Seachem Flourish Excel (500 ml) is a source of bioavailable organic carbon. Plants require a source of carbon which is usually obtained from CO2, but, may also be acquired from simple organic compounds (such as photosynthetic intermediates).
Flourish Excel can be used alone or in conjunction with CO2 injection. Further benefits include iron reducing properties which promote the ferrous state of iron (Fe+2), which is more easily utilized by plants than ferric iron (Fe+3).
DIRECTIONS:
On initial use or after a major (> 40%) water change, use 1 capful (5 mL) for every 40 L (10 gallons*). Thereafter use 1 capful for every 200 L (50 gallons*) daily or every other day. Dosing may be slowly increased in high-growth aquariums. For smaller dosing please note that each cap thread is approximately 1 mL.
Good plant growth booster if you run a low-tech system and don't dose CO2 - non-advertised beneficial side effect is that active ingredient is also an algaecide.