If algae is bothering you, a hand held skimmer net used for pools can work to manually remove what ever you can reach. I use a leaf rake, with the long flexible tines to remove string algae from my small patio pond. It works great!

Remove compost bins, burn piles, brush piles and pet/animal droppings that are up slope from your pond. Rain fall and melting snow can carry nutrients from these sources into your pond.

What about putting pesticides in my pond? Wait on that. A one time use might be acceptable, but no pesticide is safe to use.

“I heard that dyes might improve my pond”. You might want to rethink a “tidy bowl” blue pond. Golf courses tint their ponds because of all the fertilizers and pesticide that go into these. There is a reason no one swims or eats fish out of ponds like that! Yuck!!