The truth must come out

[nerdyguy83]

The one thing that no one seems to ever mention in these debates is the WHY of doing water changes, at least not in depth. Nitrates are the most cited reason, but nitrates themselves aren't going to kill your fish. Nitrates are an indicator of other disolved organic compounds that could kill your fish if levels get high enough. If you have a planted tank, then some of this is taken care of (I'm no expert with planted tanks, so this is all talking about unplanted). So the bottom line would have to be that for a healthy tank, weekly water changes of anywhere between 20-50% should be done. If your tank has a high bioload, then do more towards the 50%. Even if the tank doesn't "need" it, it is better to have a good habit rather than a bad one.

I personally don't understand people who constantly ask this question because it seems to imply that people get into this hobby, get bored with it, and then want to do the bare minimum to get by. If you like your tank for the look it gives to a room and not because you're way into the hobby, you should still take care of it. If you really are that bored with the hobby, give your fish away, sell your equipment, and spend the money on something else. You wouldn't go weeks without vacuuming your living room, so don't go weeks without doing the same to your tank. I'm not trying to rant or be harsh or anything, I'm just always surprised how often the question of "how little can I do?" comes up in a community of people that is supposed to be comprised of fish lovers.

 

[bigscout]

So the bottom line would have to be that for a healthy tank, weekly water changes of anywhere between 20-50% should be done. If your tank has a high bioload, then do more towards the 50%. Even if the tank doesn't "need" it, it is better to have a good habit rather than a bad one.

And use your Nitrate test to tell you if you are keeping things steady or not. If the numbers climb in spite of your efforts, increase the volume and or frequency. If they do not climb over time, then you are doing enough work to maintain things. Its really pretty simple.

i have a 40 gallon tank filttered and filled with fish and some plants and never change my water and i never have problems and the quality is alsways right. adding fish is simple enough just let the fish sit in the bags in the aquaium water for 30min and before releaseing put food in the tank to prevent other fish from being in the way.

Would you care to make a wager on that? What is your TDS level, What is your Kh, GH, and pH. How long has the tank been running and when was the last time you added a new fish. Here is an article on OTS that may help you out.
OTS by RTR

 

[Roan Art]

...Would you care to make a wager on that? What is your TDS level, What is your Kh, GH, and pH. How long has the tank been running and when was the last time you added a new fish. Here is an article on OTS that may help you out.
OTS by RTR

Further to that, here are some more of RTR's articles on water chemistry:

Waterchanges: Why, How Much and How Often
http://aquafacts.net/wiki/index.php/Waterchanges:_Why,_How_Much_and_How_Often

Water Change Math
http://aquafacts.net/wiki/index.php/Water_Change_Math

If you are not aware of who RTR is, there is a brief bio at the bottom of each article page.

Roan

 

[CBTF]

I think water changes are an individual this for all tanks. Some fish are really messy- some arent. Some tanks are overstocked, others arent. Not to mention how much the owner feeds them..

It's more a trial and error thing, but I do mine every two weeks.

 

[Ms.Bubbles]

Tank size and type does affect the need for water changes to some degree. For example, a betta in a 1 or 2 gallon non-filtered tank requires larger or else more frequent water changes than a betta in a filtered 10 gallon, because there is less fresh water and good bacteria to dilute/process the fish's ammonia output--therefore the small tank will get nasty faster.

It is not always true to say that people who wish to do fewer/smaller water changes are bored with their fish and want to do as little as possible to maintain them. In this current environmental climate of global water shortages (which is apparantly going to get worse as global warming increases), some people simply don't wish to waste water unnecessarily.

I try for a moderate water change schedule--25% of my filtered tank's volume once a week, more for my unfiltered planted tank. Even that is probably too much (I have plants in my tank who depend on the nitrates), but I think it's a nice middle of the road approach.

Weekly water changes are better than every 2 weeks or monthly because they keep the water in the tank close to the parameters of the source water--which will be less shocking for the fish if a strange or unexpected event occurs in the tank and a large water change is necessary.

 

[wesleydnunder]

Weekly water changes are better than every 2 weeks or monthly because they keep the water in the tank close to the parameters of the source water--which will be less shocking for the fish if a strange or unexpected event occurs in the tank and a large water change is necessary.

I'm glad you made that point Ms. Bubbles. I think Bob touched on it as well. Newbie101balla, as you read in RTR's article and from others in this thread, the closer you keep the tank water to source water, the better off your tank health will be. Raskolnikov put it best: "Water, water and more water".

Mark