Liquid Fertilisers for Planted Aquariums

Choose by the balance of plants to fish in your tank. APT 3 suits tanks with more plants than fish, and is the standard choice for a planted aquarium. APT 1 carries the same formula with zero nitrate and phosphate, for tanks with a heavier fish load - where food and waste already supply both - and for new tanks in their first one to three months, when algae pressure is highest.

APT e is a ready-made, calibrated version of the Estimative Index approach, for heavily planted Dutch-style tanks and hobbyists who dose to EI logic.

APT Dew is a foliar spray rather than a water-column dose: it is for mosses, ferns and emersed foliage in terrariums and paludariums.

No. Plants absorb nutrients in fixed proportions, and anything supplied beyond that ratio does not accelerate growth. It stays in the water column, where algae can use it. Nitrogen works in the opposite direction to intuition: lower nitrogen deepens red pigmentation, up to a point. APT's Capstone ratio is calibrated to sit at that point - maximum colour before diminishing returns.

Roughly 3ml per 100L daily, at any consistent time of day. Consistency matters far more than precision; when in doubt, dose slightly less rather than more. Use the dosage calculator for tanks without CO2, or those dominated by slow-growers and shade plants. Minor sedimentation in the bottle is normal.

Changing fertiliser can briefly shock a system, and in rare cases trigger algae. Introduce APT incrementally over two weeks rather than switching overnight. Do this by using a half-dose of your existing fertiliser + a half-dose of APT, for 2 weeks. After that, switch to APT completely.