Best Fertilizers for Planted Aquariums
Plants in a closed aquarium cannot draw nutrients from an infinite soil reservoir the way terrestrial plants do. Carbon, nitrogen, phosphorus, potassium, and a suite of micronutrients all need to be replenished as plants consume them and water changes dilute them. All-in-one liquid fertilizers like Seachem Flourish Comprehensive and APT Complete simplify the routine by combining micros and some macros in one dose. Dedicated macro and micro dosing suits EI or estimative index practitioners who want fine control. Carbon supplementation with glutaraldehyde-based products like Seachem Flourish Excel can supplement or partially replace CO2 injection in low-tech tanks.
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The short answer
APT Complete from the 2Hr Aquarist is the top pick for planted tank fertilization, covering macros and micros in a single daily or every-other-day dose formulated specifically for planted aquariums by one of the hobby's most respected methodology researchers. For hobbyists who prefer a widely available retail option with proven track record, Seachem Flourish Comprehensive is the reliable all-in-one that suits most planted tanks at any fish store or on Amazon.
APT Complete All-in-One Planted Tank Fertilizer
$22-$35 mid
All-in-one liquid fertilizer formulated by the 2Hr Aquarist covering macros and micros in a single dose, designed for low-dose daily use in planted aquariums with or without CO2.
- Covers macros and micros in one bottle, eliminating multi-part dosing
- Formulated by a respected planted tank methodology researcher for real planted tank needs
- Suitable for tanks with or without CO2 injection
Slightly more expensive per dose than Seachem Flourish Comprehensive
Verdict The top all-in-one fertilizer for planted tanks: science-backed, simple, and effective.
Seachem Flourish Comprehensive Supplement
$10-$20 budget
The most widely available liquid plant micronutrient supplement in the hobby, covering trace elements, amino acids, and botanical compounds used by aquatic plants weekly.
- Widely available at any pet store and on Amazon; easy to restock
- Broad trace element coverage in a single supplement
- Trusted brand with decades of hobby use behind it
Does not include significant nitrogen or phosphorus; macros must be supplemented separately in nutrient-hungry tanks
Verdict The most available planted tank fertilizer; a solid entry-level micronutrient supplement.
NilocG Thrive All-in-One Liquid Fertilizer
$15-$28 mid
Community-formulated all-in-one planted tank fertilizer covering macros and micros in a concentrated formula, popular in planted tank forums for its value and effective coverage.
- Covers macros and micros in one bottle at a competitive price per dose
- Strong community following in planted tank forums and subreddits
- Concentrated formula; a small bottle goes a long way
Less widely available than Seachem in retail stores; primarily online purchase
Verdict A value-priced all-in-one alternative to APT Complete with strong forum backing.
Seachem Flourish Excel Liquid Carbon
$12-$25 budget
Glutaraldehyde-based liquid carbon source that provides bioavailable carbon as a partial CO2 substitute for low-tech planted tanks and an algae suppressant for high-tech tanks.
- Provides bioavailable carbon for low-tech tanks without pressurized CO2
- Doubles as an effective spot-treatment for BBA and hair algae at higher concentrations
- Pairs well with Seachem Flourish Comprehensive for a simple two-product routine
Not a full CO2 replacement; growth results significantly trail a proper pressurized CO2 system
Verdict The standard liquid carbon for low-tech tanks and an effective algae spot-treatment.
The method
How we chose
We evaluated each option on fit, build quality, daily usability, and value. Our top pick, APT Complete All-in-One Planted Tank Fertilizer, earned the spot because the top all-in-one fertilizer for planted tanks: science-backed, simple, and effective. The comparison above highlights exactly who each pick is best for.
Head-to-head comparisons
FAQ
Best Fertilizers for Planted Aquariums: FAQ
What is the difference between Seachem Flourish and Seachem Flourish Excel?+
Seachem Flourish Comprehensive is a broad-spectrum plant micronutrient supplement covering trace elements, amino acids, and some vitamins. It does not contain significant nitrogen, phosphorus, or potassium. Seachem Flourish Excel is a carbon source based on glutaraldehyde that provides bioavailable carbon as a partial substitute for CO2 injection. They serve different purposes and are often used together in low-tech setups.
Is Seachem Flourish Excel safe for shrimp?+
Excel contains glutaraldehyde, which is an algaecide and biocide at high concentrations. Overdosing it is harmful to shrimp, snails, and mosses. At the recommended dose for a normal planted tank it is generally considered safe for neocaridina shrimp by many hobbyists, but caridina shrimp and crystal shrimp are more sensitive. If you are keeping expensive caridina, avoid Excel or use extremely conservative doses and monitor closely.
How often should I dose fertilizers in a planted aquarium?+
Frequency depends on the system. In a high-tech tank with CO2 and fast-growing plants, daily or every-other-day dosing replenishes nutrients as plants consume them rapidly. In a low-tech tank with slow growers, dosing once or twice a week after water changes is common. Some all-in-one fertilizers like APT Complete are formulated for daily micro-dosing, while traditional EI dosing uses larger weekly doses with a water change reset.
Are root tabs necessary if I am using an active substrate?+
Active soils like ADA Amazonia and Fluval Stratum release nutrients from the soil, so root tabs are often unnecessary for the first six to eighteen months. As the soil depletes, heavy root feeders like Amazon swords, tiger lotus, and cryptocorynes benefit from root tabs placed near their roots. In inert substrates like pool filter sand or plain gravel, root tabs are important for root-feeding plants from the start.