coffeebean

if everything is a-ok in the tank, planted, readings are all perfect etc, is there any reason to do a water change? theoretically?

Toxic

Well, I would base it on the level of crud on the bottom and the level of algae on the glass...

haedra

I was under the impression that even if parameters are perfect, that water changes would still need to be done to replenish lost minerals and such.

But I'm no expert.

Lucy

Once your tank's cycled your water changes can be determine by your nitrates.
By changing the water your replacing oxygen and other nutrients found in fresh water. If you just top off for evaportation impurities are left behind.
Also you need to do a gravel vac to pick up excess food and waste.

FoxyGrandpa

well i do it on a certain day that i have planed. unless i am medicating my tank or somthing is wrong.other than that it is sceduled

sirdarksol

If all readings are fine, and you haven't lost a lot of water to evaporation, there isn't necessarily a reason to do a water change (though a gravel vac will help keep your nitrogen readings from jumping the next week).
It's a bad idea to just top a tank off, though, unless you use RO or distilled water to do so, because topping a tank off with tap water adds to the mineral concentration.

aquarist48

My opinion is....If you don't do routine water changes your fish will not survive. Not getting fresh water means they are swimming in their own waste. Water changes are a must and should not be neglected. Same goes for filter floss it must be changed.

Butterfly

Even though your water test readings are good, you have to consider what you may need to replace that has been used up, like oxygen and minerals. Along with the waste in the substrate that needs to be vacuumed out Total Dissolved Solids(TDS) also need to be considered. These are the organic substances that are dissolved in the water. The picture I have in my mind is that without water changes the water gets thicker and thicker (like adding potato flakes to water). I know that's an over simplification but it helps me understand
A good friend wrote this article awhile back and it explains TDS much better than I can.
http://www.aquascapingworld.com/maga...Explained.html
Hope it helps you understand better, it sure did me.
Carol