Artful Intelligence.

Compared to conventional fertilisers (largely developed pre-2000s for 'fish tanks' with simpler / hardy plants):
3X more concentrated for demanding species*
2X more potassium for richer colours^

Dose 3ml per 100L daily.
 

#200ml

200ml lasts ~3mths for an 18 Gal / 70L tank. Pump not included.

#500ml

500ml lasts ~3mths for a 50 Gal / 190L tank. Pump not included.

#1000ml

1000ml lasts ~3mths for a 100 Gal / 380L tank. Pump not included. 

#standard

Our Standard 300ml Pack comes with a calibrated pump. 1ml per press.
Lasts ~3mths for a 30 Gal / 115L tank.

#starter

Our Starter 100ml Pack comes with a calibrated dosing dropper.
Lasts ~3mths for an 8 Gal / 30L tank.

#600ml

Comes with a calibrated pump. 1ml per press.
Lasts ~3mths for a 60 Gal / 230L tank.

Why

*in terms of total soluble elemental fertiliser per ml.
^in terms of the amount of potassium per ml.

APT 1 replicates APT 3's winning formula without nitrates and phosphates. This gives maximum algae control for new tanks (we recommend all tanks to start with APT 1 for the first 1-3 months), and optimal long term performance for tanks with more fish. This is because fish food and waste already supply phosphates and nitrates.
FAQ Here.

Ingredients

GUARANTEED ANALYSIS
Soluble Potash (K2O)....................................... 5.5%
Magnesium (Mg)............................................. 0.85%
Iron (Fe) ...........................................................0.1%
0.1% Chelated Iron

Derived from: Potassium Sulphate, Potassium Chloride, Magnesium Sulphate, DTPA Iron, EDTAIron, EDDHA Iron

Further information here.