Backyard Aquaponics
A place to discuss aquaponics

Hello, I'm new here to the forums, but I've been doing a lot of reading in here for a little over a month.

My duck pond is about 630 gallons (I think that's about 2300 liters) and I have 6 ducks and 2 geese, which equals a lot of poo. I made what I thought was a good biofilter and started it up. It did well. The water was on the murky side but overall it looked good and smelled clean. I was about to start flowing the water through the growbeds when one morning I woke up and the water was chocolate in appearance and I realized that the sludge had built up enough to have covered my entire filter.

Well now I'm back to the drawing board. I'm thinking I want to collect the sludge in a prefilter and was wondering if the one in this link would work for my purposes:
http://1.bp.blogspot.com/_kiwWdODqX6M/S ... ilter1.JPG

At first glance of that "pre-filter" my initial guess is !!!!!NO WHERE NEAR BIG ENOUGH!!!!! Yep that was me shouting.

Can you tell us more about your filter that got all sludged up?

You mention flowing the water grow grow beds, what sort of grow beds are you wanting to flow the water through?

If the grow beds happen to be flood and drain gravel beds, (provided you have enough of them) then I'd say, bring on the sludge water and the gravel beds will help to filter for you. However, I don't know the fish to duck conversion ratio so I'm not sure how much flood and drain gravel bed you would need to handle the output from each duck.

I like 5 gallons of flood and drain gravel bed to handle the output of each one pound fish. However, ducks do seem to poop a lot. Maybe you want 10 or 15 gallons of flood and drain gravel for each pound of bird pooping in your pond.

Otherwise, you might just want to install a swirl filter and drain off the sludge every day and use it to activate some high carbon compost.

This is a picture of the bottom of my filter it swirls:


Here's looking down the top. I'm using scrubbers for the filter medium then hardware cloth on top of that and the bricks hold the hardware cloth down:


I have the filter in a 50 gallon (190 liters?) trash bin. I'm having several problems which I'll be tweaking (I'm awful at understanding written directions until I've seen things in action). First is oxygen in the filter. I have blood worms growing in it with suggests I'm not getting nearly enough oxygen in there. This is an easy fix. And second I may not have enough filter medium which is why it stayed murky before it turned chocolate on me. Another easy fix.

As for the prefilter I was thinking that the one I posted was too small also. I would make it much bigger! I was just wondering if the design would work. Initially I was going to have just some leafy stuff growing next to the filters and use continuous flow, but I finally got my husband interested in the whole thing and we're thinking we might be able to pump up to the front of the house where I have sunlight so we can grow tomatoes and beans. I still had planned on continuous flow, but now I'm not too sure.

First thing I need to do is get the sludge thing taken care of.... right?

A large gravel bed system that drains thru a "wetland area" before returning to your pond. Something ornamental like Hydrainia's and Elephant ears and reeds etc. I would use a dirty water pump with a little recycle to swirl in the bottom of the pond. You could even grow a little duckweed in the wetland area as a treat for your ducks.

Oh that sounds really neat. Do you know where I might find pictures of what you're talking about so I can get an idea of how to set it up? Would it go through the wetland area before heading off to my grow beds, or on the way back? I grow a lot of vegies in my front yard and even though I come from a wet climate I would like to conserve water and put grow beds in that area. I had been thinking gravel beds. This summer we went 29 days without rain which was almost a record (I know that's nothing for you aussies, my husband is from Melbourne). The amount I had to water astounded me!

When I set the filter up I wasn't thinking properly so didn't realize exactly what sludge was and how much I was going to have. Therefore I didn't put a drain at the bottom for releasing the sludge. Do you think I could just modify my existing filter with a sludge drain? Or should I go ahead and make a prepump?

Modifying the current filter is probably a good idea. Put a fairly large pipe through with a valve so you can dump the heavier solids daily. Got a compost bin and lots of carbon cover material? I expect that sludge to stink and dumping it into big piles of leaves and covering with more leaves would probably be the best way to make good use of it without stinking up the place. (and next season you got some nice compost to spread around the dirt garden.)

As to using constructed wetlands. I don't really know much about it. However if you are planning to have gravel grow beds for growing your veggies, you probably don't want to use up all the nutrients in reed beds before sending the water to your veggies. You might just want to leave yourself space to add in a "wetland" bed either before or after your veggie beds if you find more water polishing is needed at either end. The veggie beds will probably be enough.

It's worse than I thought. I need to redesign the entire thing. I have A LOT of solids Way too much for the size of the current trash bin. I'm gonna drain and start from scratch. Hubby and I have been looking over some different designs in the forums and are contemplating which one to go with or modify for our uses.

I'm thinking about doing the following

viewtopic.php?p=197469#p197469

wetland: http://www.youtube.com/watch?v=eqeozOOe ... annel_page

I did some research and the ratio seems to be about 1lb of duck=5lb of fish.

http://www.extension.umn.edu/distributi ... D7671.html

Here is a good article on constructed wetlands but just google "constructed wetlands sewage treatment" and you'll get plenty of hits. If you do go this way, I would also suggest a simple hoop house to keep rain water out and extend the length of the season as bacteria will shut down when temps start to drop. Depending on what type of "wetlands" you decide on, you are looking at the same aerobic bacteria as AP or anerobic bacteria that operates your septic tank. There may also be a problem is mosquitoes.

Another type of water treatment you might want to consider, based on footprint size, is green water treatment- with a way to remove the finished sludge (basically wet compost soil at this point). You will also have this same issue with the constructed wetlands as the sludge will build up and need to be removed from time to time.

I don't know how much acreage you have to work with but have you thought about using catfish or carp to move the sludge around and a irrigation/trash pump, at the deep end of the pond and pumping the water to a small orchard? This is one of the projects that I have planned for the future. It would remove the silt on a regular basis and deposit it at the base of the trees. The catfish could be used as food or brood stock for AP- or the carp for decorative purposes. Except for the pumping, this is similar to concentrated food production in some third world countries. The water fowl actually splash enough to aerate the pond so the fish, if not stocked too densely have enough oxygen. The fish eat the excess bird food and keep the sludge from accumilating into anerobic dead zones. Based on the small size of your pond, you may have to enlarge it or reduce your flock though.