There are a wide variety of options for removing muck from the bottom of your pond. The best one for your particular situation depends, of course, on the size of your pond, the volume of muck you’re clearing out, your budget, etc. Whichever method you choose, make sure your pond filter is ready to go afterwards, with a good bacterial load and effective filtration for tiny particles that have been disturbed during the removal process.
For small ponds with a smallish load of thick or solid debris, a muck shovel and some sweat might be a good option, but for more complete cleaning, you’ll probably want to go with a siphon or a powered pond vac. The pond vac is the most expensive option, of course, but it also offers the least physical effort as well as lowest impact on your pond’s ecosystem. It gently sucks up the water & slime, runs it through a fine filter (muslin, for example) and diverts the water so it can be added back to the pond. The advantage here is that you won’t have to add tap water to top your pond off afterwards, which can negatively affect your water chemistry. Obviously, this isn’t the best option if your muck is primarily composed of partially decomposed leaves and other very large particles. If you have a very large pond and the muck is plentiful, the most effective approach will be to hire a professional with a powerful, commercial grade pond pump.
