Stanna, have you considered purchasing a stainless steel enema can? They are somewhat expensive, but very easy to keep clean and last a lifetime.
You do have to separately purchase the tubing and rectal tube which have a finite life and must be periodically changed. If you get either clear plastic tubing or amber surgical tubing it's fairly easy to see if mold is forming, and if it is you can try to clean it or just discard and replace it.
If you purchase an enema can I suggest getting a 2 litre size, not the 1.5.