If the water is murky and a brown or tan-ish colour, sediment particles are likely suspended within the water column. This often happens after a large rain event, so shoreline areas should be inspected to identify places of erosion where sediment has been entering the water. Ideally, this sediment input should be addressed and minimized, as stormwater runoff often carries nutrients too.
In some cases, murky water can also be due to an algal bloom as algae is not always green. Some algae species are actually red, brown, or golden, and can bloom at various times of the year. A murky pond could also be a sign that water levels in the waterbody are too low. A pond survey every 3-5 years are the best way to determine if a pond is filling in with sediment, and can indicate when it is necessary to conduct dredging or bioaugmentation.