I love my Grandmother dearly, but it gets very tedious having to clean her 40 gallon fish pond once a month. We'd like to do something to keep it clear all year round. She has 4 goldfish in it, they've over wintered the last few winters so they've grown from pinky sized goldfish to now almost the size of your hand goldfish. The pond is in the sun for the most part of the day. We do have a pump in it with a filter system, though it's about 4 yrs old now and may need replaced. The algae is so out of control. Every month the water turns so green that you can no longer see the fish and it sticks to the sides of the hard plastic pond. The pond is for sure 40 gallons, so if ANYONE could give me some info on how to keep it clear I would appreciate it!