It depends on what you are attempting to use it for.
Seachem Nourish is promoted as an iodine supplement, to remove any potential for thyroid issues.
Amounts per 1 g
Crude Protein (minimum) 1.7%
Crude Fat (minimum) 0.2%
Crude Fiber (maximum) 0.2%
Moisture (maximum) 94.2%
Ash (maximum) 2.0%
Iodide(minimum) 0.008 mg/g
Ingredients: water, spirulina (Spirulina platensis), chlorella (Chlorella pyrenoidosa), phosphoric acid, calcium chloride, magnesium chloride, ferrous sulfate heptahydrate, zinc sulfate heptahydrate, copper sulfate pentahydrate, potassium iodide, manganese sulfate.
Complementary feed for ornamental fishComposition: Water, Algae, Fats and oils, Minerals. Nutritional Additives per liter: Vit. C 520 mg, E1 iron 30mg, E6 zinc 15mg, E2 iodide 9mg, E4 copper 3mg, E5 manganese 2mg, E8 selenium 368ug. With antioxidants
Boyd Vitachem is promoted as a multi-vitamin/amino acid supplement, for overall increased vitality and health.
Guaranteed analysis (All per ounce): Crude protein (min) 21.8%, crude fat (min) 0.09%, crude fiber (max) 2%, moisture (max) 90.1%.
Ingredients: Vitamin A-5000 IU, vitamin B12-40 mg, vitamin E-32 mg, thiamine hydrochloride 25 mg, vitamin K-20 mg, vitamin C-18 mg, vitamin B1-15 mg, vitamin B2-15 mg, vitamin B6-12 mg, biotin 4 mg, L-leucine 4 mg, lysine monohydrochloride 3 mg, D-l phenylalanine 3 mg, L-arginine hydrochloride 2.5 mg, D-l isoleucine 2 mg, threonine 2 mg, l-methionine 1 mg, L-histidine hydrochl .
Note that Boyd Vitachem contains B1 (15 mg per ounce), which when feeding frozen food can become very important, as B1 supplementation can neutralize the negative health issues resulting from exposure to thiaminase enzymes.