water changes

[oranium]

hi guys... you all know that water evaporates in the tank right... ok lets say after a few days the water level in the tank drops... i top it back up with fresh water... by doing this over a long period of time... do i still need to do water changes like 20% or more... or toping up with water everday is good enough ?...

[Morgan]

Topping water only replace evaporate water.

Waste products from fishes does not get evaporate with the water.

Water changes is still required to dilute all these waste accumulation.

[oranium]

okie !!

so how many times a month should i do a 20% water change if my tank size is 4x2x2 ft ?

[ong]

Once a mth. 10% is enough.