I'm new to the forum and relatively new to ponds. I inherited a large pond (8'x44') on moving into a new house, and have a bunch of questions not surprisingly..
Attached is a plan, and two images to give you the idea. My plan is to vacuum as much of the visible algae & debris out (done), plant out the 'bog' or shallow area and start an algaefix treatment. I'm only stocking with comet goldfish for now. The pond was emptied, cleaned and refilled last summer.
My core question is how to best use the waterfall for a mechanical and biological filter. Should I just add a large mesh bag of lava rock down there for example? Right now it's just a 4 foot deep (by 3x3 ft) lined hole (see diagram) - feels like this was designed to be a filter system with the right media..
..... feels like this was designed to be a filter system with the right media..
Looks like it to me as well. Maybe one of the guys with aquaculture setups can help you out with suggestions. Have you checked into any of the Koi Pond forums? I suspect your setup is routine for them and they can probably offer good advice as well.
With goldfish, (assuming a clay bottom pond), expect to pump VERY muddy water after the first spawn. Goldfish will root around heavily on the pond bottom. If the entire pond is lined, Koi or goldfish will eat much of the algae.....after eating all the plants they can in your bog filter.....
There should be no need for a filter media with all the rock substrate already there for growing beneficial bacteria.
If you mix Koi in with some larger-mouthed game fish, the Koi wont be able to raise offspring to maturity. If you stock only goldfish, expect a murky mess, and eventually they will go "native" to plain colors like brown and black as their brighter and more visible brethren are consumed by predators.
On the other hand, the Koi will get enormous. Mine are surprisingly larger than I expected them to get. With only 4 in a large pond, there is plenty for them to eat and they don't stir things up too badly.