Himalayan salt is the one to use for cleansing and flushing the colon. This is by far the best salt available right now. It contains up to 84 elements and its of a pink colour. You can buy it in the U.K from SULIS!
Yes you have to balance the water with REAL SALT not toxic table salt ! It works out 1/4 tsp for every litre of water drank. Refer yourself to the work of Dr Fereydoon Batmanghelidj