I know red worms are great for media bed systems. Has anyone used them in their DWC beds? We’re exploring this option to expedite the breakdown process of debris that has accumulated in our beds.
@victoryaquaponics Can you share any input here?
Any insight is appreciated!
Cori Byrge
Communications Director
At Fontys University, we have a small setup of 60L Fish tank. We use the system for student projects and small scale research.
We introduced compost worms (tiger worms) in the flood and drain beds. The amazing thing happed, the worms ended up in the whole system, also in the DWC pipe. The worms propagate in the system but that goes very slowly. I think that a lot of the small worms end up in the fish tank.
My experience is that the breaking down of the sludge is not fast enough with worms. Maybe with the use of red worms it goes faster, but I doubt it.
1. Worm Species Selection:
- Tiger worms (Eisenia fetida) are excellent for breaking down organic waste, but they might not thrive as well in aquatic systems or in deeper water environments, such as the DWC (Deep Water Culture) pipes. They prefer oxygen-rich, moist environments, but full submersion may not be ideal for them.
- Red worms (Lumbricus rubellus), like tiger worms, are also surface-dwelling compost worms, and their performance may not differ much.
I’m thinking of introducing fresh water shrimps in the system. Shrimps are more suitable in aquatic systems.
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Thank you for the reply. We are looking to doing a trial at scale (1000’s of red worms).
Shrimps will not work in DWC’s. The simply eat on the plant roots, effectively killing your yields.
Do you have experience with shrimp? We are thinking of testing with small shrimp.
I’ve learned that shrimp only eat dead material. Therefore, shrimp would help with growth because unhealthy roots would be eaten. I am very interested in your results.
Yup we use them (red worms). They thrive in every part of the system as long as there is plenty of oxygen in the water. We haven’t had any problems that I could attribute to the build up of solids in our beds, and we find very few of them in the DWC. They seem to use our flood and drain media as a refuge.
We believe they also help to make iron available to the plants, which someone had told us at an AA conference. The introduction of them wasn’t deliberate though, and I’m sure we couldn’t get rid of them if we tried.
We now also have water snails, which I had long been fearing could move in. Luckily their numbers are staying very low, and they all seem to have very soft and delicate shells which I think limits them. A few goldfish in our DWC tanks keeps their numbers down (another animal that found its way into that part of the system on its own by eggs circulating through the sump pump). Goldfish can keep solids off of the bottom too, but you only want one or two or they will get hungry enough to learn to eat roots. Many of the worms we find anywhere are too big for a goldfish to eat.
I’d focus on better solid separation. Something that seems to work for us is Swiss chard in DWC trays close to the water inlet and spaced throughout the system, with their roots collecting solids and growing indeterminately as the plant above is harvested over time. That can really help filter the suspended solids as long as they are not moved around and disrupted. If its that big a problem I’d use clarifying filter media in my ‘clarifier tank’ (as defined by Rakocy). We just use orchard netting.
I wouldn’t worry about solids settled on the bottom of DWC unless it was more than 1/4" thick. We just had our system looked at by the current UNH professor who took over the school’s Aquapoincs project, who is doing an analysis of our bacteria. Her impression of an area of our system where we had 6 to 10 inches of very old settled solids was that it wasn’t anaerobic. Still waiting on the results from her samples though. The important thing is to keep suspended solids out of the DWC.