Reasons for water changes

[Lcc86]

I do mine similarly to you @AJ356, mainly out of routine. Only difference is mine are heavily planted so I reckon I probably don't need to do a weekly change. I inadvertently miscalculated the size of my frog tank so it is slightly overstocked so I prefer to keep on top of that one, and because my other tank is next to it I just do that one as well while I'm there! I also still class myself as a novice even though it's been a few years now, so may not be as experienced as others who go down the walstad route, for example. So there's probably an element of fear of not wanting to mess up or leave too much waste in the tank etc.

 

[gwand]

My brush my teeth twice a day. I change the water in my tanks weekly. Just another routine.

 

[TwoTankAmin]

Actually, a planted tank can need water changes as much as the fish. This is especially true if one adds fertilizers for their plants. Not everything in a fertilizer may be needed by plants. They may need some things in lesser quantities than is supplied by what we add. So, of the plants do not use them, they will build up if we do not do regular water changes.

I have planted tanks where I have no fish for a while. I dose ammonia in them to feed the bacteria and because the plants will use it also. I still add ferts, but usually the not nitrogen ones. And I also do water changes on them.

Tanks are closed systems and they will end up with too little and too much of things if we do no water changes. Think of a 50% weekly water change as resetting the balance of almost everything in the tank back to normal levels.

Unless one is a real plant nerd and runs a more high tech type of tank, it is a lot less work to dose ferts weekly after a the water change than to work on the tank more frequently and to dose the individual ferts instead of a more comprehensive fertilizer less often.

But weekly water changes are the easiest way to insure things are neither lacking nor building up. Unless one's tap water is causing issues in this respect, I would go with the weekly change planted or not.

I ran a high tech planted wank with pressurized CO2 and regular fertilizing for almost a decade. I gave it up because that tank required way to much of my time than my other tanks. But then I had 20 total and 13 planted but only that one with CO2 etc. I plant heaily for the most part but use low to medium light plants which makes my life a lot easier.

Of course each of us must decide how we want to do any given tank, What matters is that any tank remains healthy and not overly demanding as we increase the number of tanks we have.

I believe that the more heavily planted any tank is, the more it needs weekly changes.

 

[GaryE]

I myself am doing lesser water changes than an average aquarist. But that's because my tanks are well balanced. And in such a case less water changes are needed.
But in general. there's no specific amount of water changes per moment or even the frequency of it as a rule. For it depends on multiple factors. There are fish that thrive better when the tank is a bit polluted, there are fish that prefer less till none pollution in a tank. Same goes for plants. is there a sick fish? Or is the tank troo polluted. Or is there a lack of oxygen in there? Do you want fry to grow up faster? And so on...

I've got a number of fish that don't thrive well when too many water changes is in play. These thrive well in dirted water and even reproduce better in there.

k
THis brings up an element I always seem to harp on - what fish are involved? Like @emeraldking , I know livebearers well (though not as well as he does). I had about 5 years when they were the main fish in my set up, and I've always kept a few around. They are very tolerant of lower rates of water changing. They were the one group I could count on to survive when I believed balanced aquariums were possible, in my teens. Then, like almost all the hobby, I changed no water and still bred buckets of variatus platys and guppies.

If I tried the same regime with the fish I have now, their lifespans would be chopped from 5-10 years to 5-10 months. Even within the same groups - some of my killies do fine with fewer water changes, but others would be doomed quickly. Don't ask me how I know. I have learned none of my fish do poorly when the water's changed, if it's several times a month. Changing from very dirty water (after a month) to very clean can kill the fish. It's too large a change in many cases. But every week to ten days and things go swimmingly for the fish I choose to keep. Peaks and valleys are for vacations, not water quality.

I also have soft water - a treat. But it has a downside, as poorly buffered water needs regular changing or it crashes.

So we have the regular discussion of the benefits of water changes, but we also have the question of frequency and percentage, which can be influenced by the natural history of the fish we keep.