Notes on aquaponics
02 Feb 2019How aquaponics works (in a tiny nutshell)
- fish effluence → clarifier/settler for anaerobic mineralization → biofilter for nitrification (aerobic NH3 + H2O → NO2 → NO3) → grow bed → sump → rearing tank
- 0.5–1 lb fish ←→1 gal water ←→0.5–1 sqft grow bed
- recirculating/closed-loop/media culture aquaponics vs. nutrient film technique vs. deep-water raft aquaponics
- system inputs: fish feed, iron, magnesium
Notes from Aquaponic Gardening by Sylvia Bernstein
- The Aquaponic Gardening Community
- “Much of the greenhouse tomato, basil and lettuce production in North America today is done using hydroponic growing techniques…”
Lighting
- needs to cover blue/red spectrum
- fluorescent lighting with T5 bulbs
- broad plant lighting spectrum
- low power consumers, low heat
- only reach through 18in (45cm) of plant canopy
- need to replace every 6mo
- high-intensity discharge (HID) lighting
- metal halide (MH) for vegetative growth or high-pressure sodium (HPS) for mature/productive stage of fruiting plant
- LED lighting
- no heat, very low power consumption -> never replace bulbs
- asdf
Grow beds and fish tanks
- media bed better than NFT or deep-water culture (raft/DWC)
- basic flood and drain: simplest design, for 1:1 grow bed to fish tank volume
- add sump tank (CHIFT PIST/CHOP)
- CHOP2: along with CHOP, allows 2-3:1 grow bed to fish tank ratio
- Barrel-ponics
- hybrid system
- grow bed
- industry standard >= 12in (30cm) deep for plant roots and complete filtration
- media guard
- fish tank
-
= 250gal (1000L) better for stability
- need >= 50gal (200L) to raise fish to plate size, 12in (30cm)
-
Plumbing
- pump
- flow rate
- head pressure, lift
- pipes
- usually polyvinyl chloride (PVC) or chlorinated polyvinyl chloride (CPVC)
- half-inch (12mm) inner diameter PVC
- alt to PVC: high-density polyethylene (HDPE)
- pipe attachment
- marine-grade silicone
- Uniseals
- bulkhead fitting
- pump timer
- mechanical or electronic timer
- no-timer systems include autosiphons, flush valve systems
- flood once per hour (15min on, 45min off)
- flow entire folume of fish tank throw grow bed(s) every hour; e.g. 100gal tank with 15min on/hr needs a 400gph (gallon-per-hour) pump
- Construction of automatic bell siphons
Grow media
- 3 filtering functions
- mechanical solid removal
- mineralizzation (solids breakdown, return to water)
- biofiltration
- grow media purposes
- structural
- biofilter for solid waste
- home for worms
- air/water exchange
- temperature moderation
- media
- cannot change water pH
- cannot decompose
- 12-18mm in diameter
- should be porous
- lightweight expanded clay aggregate (LECA/Hydroton), lava rock, expanded shale, gravel
- gravel weighs 105lb/ft3 (1682kg/m3)
Water
- water weighs 8lb/gal (1kg/L)
- municipal water supply usually contains chlorine or chloramines, must be off-gassed
- heating
- aquarium heater
- swimming pool heater for large tank; e.g. with titanium heating element
- hydronic, radiant, or “in-floor” heating
- dissolved oxygen
- break surface tension of fish tank
- aeration device for supplemental oxygenation
- must be >3ppm, preferably >6ppm
- pH
- API Freshwater Master Test Kit (weekly) or digital pH meter
- pH buffering agent
- to raise pH: calcium hydroxide (hydrated lime), calcium carbonate (agricultural lime) with potassium carbonate, bicarbonate, potassium hydroxide (pearlash/potash)
- to lower pH: hydroponic acids (nitric, phosphoric), vinegar; do not use citric acid
- fish 6.5 - 8.0, plants 5.0 - 7.0, red words and bacteria 6.0 - 8.0
- must be 6.4 - 7.6, optimally 6.8-7.0
- tends to rise during cycling
Fish
- 1lb (500g) fish for every 5-10gal (20-40L) for home media-based system
- tilapia, goldfish, catfish, koi
- shrimp, barramundi, pacu, perch, trout, oscars, freshwater lobster
- keep temperature within 2C in 24hr period
- feed 5min worth of food every hour
- adult fish eat 1% of body weight per day, juvenile 7%
- homegrown feed
- duckweed
- earthworms, sludge worms, bloodworms, composting red worms (red wrigglers)
- black soldier fly larvae (BSF); check out BioPod
Plants
- cannot grow plants that prefer too acidic or basic
- acidic soil: blueberries azaleas
- basic soil: chrysanthemums, calendula, zinnias
- oxygen, hydrogen, carbon from air (O2, CO2) and water (H2O)
- macronutrients: calcium, nitrogen, magnesium, phosphorus, potassium, sulfur
- micronutrients: boron, copper, iron, manganese, molybdenum, zinc, aluminum
- plant temperature depends on water temperature
Bacteria and worms
- nitrifying bacteria: nitrosomonas and nitrospira
- aerobic autotrophs
- efficient at converting ammonica and nitrites
- nitrosomonas convert ammonia to nitrites
- nitrospira convert nitrites to nitrates
- nitrosomonas NH4+ + 1.5O2 -> NO2- + 2H+ + H2O + 84kcal/mol of ammonia
- nitrospira NO2- + 0.5O2 -> NO3- + 17.8 kcal/mol of nitrite
- overall NH4+ + 2O2 -> NO3- + 2H+ + H2O + energy
- optimal temperature 77-86F (25-30C)
- maintain pH 6.0 - 8.5; nitrosomonas optimal 7.8 - 8.0, nitrospira 7.3-7.5
- composting red worms for solid waste
- worm castings or vermicompost
TODO
- Cycling
- System maintenance
- Appendices
Good intros
- Aquaponiacs: Introduction to Aquaponics
More readings
- Aquaponic Gardening: A Step-By-Step Guide to Raising Vegetables and Fish Together by Sylvia Bernstein
- Aquaponics by Williams Walsworth
- The Spotless Garden
Forums and threads
- /r/aquaponics
- https://news.ycombinator.com/item?id=4691744
Other links
Sensors
Random notes
- tilapia, perch, trout, hybrid striped bass, catfish, koi
- shrimp, crayfish, shellfish
- ducks, chickens, quail
- bees
- freshwater species
- http://www.eatthis.com/10-superfoods-healthier-than-kale
- https://en.wikipedia.org/wiki/Crop_tolerance_to_seawater
Insects
- Farm 432 for black soldier fly larvae
Businesses
- Primer on aquaponics in the US
- AutoMicroFarm
- Growing Power vertical farms (Milwaukee)