Beware of glossy websites - In my experience, the fancier they are, the more expensive the product - which is perhaps obviated by their failure to include any prices.
Becki, I recall suggesting Andrews Water as an option last week and there is always mention of the other main companies on this forum: Omnipole, Cleantech, Wintecs, Stream, to name a few.
These are tried and trusted companies, who mostly will do all to show you the ropes and give crucial advice.
All that glitters....