Try this
Mix one part liquid dish soap with five parts water. (Different soaps need different ratios. Experiment.) The reason you can't drown out bugs with plain water is that the surface tension of water is high enough that it can't penetrate their ... the things they breath with. (What is that called in ants, anyway?) The soap breaks down the surface tension and drowns them. This was developed for use against "killer bees" in Texas. You might want to google on that to find exact recipes.
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