Seachem Flourish 500 ml and Seachem Flourish Excel 500 ml Bundle Review (2026)

Who this bundle is for

This bundle pairs a bottle of Seachem Flourish, the base trace and micro element supplement, with Flourish Excel, a bioavailable organic carbon source. It is aimed at planted tank owners who are not running pressurized CO2 and want to give their plants an alternative carbon supply alongside general nutrients. It suits low to moderate light tanks with easy to moderate plant species, and it can also serve as a supplemental carbon boost in a CO2-injected tank that wants extra insurance during high-growth periods. It is a poor match for tanks stocked with vallisneria, anacharis or other carbon-sensitive species, since those plants can react badly to Excel.

What each bottle actually does

Flourish supplies calcium, magnesium, iron and a broad base of micro and trace elements at a dose of one capful, 5 mL, per 250 liters or about 60 gallons, once or twice weekly. Flourish Excel delivers simple organic carbon compounds, described by the manufacturer as photosynthetic intermediates, that plants can use as an alternative or complement to CO2 gas. Initial dosing after setup or a large water change is one capful, 5 mL, per 40 liters or 10 gallons, dropping to one capful per 200 liters or 50 gallons daily or every other day for maintenance. Flourish Excel also has iron-reducing properties that convert iron into the ferrous form plants absorb more easily, so it does double duty as both a carbon source and a mild iron booster.

Living with the dosing routine

Running this bundle day to day means two separate bottles with two separate schedules, Flourish on a weekly cadence and Excel on a near-daily one, which takes more manual attention than a single all-in-one bottle. Because Excel's dose ramps down after the initial dosing period, it is worth marking a calendar or setup date so the daily dose does not linger longer than needed. Owners commonly keep Excel on a strict daily habit since missed doses reduce its algae-limiting benefit, while Flourish is easier to fold into a weekly water change routine. Neither product replaces the need to test water parameters occasionally to confirm the nutrient load is not building up between water changes.

Honest trade-offs and how it compares

The clearest caution with this bundle is that Flourish Excel can melt sensitive stem and rosette plants, vallisneria being a commonly cited example, if the dose runs high, so new users should start conservatively and watch plant response before increasing it. Liquid carbon from Excel is also generally considered less effective at driving fast growth than pressurized CO2 injection, so tanks aiming for a dense, fast-growing carpet may eventually outgrow what Excel alone can support. Compared with the Flourish and Flourish Potassium bundle, this Excel version is the better choice when the goal is carbon supplementation or mild algae suppression rather than correcting a specific potassium shortfall.

Verdict and who should look elsewhere

Pick this bundle if your tank runs without CO2 injection and you want a coordinated way to add both general nutrients and a carbon source in one order, which lines up with our score of 8.6 out of 10 for a well-matched, complementary pair. Look elsewhere if your tank already injects pressurized CO2 and does not need a supplemental carbon source, if you keep carbon-sensitive plants like vallisneria, or if your main issue is a specific macro nutrient gap like potassium or nitrogen, where a more targeted Flourish pairing fits better.

Frequently asked questions