goldfish_lover's question about Water Changes

so for normal tanks how often and how much should you change the water in a tank?

 

i dont think i posted this...???
but its a good question maybe???

 

I split this off into its own thread so we could keep the other one on track.

The simple answer is any time your ammonia/nitrIte is above 0 or your nitrAte is above 20.

The more complex/in depth answer:

Fish produce ammonia. Ammonia is toxic to them (it basically causes chemical burns on their bodies, fins, and gills). In an estiblished filter, there is a type of bacteria that eats up the ammonia, but as a result, the bacteria also produces nitrIte which is also toxic to fish (binds with the red blood cells making it difficult for the fish to utilize oxygen - basiclaly it suffocates them). So there's a 2nd type of bacteria in the filter that eats up the nitrIte and produces nitrAtes. NitrAtes aren't too bad as long as they stay below 20ppm. The problem is, there's no bacteria to eat up the nitrAtes (there is, but it lives in oxygen-free environments which normally don't exist in aquariums).

So, as the fish produce ammonia, the bacteria in the filter converts it to nitrIte then nitrAte. Normally, in a properly stocked and properly filtered established tank, the bacteria should be able to keep up with the fish so that there is never any amount of ammonia or nitrIte present (it gets eaten/converted as it is produced). So that just leaves the nitrAtes which build up over time (again, because there's no bacteria to eat/convert it). So the most practical way to remove nitrAtes is to do water changes (large enough & frequent enough to keep the level below 20ppm).

Ideally, you should stock the tank so that 20% - 30% water changes once a week are enough to keep the nitrAtes below 20 (more on this later).

Occasionally, if something bad happens to your filter (like you replace your media or use a certain chemicals), you will lose some of your beneficial bacteria. When that happens, you don't have enough bacteria to keep up with the amount of ammonia being produced by the fish. In that case, you'll start getting readings for ammonia & nitrIte. If that happens, you need to do fairly frequent water changes to get those levels back down to 0 as quickly as possible (remember, they're toxic).

Also, when you first start up a tank with new filters and throw in fish, you won't have any bacteria so the ammonia & nitrIte levels will get high until the bacteri starts growing. So in that case you'll also have to do a lot of frequent water changes to keep the fish from getting poisoned.

Or if you don't have enough filtration for your tank, if there's too many fish, or the tank is too small, there either won't be enough room for the bacteria to live (inadequate filtration) or not enough water to dillute the ammonia produced by the fish (too many fish/too small of a tank) and you'll also see ammonia & nitrIte readings.

So, back to the simple answer: Any time your readings for ammonia or nitrIte are above 0, do water changes (shouldn't happen very often under normal circumstances). For the nitrAtes, you'll want to test your water fairly frequently and do water changes once the nitrAtes get around 20. Eventually you'll figure out a schedule that works for you (remember, though, that as your fish get bigger, you'll be getting nitrAtes more quickly so your water changes will have to get bigger/more frequent). And, like I said before, ideally you should try to stock the tank so that weekly 20% - 30% water changes are enough to keep nitrAtes below 20.

Can you do bigger/more frequent water changes if you keep a heavily stocked tank? Yes. Do I advise it? No, because it tends to lead to burn out (constantly having to clean a fish tank isn't fun and most people eventually get tired of it and start neglecting the fish) and it also leaves very little room for error (if you're having to do water changes 2 - 3 times a week, what happens if you go on vacation for 2 weeks?).

Hope that doesn't confuse you too much.

-Chelle

 

You posted it in a different thread but I split it off into its own thread.

-Chelle

 

ohh ok thanks...and so yeah i guess i have to buy that to test the levels... :?