impossible

[gingerbeer 322]

Testing my water from my rain water tank I observed the following:

pH 7.2

KH 30 mg/L

GH 20mg/L

I cannot understand how soft water can have a neutral pH and hold it so well.

Please explain?

Steve

[japes 1]

What kind of tank is it? Interesting readings, my rainwater tests pure, pH 6.0 (low as my kit goes), 0 dgH/dkH.

[serenitynow 0]

Checked the bottom of tank for any dead critters/skeletons?

Age of test kit?

[gingerbeer 322]

I checked the hardness kit by cheking my tao water 0 and measures matched expected. Similarly checked pH kit against another kit.

The tank is not steel - but not sure what sort of plastic.

Given the relative GH and KH measure - looks like all hardness is calcium - given the accuracy of a test kit.

Tommorrow I am going to try and crash the pH in an emptry tank and see what happens. With those reading the pH should be highly unstable.

[raff 0]

I'd like to add to this. I don't have KH or GH readings, but last time I tested the rain water here at my place, the pH was 8.2-8.4. My understanding was that rainwater should be soft/acidic? Any thoughts?

[japes 1]

I'd like to add to this. I don't have KH or GH readings, but last time I tested the rain water here at my place, the pH was 8.2-8.4. My understanding was that rainwater should be soft/acidic? Any thoughts?

I'm very far from a water expert, but I believe that due to the basically (optimally) non-existent Carbonate Hardness in Rain Water, it can very easily inherit pH from anything it's stored in/with.

[Rod 188]

Steve....

Pure water is neutral....7

Rainwater generally becomes acid due to co2(or pollutants) in atmosphere

must be something leaching into water(this goes for raff too)

Raff.... is it a concrete tank?

[raff 0]

Steve....

must be something leaching into water(this goes for raff too)

Raff.... is it a concrete tank?

It's a poly tank, and the water is pumped through normal irrigation piping. That's all I can really tell you. I was under the suspicion that something was leeching as well, but I really have no experience with this, so I have no clue.

Thanks for the heads up too Japes, might have to do a little research about water quality when I get a chance.

[jimbozed 9]

bit off track but a good read

http://fins.actwin.com/mirror/begin-chem.html#altering

[gingerbeer 322]

Steve....

Pure water is neutral....7

Rainwater generally becomes acid due to co2(or pollutants) in atmosphere

must be something leaching into water(this goes for raff too)

Raff.... is it a concrete tank?

If anyone is looking for me a coffee and fishchicks tommorrow I will be the guy with the large dunces cap on.

I have been changing my susbstrate ove to sand and noticed my pH in newly set up tanks is different - been checking everything - forgot the basics. {insert simlie with a big dunces cap hitting brick wall here}

[raff 0]

Steve....

must be something leaching into water(this goes for raff too)

Raff.... is it a concrete tank?

It's a poly tank, and the water is pumped through normal irrigation piping. That's all I can really tell you. I was under the suspicion that something was leeching as well, but I really have no experience with this, so I have no clue.

Thanks for the heads up too Japes, might have to do a little research about water quality when I get a chance.

Sorry to bump an old thread but I wanted to ask another question building off this.

I was thinking about my water problem today (rainwater comes out of the tank at 8.2-8.4 pH). I realised that the pipe work to carry the water to the tap was buried in the ground and concreted over the top. Now, it looks like the people who did the concreting didn't do a very good job. So, if the pipe carrying the rainwater from the tank was punctured and the water was running over concrete, would that be a possible place where something is leeching into the water? Would this scenario raise the pH of the water?

Thanks.

[rex82 14]

i can put my money on everyone with high ph readings in thier rainwater having a tiled roof. those with a more acidic reading will have a colourbond sheeted roof. not rocket science whats going on there i think.

[raff 0]

i can put my money on everyone with high ph readings in thier rainwater having a tiled roof. those with a more acidic reading will have a colourbond sheeted roof. not rocket science whats going on there i think.

I do have a tiled roof. I think my next step will be to take a sample to test straight from the tank to eliminate the pipe work.

I never thought about that rex, thanks for the info.

[rex82 14]

put 1 bucket in the rain, check the ph, kh and gh of this......it should read as follows ph ~ 6 and 0 kh and gh.

the tiled roof will have a ph of ~7 and show a small reading of gh and kh

[raff 0]

put 1 bucket in the rain, check the ph, kh and gh of this......it should read as follows ph ~ 6 and 0 kh and gh.

the tiled roof will have a ph of ~7 and show a small reading of gh and kh

Will do, but I'm getting a reading of 8.2+ pH so thats where my thinking of something leeching in came from. Thanks.

[rex82 14]

depends how well sealed the roof tiles are.

[raff 0]

Thanks for your help and info rex, I'll start doing some testing soon.

[Zook 0]

Hi every one, this is actually my first post on this forum.

I also have been experiencing unusual water paramaters from my rain water tanks. I have two concrete and one poly, fed from seperate colourbond roof areas. While tile and metal roofing may slightly change water I don't think it's whats going on.

Does any one remember the big dust storm a while back? After that any rain that fell was loaded with dust from central and western Queensland and further. The dust that had been collected came from areas with histories of high usage of phosphate and nitrogen based fertilisers, also areas of acid sulphate and phosphate soils. It reaked havoc on peoples swimming pools. My tank water was affected until the more recent rains and flooding gave them a flush.

Just a thought.

[rex82 14]

good point zook! didn't think of that one. alot of things can alter your readings with rainwater due to the fact it has no buffering capacity.