Hey DL,
Yeah my pond is over 65 years old and has a LOT of muck in it and it has not been disturbed in a long time.
That sulfurous smell that finds its way around ponds is a common byproduct of a pond that is not aerated.
Non-aerated ponds stratify (layers in the pond have distinguished temperature differences) in the summer and winter, locking the bottom layer of water away for months. With no circulation, the oxygen is quickly used up down there, resulting in an anaerobic (functioning without oxygen) digestion process that is loosely equivalent to that of a cow’s stomach. Slow-moving anaerobic bacteria on the bottom use enzymes to ferment and digest the muck on the bottom. These bacteria produce waste products including carbon dioxide and hydrogen sulfide (rotten egg smell).
Most of the year, an un-aerated pond will smell fine because this buildup of nasty gasses stays locked away on the bottom. It is when the pond turns over (Spring/Fall temperature shift, strong weather event, etc.) that the foul-smelling gasses are released. Surprisingly, the foul smell is the least of the pond’s problems at this point. The release of this gas also signals that the inhospitable water that was stuck underneath has now mixed into the upper part where your fish are living. Wacky pH shifts, dissolved oxygen crashes, and algae blooms are a few of the byproducts of turnover, all of which have fish-kill potential.
The solution? Aerate like it’s your job! An Aeration System will keep the pond in a permanent state of motion, continuously venting gasses and providing oxygen to the bottom sediments. This allows the aerobic (good, oxygen loving) bacteria in the pond to inhabit the bottom sediments and work away at that ugly muck layer. Aerobic bacteria work similarly to plants in that that they use up the bad gasses and muck, and give off a little oxygen in return while working much more quickly than their anaerobic (cow’s stomach) counterparts. I have been supplementing these bacteria with MuckAway bacteria that will accelerate the decomposition process. Remember, keep that pond moving to keep that pond healthy and odor free! Good Luck!!
