You could try boiling the water first.....

You could let the water sit, uncovered, for a day to evaporate the chlorine; or run it through a Brita filter (maybe I've been watching the Biggest Loser too much). Make sure the temperature stays above 50 deg.F. That seems to be the minimum for most tropicals.

Sorry, folks, but none of those methods will remove calcium. The only filter systems that will remove calcium is reverse osmosis (available commercially) or de-ionization (expensive, and hard to find). Mixing in 1/2 teaspoon of vinegar per gallon of water will alleviate many of the problems that excess calcium causes. I would also check the sodium levels in the water--high sodium often goes with high calcium, and does even more damage to most plants. RO is again the only practical means of removing sodium.

I checked the sodium levels a while ago and it wasn't a problem because I have well water and don't use my water softener. The vinegar sounds like a good idea, I'll give that a shot. Thanks for the help!

What plants will be suitable to grow in my new conservatory, it's south facing and therefore will get pretty hot soon. thanks.

Rosie, Unless you already have, you may want to open your own question on this. That will get you the widest pool of potential responders, and help conserve the GoY servers!