Justin wrote:
Thanks for the responses!

Whereas if I do use Muriate of potash, it's about AU$6.00
for approx 2kg which should last a couple of years, I'm just worried
about the chlorine in it...

As mentioned elsewhere, it's chloriDe not chloriNe - it's about as inert
an ion as one can get - "Mutiate of potash" is Potassium chloride, the
potassium equivalent of table salt.

The only concern is eventual accumulation of chloride salts in the tank,
but you'll be dosing at so low a level that it shouldn't be a concern if
you have any sort of water change regime at all.

Also, sourcing KH2PO4 and KNO3 is proving difficult in australia...

Don't know about the phosphate, but the KNO3 is also sometimes sold as
stump remover. Don't know about the legality of it in Oz - it might
potentially be regulated as bomb making material.

I
went to a chemist last night and got excited when the had the Fleet
product, but it was lemon ginger flavour... Don't think the fish would
like that too much... Will keep on looking...

Hmm ... I'm only familar with Fleet Enema - I'm unsure why one would
want lemon ginger flavouring in an enema.