Save-a-Flush - toilet volume reducer
The Save-a-Flush bag contains a biodegradable polymer which swells on contact with water, plus a little sand to provide some weight. Simply pop it into your cistern, and let it sit there displacing a litre of water every time you flush.
And when it’s time to replace, you can empty the contents of the bag on your garden (the polymer will aid water retention in the soil) and the bag can be recycled
http://stwater.savewatersavemoney.co...-displacer/247
You can order up to 4. Free to Canada