Money Tree -Flies

My indoor money tree seems to have a lot of tiny flies around the soil, can any one recommend how to get rid of them?

There very tiny with sort of a blue tint to the wing.

 

My knowledge on it isn't extensive but I think they're called sand flies, usually happen when you have untreated soil with a plant. You can do what I did, which was spray the soil with fly spray, or change the soil with a treated one. Probably best not to overwater in the interim though, the moistness can mean once those flies mature they'll use the same soil for their offspring.

Probably better ways of dealing with it but that's what I did!

 

They are called "fungus gnats" here is a link to tell you all about them,
http://www.bbc.co.uk/gardening/advice/pests_and_diseases/nonflash_index.shtml?black_fungus_gnats