In the last 2 weeks I changed over my established gravel to playsand - 2.99 for a BIG bag.
Took out all the plants and rocks
I took out half the gravel
Moved the rest of the gravel to one side
Put a load of sand in (unwashed) and let it settle
- Cos it wasn't washed took about 24hrs to clear...
About a week later I removed the other half of the gravel and added the rest of the sand (washed this time)
-- to wash I put it in a big bucket and ran a tap into it for about 30 mins in the bath - Sturring it every now and again
Do this about 48hr's (or more) before you add it to your tank and the chlorine in the water will be removed naturally. - The sand cleared pretty quickly.
Cleaning the tank it really easy - Just hover the vacuum over the sand and it all comes up.
If you are replaceing gravel like me - Keep a load of it and put it in a stocking (pantyhose?) and leave it in the tank for as long as you can bear to look at it (mines gonna stay there for 2 weeks.