When did you clean the filter last? Make sure all your connections are still intact.

Are you sure it is dirt? It could be dead algae. Which I thought was dirt until I was informed otherwise. Is your pond lined? Is this a new pond this year? How long has your filter been running since last cleaned? Do you have any pics of your set up and pond?
Sorry for all of the questions but this info would be helpful. Just my two cents. Maybe someone else more knowledgeable will come along with an answer for you.

yes it could be dead algae. i set it up a month ago, and added some more filter material. i think i might have disturbed it when i did. the pond is lined with rocks all over. the pond is about 1200-1300 gallons with a 55 foot stream and 2 ft water fall (2700 gph pump)that we turn it on when we go out side. the filter feeds a 40 square ft bog/stream that runs all the time (1400 gph pump). i thought maybe it was to much water coming up through it. the pond is 2 years old. small bog and 2 foot water fall is this year and the creek 3 years old.i just keep adding :)

tmyers where are you in MI? i am in bay city

thx jeff

I am about 30 miles north of Grand Rapids in a tiny town called Pierson.
I am wondering if everything that may settle in your stream and waterfall is getting churned up again and again when you turn on your pump? As you said maybe it is too much flow all at once when it is turned on suddenly. Have you tried leaving it on all the time to see what happens. Maybe the 'dirt' would find somewhere else to settle and then you could get a better idea where it is coming from.
I have a small pond. It is about 600 gallons and I had the dead algae 'dirt' all over the bottom. I turned the pump off and used a wet/dry shop vac to clean it out. It worked great.
I doubled the size of my pond this spring and left out the rocks on the bottom this time and what a difference it has made. There is no where for the gunk to hide.
I built a skippy filter this time. At first start up the water quickly went cloudy and string algae set in. As my plants have started to grow and nature has taken it's course I now have crystal clear water. My pump and skippy run non stop 24/7.
I am in desperate need of more plants. I am going shopping today as a matter of fact. I fear as the temps rise so will the algae if I dont get more plants.
So enough about me...lol I am thinking as we both said above maybe turning on you pump is churning everything up. I am thinking I would leave the pump on 24/7 to see what happens? Can you regulate the flow coming from the pump? Slow it down maybe? It's worth a try.
Do you have any pics?

Here is a link that might be useful: {{gwi:205889}}

my pump with the skippy is running all the time. i think when i messed with the skippy it stired up the dirt and went in the small creek. all the dirt is on the rocks before the first water fall, after that its not to bad. we turn on the big 55 ft creek when we are outside or when we are home during the day. i'll have to try the shop vac again, or i might try to rig a well pump and filter. i'll see how that works.
when i first got my skippy running the water was clear and the algae was all over everything. with the temps rising and adding some bacteria, the algae is going but now the water is kind of foggy/dirty. i hope in time it will clear up.

thx for the suggestions