Aeration means adding oxygen to your water. This provides ideal conditions for “good” aerobic bacteria to grow in number. These “good” guys get to work reducing murkiness in your water in a number of ways. (i) They directly consume suspended decaying organics, which improves water clarity. (ii) Through their own metabolic processes, “good” bacteria also reduce nutrients in your water, such as nitrogen and phosphorus, which reduces how much food there is available for aquatic pests, e.g. algae, aquatic weeds, “bad” microbes etc. As these invasive populations plummet—through being outcompeted—your water will get clearer. (iii) “Good” bacteria also eat the sludge on the floor of your dam, which again reduces how much organic content there is in your waterbody. Sludge is fertliser for invasive pests, so tackling it also reduces how much algae or weed there is in your water.