and piece of gas line (or at least that's what I use)
Buy the hand pump to get the fitting

It’s funny to see everyone’s adaptations to solve the same problem lol

we also use a garden sprayer. Went to Home Depot and started opening boxes to find a sprayer that had the biggest pickup hose inside. Many of the sprayers have small pick up hoses (1/8”). We found something bigger like 1/4”.

the exterior tube was fine to use so we simply cut off the sprayer end and fit a small brass ball valveon the end. After that we connected another piece of hose to an adapter fitting. All said and done it was $50. The sprayer we picked was one of the nicer ones 35$.