A good way to deal with solids buildup in aquaponics is the use of worms, which liquefy the solid organic matter so that it can be utilized by the plants and/or other animals in the system. for a worm-only growing method, please see vermiponics .. The reason why those worms crawl from the soil to their death on the sidewalk is not because of the water, but because the water has forced the oxygen out of the soil. in aquaponics, not only does the flood and drain action pull oxygen into the grow bed media, but the water that is circulating throughout the system is highly oxygenated.. Another great way to use compost worms is to add them to an aquaponics system. this way you can kill several birds with one stone :-) add worms to the medium of an aquaponics grow bed and they will dive into it out of sight within a minute or two to escape from the light..
