Now in a normal aquaponics system, provided it is properly designed, the gravel doesn’t get clogged up and it doesn’t need re-washing.
However, Duckaponics is a different situation. Or should I say I didn’t design my duckaponics right. Now you get to learn from my mistakes.
1st, my duck tank is fairly large and I don’t think the grow bed was really large enough to filter for it in the first place.
2nd, the duck bed got partially filled with wood chips on one end when it was first set up and I didn’t have enough gravel, this has been slowly breaking down into muck.
3rd, I think a duck bed probably needs to be done with larger gravel to help keep from clogging.
4th, having it right on the ground where the chickens can easily scratch dirt and mulch into the bed means the duck bed clogged up very quickly!!!
I’m not quite sure what to do about #4 since having the bed right on the ground (and it’s more like duck river/stream than a grow bed) is wonderful for the birds since it gives them shallow water to play in (the ducklings can’t climb up to the big tank easily.)
Anyway, I’m in the process of upgrading the duckaponics a bit. The old water tanks have been taken for use as rain water tanks so I don’t have them as settling tanks before the duck tank anymore so I’ve built a new small grow bed that is set up above the duck tank and the pump floods it and it siphons into the duck tank which still flows out to the far end of the duckriver bed. Once I have finished washing gravel for that new bed (which should be a great place to grow plants for the ducks/chickens to eat) I’ll look into mucking out the mud from the pump end of the big duck bed. I need to add some more filtration and perhaps some way to easily pull and clean some net filters down near the pump. I’ll probably try to block the ducks/chickens further way from the pump end so I can get more plants going and keep the filtration cleaner on that end.