Just be aware that a large percentage of the people who claim they take ridiculously large volume enemas (2 gallons or more) are bullshitters. The average colon can expand to a diameter of about 3 inches and is about 5 feet long. That average colon can hold about 7 quarts (14.5 pounds) of water, if you can keep from expelling it.
You cannot stretch your colon to larger sizes by taking repeated large volume enemas, no matter what people claim on this site. I gave myself my first enema when I was 8 years old. I am about to be 72, so that is 64 years of enemas. During my life, I have taken an uncountable number of enemas, some large volume some average volume. I have forced myself to take numerous large volume enemas, at least a thousand, probably closer to two thousand. So, after all that, if anyone should have stretched his colon, it would certainly be me. Guess what, I can still only take the same volume enema I could years ago when I took my first large volume enema. The point is that your colon is not like a rubber balloon that can be stretched out of shape until it is deformed so it can hold more water, and anyone who tells you that is full of shit (pun intended).
The way this usually goes is that there will be a bunch of indignant responses, usually falling into three groups.
One will just tell me I don't know what I am talking about and question my credentials to make these claims.
A second will offer the tired old response that everyone is different, and while that may be true, there are still certain realities that apply to everyone, namely, your colon does NOT stretch like a balloon.
The third group will respond with stories of how they took enema after enema and gradually increased the volume, but that is the result of cleaning the colon so there is room for more enema water, as well as will power, as the person gets used to the discomfort.
Just be happy with what you can take, after all it is about what gives you pleasure, so if your limit is 3 quarts and it feels good, then fine. If you don't take more than 2 quarts, then that is perfect for you. Volume is not an ego contest among playground children, ("I can take more enema than you, nah, nah, nah!")