Review on 🧼 EHEIM Substrat Pro Bio Filter Media (Sintered Glass Pearls) 5L by Erica Rogers

I use this in my Ecco Pro 300 in a 25 gallon guppy tank with built in UV light. I've had the same strain of guppy in this tank for over 8 years with no problems. No sick fish. The water is always crystal clear. I also do 20% water changes every week. I also use pothos plants to keep the water clear. No carbon, no ammo, no chemicals, nothing but water. I have been using Eheim filters and other products since 1982.