It is essential to maintain the quality of water in the filtrations system. As per the guidelines, you must have to change the water as recommended by the experts. You must have to change 10 percent of the water per week as recommended by the experts. If you install larger tank than you must have to replace 25 percent water.
You must have to check the pollution of the water based on the number of fishes in the tank and types of water tank. I think you must have to manage the aquarium based on the present condition.
There are different sizes of the aquarium available in the market. Based on the population and types of fishes, you need to get change the water. You must have to get your aquarium clean.