Aquarium Filter vs Pond Filter

I did not know there are two types of filters.  One is for pond and the other for aquarium.  The aquarium filter has a built-in pump.  So no unsightly pump in the tank.  The pond filter need a pump in the pond.  Filters are expensive.  The first one I bought was for pond by Laguna and it is more than $400.  Yesterday, I bought a aquarium pump and it is $220.  The filter has an important function of clearing up the water and processing the waste of the fishes.  I am installing the filter as my tank is outside with strong sunlight and the algae grows and turn the water into green opaque liquid.  I am in the process of make the water clear again.