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.)
> 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...
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.
Happy growing,
Peter
-when I win the lottery...