Re: Various

Brett Lymn (
Mon, 26 Jun 1995 17:36:25 +0930 (CST)

According to Peter Cole:
>> Regarding water purifiers/filters, I am not sure how
>> effective a carbon filter will be at removing inorganic
>> materials from tap water.
>I'm not sure it's 100% carbon - it may be carbon-based with something
>else as well. I ought to cut one open and have a look.
>I have sometimes not changed the filters as regularly as recommended,
>and it's noticeable that the compost suffers as a result - when I
>change them every 100 pints or so there's no problem (it's not easy
>keeping track of how much use they've had though - I just give it a
>couple of weeks between changes in the summer and less in the winter.)

Hmmm I would imagine that activated carbon filters would not be very
effective at getting out dissolved salts. I think they are popular in
aquariums for scarfing up dissolved organic muck - maybe you water has
a lot of this in it and not much salt?

>> I use rain water until supplies
>> run out in prolonged periods of dry weather - then I resort
>> to acidifieing tap water with citric acid. I still dont like
>> this solution as I am concerned about long term salt build
>> up in the compost.
>I guess that should precipitate out any salts. Do you see any deposits
>when you've added the acid? Maybe they'd be filterable (with a paper
>coffee filter or something,) after they've precipitated, or just don't
>empty the watering can and throw the dregs away...

I have not seen the original message for this yet but if his position
is anything like mine the main problem with tap water is plain old
table salt (NaCl). Here in South Australia we have water that is very
high in all sorts of dissolved minerals, including salt (apparently
this hard water is very good for beer making :*). I have been forced
to use tap water for watering my plants for an extended period and
have found white crystals on the top of my potting mix. I tasted the
crystals and found it to be salt :-( This was after carefully boiling
all the water and letting it stand before using it.

The problem with salt is that it is a chloride - most other chlorides are
soluble in water as well (if my inorganic chem memory is correct).
Sure, there are some that are not calcium is one, silver another but
actually acheiving the chloride precipitate means adding other things
to the water that may be even worse for the plants :-(

>re: RO - I saw an add a couple of years ago for an impressive-looking
>unit. Alas I can't remember the specs, but it was 500 and something
>pounds. But that doesn't mean a lot as I don't know whether it was
>top, bottom or middle of the range. They don't come cheap though.

I use rainwater on my plants. Works fine for me. When I was renting
and I did not have access to a rain-water tank I would stick a bucket
under one of the down pipes of the house I was renting and save the
water in 25 litre carboys (big plastic containers) and a 200 litre
plastic drum - all of these were carefully scrounged over the years
but I have seen the 200 litre drums at salvage yards. You can save a
lot of water this way, during a good rain storm we could collect many
litres. I had enough containers to last me through most of our

BTW If anyone in Adelaide would like some carboys they can have them.
Now that I have my own place with a rainwater tank I don't need them,
in fact they are a damn nuisance now! Some have lids others don't,
various sizes 25/20/15 litres. Email me if you want them and we can
arrange something!

-- Brett Lymn, Computer Systems Administrator, AWA Defence Industries
"It's fifteen hundred miles to Ankh-Morpork" he said. "We've got three
hundred and sixty three elephants, fifty carts of forage, the monsoon's
about to break and we're wearing ... we're wearing ... sort of things,
like glass, only dark... dark glass things on our eyes..."
- Terry Pratchett "Moving Pictures".