Underground filters vs. nothing

Is it better to have an underground filter where the substrate is siphoned once a week, or to just siphon the gravel once a week? I have a corner filter as well.

The water in the tank is clear but discolored, and I think the stuff trapped under the UG filter might be contributing.

It's better too have filtration especially with axies who are massive waste makers. It would make your job very difficult without a filter, and on this forum it is often said that under gravel filters are the best for axies.

if there's crud trapped under your filter, then its obviously not doing its job and you can take it out. If you're good about siphoning (i do it twice a week or more) and put in a bigger filter (a corner filter's pretty small for axies), then you probably dont need the UG filter