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Liquid carbon
fertilizer
Used for: Planted tanks, CO2 injection, Tank maintenance
Specifications
| Specification | Value |
|---|---|
| Volume | 500 ml |
| Dose | On initial use or after a major (> 40%) water change, use 1 capful of Flourish Excel (5 mL) for every 40 L (10 US gallons). Thereafter, use 1 capful for every 200 L (50 US gallons) daily or every other day. |
Source checked on 2026-10-02.
| Specification | Value |
|---|---|
| Volume | 8 fl oz (237 mL) |
| Dose | 1 ml for 10 U.S. gallons or 5 ml for 50 U.S. gallons, once a day |
Source checked on 2026-10-02.
Description
Liquid carbon products are supplements offered for aquarium plant growth. They provide an alternative form of carbon input rather than a cylinder, regulator and diffuser system. Check the actual formulation and whether the product is intended for your aquarium and plants. Seachem Flourish Excel and API CO2 Booster are distinct examples, each with its own directions. Both manufacturers describe use alongside an injected CO2 system. A liquid product should not be treated as a measured increase in dissolved CO2 gas or as a dose-equivalent replacement for gas injection. Follow the exact label and account for plant sensitivity. Seachem identifies Anacharis as sensitive to Excel and advises a less frequent schedule for that plant. It also warns that overdosing or applying Excel directly as an algae spot treatment can damage plants. Do not transfer this product’s formulation or dosing schedule to another liquid carbon brand. The listed capacities and doses belong to the named products. Recheck the instructions when changing bottles or formulations, and observe the aquarium’s response. A liquid carbon supplement does not supply all the other nutrients plants require.
Sources
- seachem.com — https://www.seachem.com/flourish-excel.php
- apifishcare.com — https://www.apifishcare.com/products/api-co2-booster-freshwater-aquarium-plant-treatment
Further reading on identification and aquarium care.
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