Deioniser sachets

[Chris Hogg]

Occasionally, I need to measure the pH of garden soil. Ideally, I should use de-ionised water for this, so that the pH of the water doesn't influence the result. But I don't have any, and my freezer doesn't generate sufficient 'frost' to make it an alternative. What I'd like to find is a source of sachets of deionising resin beads, a bit like tea-bags, that I could drop into a glass of water and leave for a while, before removing it and using the water for my pH measurement. But I can't find anything resembling that on the 'net. Does anyone know if such things are available, and if so, where?

[The Natural Philosopher]

Just boil ordinary water or buy some de ionised from e.g.Halfords

[David]

Occasionally, I need to measure the pH of garden soil. Ideally, I should use de-ionised water for this, so that the pH of the water doesn't influence the result. But I don't have any, and my freezer doesn't generate sufficient 'frost' to make it an alternative. What I'd like to find is a source of sachets of deionising resin beads, a bit like tea-bags, that I could drop into a glass of water and leave for a while, before removing it and using the water for my pH measurement. But I can't find anything resembling that on the 'net. Does anyone know if such things are available, and if so, where?

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Do a google search for deionising filters as part of a reverse osmosis system.

I'm not aware that they are sold as loose crystals but it should be a good starting point.

David

[Max Demian]

Why would boiling water change the pH of water? (I think water from the tap is pretty much neutral in any case.)

[Chris Hogg]

but that wouldn't deionise it.

That's a better idea. I'll look in a garage shop when I next get fuel

- they usually have a small range of things like that, oils, greases, antifreeze etc so might have deionised water.

[Chris Hogg]

Ah, found this

which I guess would be OK. I could just use a teaspoonful at a time in a mug of water and then discard it. Not quite sachets, but near enough perhaps.

[Jeff Layman]

That may depend on definitions. Hard water contains calcium ions, some of which are as the bicarbonate salt. Boil that and it turns to carbonate. Same calcium, but the bicarbonate is soluble, the carbonate effectively insoluble.

[charles]

you need to collect the vapour (steam) that boils off.

[The Natural Philosopher]

it will take out the worst of the carbonates

Or order online. Tescos may do it for steam irons as well etc.

[Chris Hogg]

Depends on the type of hardness. What you and TNP are describing is 'temporary hardness', but if the hardness is due to calcium sulphate, i.e. gypsum, or magnesium sulphate, it's 'permanent hardness' and boiling it won't change it. Now the water down here doesn't contain much in the way of either calcium nor magnesium salts (but there is a little of both - the water company supply analyses on request - I requested), so that particular discussion is a little academic, but there are other salts, for example aluminium sulphate is often added to water down here to flocculate suspended matter and aid clarification. I'd be much happier with the results of my pH test if I knew the water I was using was properly de-ionised. I believe my soil here is around pH 6.5, but then, so is the water, so am I measuring the soil pH or the water pH?

[Bob Eager]

I get mine from the local ironmongers.

[harry]

Collect the ice when you defrost a freezer/fridge and melt. This is "distilled/de-ionised water".

[Bob Eager]

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You haven't read what he said, have you, SFB?

[alan_m]

Some supermarkets sell deionised water for use in steam irons.

[Andrew]

Buy a karcher window vac and wait for some colder weather to collect condensation.

How about trapping the drain from your cars A/C ?.

[alan_m]

The resin is used as part of a 3 or 4 stage filter Stage 1 Mechanical filter to remove large particles Stage 2 Activated charcoal filter Stage 3 Reverse Osmosis filter Stage 4 Resin filter

The resin you list is used to fill a large tube (perhaps 5cm diameter x

30cm length) where water enters at one end and exits at the other, often with a restricted flow.

[Jeff Layman]

In terms of ionic effect on pH, I think the only metallic ions of interest are calcium and aluminium, with calcium as either bicarbonate or carbonate, and aluminium as sulfate. But the Ca solutions are weakly basic, and although aluminium sulfate solution can be fairly acidic, that would only be at high (and therefore toxic levels - although it has been known in Cornwall!). I doubt either in the sort of strengths soft water would contain would have any effect on pH measurement.

I'd be much happier with the results of my pH test if I

Well, it's always best to have deionised water as I think there are some ions, and perhaps other chemicals, which can have an effect on pH electrodes. Or are you using indicator solution/paper to check the pH?

As to exactly what you are measuring, well, it's the result of the reaction between the water and the soil. It not only depends directly on the cations and anions, but perhaps any buffering agents in the soil. Usually, though, the amount of water used would far exceed what is soluble in the soil. If you get a chance, it would be very interesting to compare the results using tap and deionised water.

[RJH]

Fill pan with an inch or 2 of water and place a china bowl in the water. Fit the lid upside down and boil - the water condenses and drips off the lid handle into the bowl.

[Andrew]

If there is a colour strip to indicate the pH, what does it show for tap water alone ?. Once you know, you can just shift your actual soil reading.

If you know what plants you have, do you really need to know ?.

Lime hating plants don't do well on Sussex chalklands and things like rhododendrons need loads of leaf mulch to keep the pH down.

Lawns and most vegetables love lime.

Roses like it in essex and were much happier when we all burnt coal, presumably because the sulphur kept black spot and other nasties at bay.

Rhubarb only grows properly in the Yorkshire triangle, or so they like us to believe.

[alan_m]

Info S.E.Essex

Tap water ph 6.5, TDS 350

De-ionised water ph 7.0, TDS zero (filtered tap water 36 hours ago)

Readings taken with a cheap electronic ph meter (£12) and TDS meter (£5)