1. Rules of thumb in aquaponicspH
Oxygen
Fish
Plants
Biofilter
System design

2. pH Balancing acids in the system pH and ammonia Adding base
KOH
Ca(OH)2
1kg of fish feed to ~0,25 kg of base
-pH or potential hydrogen
is the negative logaritmic measure of hydrogen ions
-best pH range for plants and bacteria is from 6.5~7.0
-unionized ammonia nitrogen is higly toxic at pH levels over 7.5
-system tends to be acidic because of nitrification process
Adding base
-3% of the daily feed ends up as ammonia-nitrogen in the water,
-1g of ammonia yields 4.42 g of nitrate and plus a small amount of cell mass - consumes 7.14 grams of alkalinity during nitrification.

3. Oxygen Safe ratio 1:1 Deep aeration Move water not air Removing solids
25% of feed becomes TSS
Radial flow clarifier/swirl separator
radial-flow settler 190 lpm/m2
Settling basins, drum filters
Proper tank design
-system uses 1kg of O2 per 1kg of fish feed
Deeper aeration, better oxygen absorption
Moving water is more effective
Removing solids – less oxygen needed
Separate mineralization of solids – adding back to system
Round tanks or at least rounded edges
cornell dual drain design, center outlet

4. Fish Fish stocking Feeding rates Constat feed input
Final weight kg/m3
Feeding rates
Constat feed input
Staggered production
20-30% harvest
Multiple fish size
Stocking depends on filtration system, oxygen levels and nitrate removal
Feeding rates depend on the size/maturity of fish
Staggered production- harvest every 6 weeks
Multiple fish size – harvest only the plate size fish

5. Plants Daily feeding rate LAI – leaf area index Visual evaluation
10-25 g/m2
LAI – leaf area index
LAI = leaf area / ground area, m2 / m2
LAI < 0.6 feed only 50% of daily feed
LAI > 1 feed 100% of daily feed
Visual evaluation
Coverage in %  % of daily
fish feed
Feeding rate depends on filtration and solids removal
We evaluate the LAI index and combine it with the visual evaluation
LAI 0.5 with 50% coverage – 25% of daily feed

6. Biofilter Flood and drain system Solids removal
No other filtration – 1:1 or 1:2 ratio
Solids removal
SSA(specific surface area)
kg TAN/day produced(0,3% of feed)
gTAN/m2/day removed
1m3 of fish tank to 1m3 of grow bed media
- 10kg fish – 1% - 3g of TAN/day – 300m2/m3 -1gTAN/m2 removed  0,9m3
- Typical hydroton(expanded clay) – 300m2

7. System design Keep it simple One pump Short pipelines Oversized pipes
Less chance of faliure
less power needed, less heating/cooling of water
Clogging prevention

8. Thank you for your attention
Matej Leskovec