Official nutrient supplements

f/2 medium

We're using Micro Algae Grow from Florida Aqua Farms: label1, label2, label3

f/2 recipe at the National Center for Marine Algae and Microbiota

f/2 recipe at cyanosite

F/2 recipe at the UTEX Culture Collection of Algae

f/2 recipe at Rutgers

f/2 medium contains 75 mg NaNO3 (MW 85) per liter_{, or 75*14/85 = 12.35 mg N/liter. (Additional N in the vitamin and trace metal solutions are negligible.)}

f/2 medium also contains 5 mg/liter of NaH₂PO₄.H₂O (MW 138), or 5*31/138 = 1.12 mg/liter P. (Additional P in the vitamin solution is negligible.)

Total dry mass in f/2 medium is approximately 105 mg/liter. If the dry Micro Algae Grow was labeled as a plant fertilizer, its N-P-K rating would be 11.8-2.5-0

Recommended dose of Micro Algae Grow for f/2 medium is 40 drops, or 1/4 tsp, or 1.45 ml per gallon. That works out to 383 ul per liter. Or 76.6 ul in 200ml of salt water

L1 medium

Modified version of the f/2 medium with a wider range of mineral salts; recommended by our dino supplier

L1 recipe at the National Center for Marine Algae and Microbiota

L1 recipe at cyanosite

L1 recipe at the Scandinavian Culture Collection of Algae and Protozoa

L1 medium has a wider range of mineral salts, in trace amounts (including about a microgram of K). Elemental composition of N and P is virtually identical as for f/2.

DIY nutrient supplements

Miracle-Gro Liquid All Purpose Plant Food 8-7-6

Label Label at www.scotts.ca

Recommended use:

Indoor 10-20 drops/l if feeding every time
1/2 capful per l if feeding every 2-4 wks

Miracle-Gro Water Soluble All Purpose Plant Food 24-8-16

Label Label at www.scotts.ca

Metals composition from CDFA Fertilizer Product Database:

• B 0.02%
• Cu 0.07%
• Fe 0.15%
• Mn 0.05%
• Zn 0.06%
• Mo  0.0005 ppm (?)

Recommended use:

Outdoor 1 tbsp per gallon (3.9 ml/l)
Indoor 1 tsp per gallon (1.3 ml/l)
Apply every 1-2 wks

Alaska Fish Fertilizer 5-1-1

Label1, label2, label3, label4

Metals composition from CDFA Fertilizer Product Database:

• As  4.2 ppm
• Co  0.4 ppm
• Cu 7.8 ppm
• Ni  2 ppm

Recommended use:

Outdoor 2-3 tbsp per gallon (7.8-11.7 ml/l)
Indoor 1-2 tsp per quart (5.2-10.4 ml/l)
Apply every 3 wks

Equivalence calculations

Since the official f/2 and L1 media are primarily nitrate by weight (75mg sodium nitrate for 105mg total dry weight), we would like to match the starting nitrogen concentration with the plant fertilizers for our DIY growth experiments. According to feedback from the Miracle-Gro help line, N-P-K composition for fertilizers is given in % of total weight, even for liquid fertilizers. So if we know the density of the liquid, we can calculate the N content.

We will start by making stock solutions for all three fertilizers, using the recommended dilution listed on the label. If we go by recommended use as a fertilizer for indoor plants, feeding every 3 weeks (i.e., doubling the recommended amount for dry Miracle-Gro "every 1-2 weeks"), this averages to:

• Liquid Miracle-Gro 8-7-6:     1/2 capful/l
• Dry Miracle-Gro 24-8-16:     2.6 ml/l
• Fish Fertilizer 5-1-1:     7.8 ml/l

Measurements:

yellow cap on liquid Miracle-Gro is 5ml, so 1/2 capful is 2.5 ml per liter

dry Miracle-Gro is 0.7 g/ml, so 2.6ml is 1.82 g per liter

Micro Algae Grow is 1.085 g/ml

liquid Miracle-Gro is 1.19 g/ml

Evaporating 10 ml of liquid Miracle-Gro resulted in 3.63 g of residue. 7/2/12

10ml of fish fertilizer is 11.43g

Making 100 ml stock solutions for all three fertilizers:

• Liquid Miracle-Gro 8-7-6:     250 ul per 100 ml salt water
• Dry Miracle-Gro 24-8-16:     182 mg per 100 ml salt water
• Fish Fertilizer 5-1-1:     780 ul per 100ml salt water

The dry Miracle-Gro stock solution contains 1.82 g dry weight per liter. Based on a NPK rating of 24-8-16, 24% of that is N, or 437 mg/liter. To achieve the 12.35 mg/liter N in f/2 or L1 medium, we would need to take 28 ml of the dry Miracle-Gro stock solution, and add salt water to a total volume of 1 liter. Or 5.6 ml in 200ml of salt water

The liquid Miracle-Gro stock solution contains 2.5 ml or 2.975 g of liquid Miracle Gro per liter. Based on a NPK rating of 8-7-6, 8% of that is N, or 238 mg/liter. To achieve the 12.35 mg/liter N in f/2 or L1 medium, we would need to take 52 ml of the liquid Miracle-Gro stock solution, and add salt water to a total volume of 1 liter. Or 10.4 ml in 200ml of salt water

The fish fertilizer stock solution contains 7.8 ml or 8.91 g of fish fertilizer per liter. Based on a NPK rating of 5-1-1, 5% of that is N, or 446 mg/liter. To achieve the 12.35 mg/liter N in f/2 or L1 medium, we would need to take 28 ml of the fish fertilizer stock solution, and add salt water to a total volume of 1 liter. Or 5.6 ml in 200ml of salt water