Any suggestions on how to keep your duck pond clean? How often do you change out the water, do you use a filtration system? Here's a pic of our "lap pool" my husband put in a shower drain at one end then a plumbers pipe that went out the back of the pen with a valve/stopper to drain the pool. This is after it was filled, it is really dirty now. Has any one put in a fountain to keep misquitos away, I know ducks eat them but misquitos love me and let me know it.