Water change

[Eric Nelson]

I currently have two 28 gallon tanks.

I set one up without a cover.

I lose about two liters a week to evaporation in the uncovered tank.
My question is if I’m adding two liters of water a week do I still need to do a frequent water change?

The tank is stocked with nine cardinal tetras, six Cory cats, one nerite snail, dwarf hair grass, Java fern and water sprite.

I check my parameters weekly and they stay within acceptable limits.

Than you

 

 

 

[Brian]

Yes, frequent.  As to what is frequent I will let you decide.   But topping off an aquarium is only doing that.   Look at it like this, aquatic animals live in their own waste.   We need to, with filtration, plants and water changes try to keep it all in balance.   
Good Luck 

[Colu]

I would do 25% weekly water changes  but all depends on your stocking levels if it's heavily stocked and you don't have live plants then I would do a 50% weekly water changes

[lefty o]

frequency depends on you and the water conditions. one thing to think about, when water evaporates out of the tank, it leaves the bad stuff behind , so just adding water does not combat that.

[YIACrazy]

Topping off is not at all the same as a water b change. If you have 29 gallons of nitrates and 4 gallons evaporates, you have 29 gallons of nitrates in 25 gallons of water. When you top off, it goes back to being 29 gallons in 29 gallons. As for frequency....as with everything else, they are right. If your plants help balance your tank, then you decide the frequency. Sounds like you have a good plant to stock ratio...