Who needs clean ponds??

Every day I change the pond water (its actually an up - cycled sand pit so not huge) I change it because Ducks need clean water to keep their bills clean properly. Normally Ido it at night do its drained and dry by morning to refill - the pond sits in the depression thats filled with water here. I forgot last night so did it this morning and the ducks loved it! Maybe I will do that every day=D