[Ethan25]

Quote: Originally Posted by CarolinaGirl So is the water gravity flowing back to the pond? the only suggestion I would make is tie the static K1 filter in the first tank to the PVC filter with a 4" line and instead of putting the pump between them, draw the water from the second filter with the pump and send it back to the pond. I am not so sure I like the idea of the valve in the bottom of the pond though. If you are keeping the pond running year round, it would not freeze anyway. In the pond it is an obstuction that koi can get injured on.

I don't know that I can run the water year round. It gets pretty cold here....we just got 8 inches of snow today! The problem is the second chamber. The way it works, it has an inlet at the top which has a spraybar, then 4 outlets and a lip. Here's a picture of it. I can't change this part as my wife doesn't want to waste this. We spent around $125 on it last spring, and she doesn't want it to go to waste. I planned on putting a possible airpump near it with airstones on the bottom to aerate the bacteria.

This is the inside of it. At the top of the picture on the left side is the 1 1/2 inch inlet with threading. THe bar across is a spraybar. I have baskets with bio-balls that fit in-between those rails, but I plan on taking it all out and putting pvc shavings in it (in some sort of netting). Then, the water exits via gravity out the four openings. You can see them in the second picture. What is the point of having the pump AFTER the bio? In order to not lose any gph?