Tropica fertiliser dosing calculator
Tropica's two liquids are dosed once a week at the water change. Here is the label dose for common tank sizes, in mL and pumps, and what it adds.
Which one?
- Specialised Nutrition contains nitrogen and phosphorus plus micros, for fast-growing or demanding plants. Declaration (w/w): N 1.3 %, P 0.1 %, K 1.0 %, Mg 0.4 %, Fe 0.07 %, Cu 0.006 %.
- Premium Nutrition has no nitrogen or phosphorus: K 0.8 %, Mg 0.4 %, Fe 0.07 %, Cu 0.006 %. It suits tanks with fish load or substrate supplying N and P.
Both: 6 mL (3 pumps of 2 mL) per 50 L each week. Tropica says to set the dose to plant needs and, if algae starts with Specialised, cut the dose by 50 % and change water 50 % more often.
Weekly dose by tank size
| Tank | Specialised Nutrition | Premium Nutrition |
|---|---|---|
| 10 gal (38 L) | 4.5 mL | 4.5 mL |
| 20 gal (76 L) | 9.1 mL | 9.1 mL |
| 29 gal (110 L) | 13 mL | 13 mL |
| 40 gal (151 L) | 18 mL | 18 mL |
| 55 gal (208 L) | 25 mL | 25 mL |
| 75 gal (284 L) | 34 mL | 34 mL |
| 125 gal (473 L) | 57 mL | 57 mL |
Pumps = mL ÷ 2. For 151 L (40 US gal) that is about 9.1 pumps a week.
What a weekly dose adds
At 6 mL per 50 L (1.0 g/mL assumed), Specialised adds about 6.906 ppm NO3, 0.368 ppm PO4, 1.2 ppm K, 0.48 ppm Mg, 0.084 ppm Fe, 0.007 ppm Cu per week. That is far leaner than EI's 22.5 ppm nitrate a week. Part of the nitrogen is ammonium, so the nitrate-equivalent figure is an upper bound for what a nitrate test sees.
FAQ
How many pumps of Tropica Specialised Nutrition per week?
Tropica recommends 3 pumps (6 mL) per 50 L once a week. That is roughly 4.5 pumps for 20, 9.1 pumps for 40, 17 pumps for 75 US gallons.
Is Tropica fertiliser safe for shrimp?
Both products contain a little copper (0.006 % w/w). At the label dose this adds about 0.007 ppm copper per week; many shrimp keepers dose lower. Check your tap water copper too.
Specialised or Premium Nutrition?
Use Specialised if plants show nitrogen or phosphorus shortage (pale old leaves, stunted growth) and you have few fish. Use Premium if nitrate is already present from fish waste or a rich substrate.