What makes your water dirty is overfeeding and overstocking. Also a biologically unstable tank will be cloudy. To achieve a "crispy" tank, regular and somewhat large water changes will improve clarity. Make sure you get under rocks and driftwood, that's where the mulm is. Also, stock wisely. An overstocked tank will have clarity problems especially if it is not appropriately filtered.
Having plants in the water will combat the algae and take in the light and nutrients (basically crap) and filter the water. Great "filter" plants include types of moss and other bushy plants.
In most cases, overkill with filtration is non-existing. Unless you are keeping frail and weak swimmers, get as much filtration as you can. Also, having two filters is much better than one powerful one. This is because if you need to clean the filter you still have a backup.
Also, diatom filters do wonders but are very expensive.
Do NOT waste your money on water clarifying chemicals, they can be iffy.
Good luck!