Water Changes

[Noahsfish]

Hey guys, thought I'd make a thread on this as it seems there's always been controversy over this.. It's basically common knowledge that the water of an aquarium doesn't contain much bacteria. When visiting a friends and seeing her aquariums she thinks that doing water changes every other day or daily is bad for the fish, and that it will stress them..on the other hand one of my friends who works at the lfs has a few tanks, one of them with a gbr pair that he does daily 30% changes to keep the water pristine. What are your guys thoughts on this, I think it depends on the situation. Like, for example I know some peoples ph changes after being put into the tank if they don't let it sit, and doing drastic water changes could prove fatal for some fish, and also temperature matching could be a problem. I normally do 20% water changes every wednesday or Thursday and another one on either Saturday or Sunday.

 

[Shaddex]

On my cory tanks (220 and 110ltr) I do a 50% water change weekley.
On my Daughters Rio 180 I do a 50% every 2 weeks or so
 
Simples...
 
Regarding "too much water changing" I would imagine that repeated water changes could shock the fish, but that would depend on if you are just throwing the water back in to the tank.  I prefer the syphon the water back in at a nice easy rate.

 

[CJH0825]

I was told the same thing, that doing water changes causes stress to the fish. I do 25 - 50% water changes atleast twice a week just to keep everything in line and keep my water pristine.

 

[eaglesaquarium]

There's no such thing as too many water changes.  The place these fish come from has a continual turnover of water from upstream.  
 
 
Doing too little water changes, lead to something called "old tank syndrome".  Doing too many water changes leads to ... healthy fish in clean water.

 

[levahe]

I think some species of shrimp are sensitive to large water changes, but on the whole large water changes can only do good. The fish will be stressed out more by dirty conditions if regular maintainance isn't carried out. I'm not convinced that PH changes would be big or severe enough to harm any fish though.
I always use water conditioner and make sure the water is close to the tank temperature, and I do minimum of 50% a week on my large tank (co2 + E.I. ) and 25% on my low tec planted shrimp tank.

 

[snazy]

 Like, for example I know some peoples ph changes after being put into the tank if they don't let it sit, and doing drastic water changes could prove fatal for some fish, and also temperature matching could be a problem.
 

 
The ph difference is normally due to some extra CO2 or other gasses in the tap water, so it doesn't really stress the fish as the hardness of the water is the same despite the difference in Ph.
Matching the temperature is quite easy by mixing it with hot water from the tap and it doesn't need to be exact.
Large water changes will only be a problem in a tank that has been neglected for a very long time because the tap and tank water parameters will become drastically different. In a tank with no water changes the Kh normally goes down, so that causes the Ph to drop eventually.  The Gh normally goes up if one tops up with tap water instead of Reverse osmosis due to the constant build up of calcium and magnesium and other similar minerals which can not evaporate. The TDS(total dissolved solids) also goes up in a tank with no water changes.
If one does regular large water changes, which is better for the fish, then no need to worry about stressing fish. 50% at the time max is fine for the most sensitive of species in most circumstance.  I do that on a shrimp tank as well.

 

[Noahsfish]

Yeah, I guess what I'm saying is that on the whole the more water changes the better, but in some circumstances, like a lightly stocked or very well planted tank more water changes aren't necessary. I always change at least 40% of my water a week though even on my shrimp tank.

 

[eaglesaquarium]

I agree with this ^^^.
 
However, there's a difference between "not necessary" and harmful.    Water changes are EXTREMELY rarely harmful.  And even in a lightly stocked tank, more water changes generally is better than less water changes.