Adam Cohen put together an information session and demonstration of aquaponics to a group of about 20 people this afternoon. He gave us lots of great info about planning and starting a system, then we got to tour his setup in his classroom. (he is a high school teacher) He is going to be placing more emphasis on bringing folks together who are interested in aquaponics and sustainable living, and will be updating his blog more often as well. My notes from his presentation and Q/A are below. This was a great experience, I learned a lot!
- bioponics = uses worms or BSF juice instead of fish
- gardenpool.org
- prefers slow fill / fast drain over fast fill / slow drain
- prefers CHOP layout = constant height one pump (water level in fish tank stays constant, uses sump tank below grow bed, grow bed is below fish tank) – pump always on, tank water flows freely (not through pump), most graceful to mechanical failure
- rule of thumb #1 = 1 lb of fish to 3 gal of fish tank
- rule of thumb #2 = 2 gal of grow bed to 1 gal of fish tank
- 3ppm of ammonia = dangerous
- 5ppm of nitrite = dangerous
- 600ppm of nitrate is getting dangerous (this is plant nutrient source)
- egg whites can be used as water clarifier
- Adam’s barrel system fills in 12 minutes, empties in 3 minutes
- want at least 2 water changes of fish tank per hour
- for 100 gallon+ systems in Texas, recommends talapia from March to October, catfish in the winter
- Overton Fishery is closest local source of fish stock
- Talapia types:
- Mozambique (mossambicus) – smallest, slowest growing, fast breeding, die at temperature below 70F, only type legal in TX w/o permit
- Blue (aureus) – tolerate colder temperatures (55F), considered ‘exotic’ by TX law, requires $250 permit and local inspection, hybrid (won’t breed)
- Nile (niloticus) – ?same as blue, or no info
- hornorum – more desirable, larger, faster growing, but forbiden in T
- Don’t plant mint in your growbed unless it is all you want in that bed (invasive)
- If you smell something odd, them something is going wrong: water chemistry
- Prawns don’t mind varying water levels, good to put them in a sump tank
- plants do best with pH of 5.5 to 6.0
- fish do best around 7.5 pH
- Adam recommends rock size 1-1/2″ to 2″
- Test if limestone by placing sample of rock in vinegar – if bubbles, then you have some limestone and don’t use
- recommends DVD’s and forums at aquaponics.net.au
- recommends diyaquaponics.com forums
