We recently had a new filter system installed on our pond approx. 4 weeks ago (oase Biosmart 30000 and 8500 pump). which runs out onto a watercourse about 6' long to a fall off a slate. Drop to the pond at top water level I would think is 12" - 16". The ponds is about 1100/1200 gals. 4'6" at its deepest to varying levels to the shallowest about 1'. Area is about 14'/15' x 9'/10'. It is in direct sunlight just about all day, until around 7pmish We noticed last week that overnight the pond may have dropped a good 1" and maybe sometimes less, a night. I know the weather has been hot and sunny and at times humid. We decided to bypass the fall so we have the 3" hose to fit on the outlet/discharge pipe of the filter, so last Monday we did this. We noticed that the drop now was roughly 1" to 1 1/4" over a 5 day period. This varied each day some days no change and then say the next day maybe 1/4" difference and so on. We have now topped up the pond a good 3" in total about. What I am asking is if the fall is running is it normal to expect a drop of 1" a day due to evaporation. The filter system we had before really did not do the job and the flow of the water onto the watercourse and fall was not as powerfull as to what we have now. Also I now have sort of dirty water (sort of muddish colour) this is after have a pea green water and the biosmart totally cleared this up and we had beautiful clear water, until we let the water drop last week then it turned dirty. I cleaned the filter out today so I hope this clears the water.