I use a disposable enema container, and reuse it very many times. Obviously dump out the solution and wash out the container before you use it. I like the way it crunches up, which saves space and it holds twice the amount of a syringe. Good luck.
That's a lot of water! I was told to drink juices that are high in natural sugar, such as prune and grapes and Apple. I'm not a great fan of juice. As my output is thick I am constantly irrigating. Always looking for suggestions.