If you have live aquarium plants in your tank, you are probably familiar with Seachem Flourish Excel (or just Excel). It’s a liquid-based carbon source that helps boost plant growth and can help reduce algae. I swear by the stuff, but it can be seriously expensive.
It turns out it’s the same chemical as found in the industrial sterilizer Metricide. Hat tip to the good folks on Reddit for pointing it out in this thread.
Industrial cleaning chemicals are way cheaper than aquarium ones apparently. You can get a gallon jug for 20 dollars including free shipping on Ebay. Talk about cheap Seachem Excel!
Important tip: the Metricide comes with an activator solution. DO NOT USE IT. That activates the chemicals for sterilizing and would be very bad for your fish tank.