Question
Hi i am a newbe in ponds this year is our first . we have a 270 gallon pond with 2 filters one is 300gph Spring filter and the other is 330gph and pulls water out into tank and comes back in through a double spitter. We have 4 submergable plant bags in the process of growing and some top water floating plants. but i noticed the water was looking a tad murly and had some algea so i added some algacide and now around the rim of the plastic preformed pond is a white foam looking substance. Is it because i did algacide?? Also there has been a water temp. change as it has been chilly past few days so fish are not eating. i have 4 baby koi. So my main concern is the water color and the foam .. best i can describe it. it isnt on water top just around the edges and surrounds ther. and anything floating on surface like solar light or artificial lillys  is a very thin line of " white foam"

Answer
Hello Shannon!
I am not sure, but from your description of things it seems what you have are a couple of pumps, not filters.
I think at this point it would be best to test the water thoroughly. You can either do this yourself with an inexpensive pond water test kit (for ammonia, nitrite and pH).
Adjust these three values as needed.
Also, be sure to figure the volume of the pond exactly, because you never want to overdose algaecide.
Once the pH, nitrite and ammonia levels are under control, you can add beneficial bacteria and they will eat the nutrients in that are causing the foam.