AquaClears are great HOB
filters .. that one will be more than up to the task for a 25gal depending on what you stock with it. Stock with low bio-loads it'll work, stock with larger bio-loads like goldfish for example it's better to go with a slightly larger filter like the AC
-50 or run another a second AC
I run two AC
-70's on my 75gal ... I prefer running two filters on that tank in case one dies.
75g Planted Barbs Denison, BlackRuby, Tiger, Albino Tiger, Green Tiger, Cherry, Gold, Checkered, Odessa.
NonBarbs Cardinal, Neon, RummyNose, Bloodfin Tetras, Z. Danios. 1RTS. Amano, Bamboo, Ghost & RCS. 20g Long Shrimp Tank RCS, Tiger, Amano.