Algae is always an issue for a pond owner. Mechanical elimination is always an option for a pond owner. However, for a small pond like yours, I would not go through the trouble or expense. One thing to remember is that algae is at the bottom of the food chain when it comes to plant life. Depending on your region you can still purchase pond plants or water lilies. I would suggest adding a few pond plants to your pond. The plants will use up the nutrients in the water first. Chemical solutions to rid algae are only a quick fix and the algae will return.