Water Changes, How Much Is Too Much?

[kakihara]

Hi,

I almost trebled my tank stock there the other week and I'm wondering how often water can be changed in the tank. I used to do it once a week when I had only 4 fish in there, but I think that I might have to do it a bit more often now that I've got 10.

I did a water change last on Sunday (about 25-30%) and decided to check the stats last night and discovered a bit of ammonia in the tank (which as we all now just wont do). I was gonno go do a change but just glanced through the handbook I have and it say not to do more than a 3rd water change a week as it changes the water too much and that this will really upset the fish.

Anybody got any thoughts?. How often do people actually change their water, and by how much? (I know that a smaller tank needs to be changed a lot more frequently than a big one).

K

p.s. Also discovered last night that my snail was dead (he smelled something awful), I think I actually bought a dead snail!! He'd been in my tank for nearly two weeks, rotting up the place!!

 

[kris-b-]

You need to make your water changes regularly as trebling your amount in such a short space of time is a bad thing to do, your tank will not have the amount of bacteria needed to break down this bigger bio-load. You bacteria will now need to break down even more ammonia and nitrites and there would have only been enough to break down the bio load before you introduced your new fish.

You need to keep checking your water stats and perform regular water changes, your tank will more than likely go through a mini cycle with the increased bio-load, resulting in the fish being exposed to ammonia and nitrites which are toxic to the fish.

 

[Silverlady]

I wonder if the Ammonia rise was due to the dead snail.

 

[kris-b-]

The ammonia rise was more than likely because of the increased bio-load.

Say you had one fish in a tank, there will only be enough bacteria for the waste that fish produces, there wouldn't be a need for any more.

So when you treble your stock in such a short space of time the bacteria will need to grow to support the increased levels, and this will not happen over night. This is why introducing more fish very slowly to allow the bacteria to build up progressively is so important.

With the massively increased bio-load the fish will be producing ammonia and the bacteria will not be able to break it all down as there isn't sufficient amounts of them.

So please keep an eye on your water stats and keep up the regular water changes, even daily would be helpful to the fish.

The only reason water changes would harm the fish is if the temperature or pH of the water you put in your tank is extremely different to what is already in the tank.

 

[kakihara]

Cheers for that

I'll do a 20% water change every 2 days for the next week or 2 and check the stats every day in between also.

I never realised about the bacteria and possibly causing another mini cycle, I was more concerned about the filter handling the extra waste from all the fish.

On the topic of waste removal, how important is it to clean the gravel?

 

[rdd1952]

The number and frequency of water changes should be predicated byt your ammonia and nitrite readings. As already mentioned, you will almost certainly have a mini cycle. Test your ammonia and nitrite daily. Do water changes as needed to keep the levels under .5 at most. Hopefully, you can keep them near zero until the bacteria can catch up. It shouldn't take too long.

As for vacuuming the gravel, you should vacuum the gravel anytime you do a water change. Even now with the mini cycle, any waste you can get out will help in keeping the levels down.

 

[kakihara]

Sounds reasonable, though I'll have to take all the stuff out of the tank first to get a good run at the gravel. I hope that it won't disturb the fish too much!!

 

[rdd1952]

If the tank is heavily planted, you probably won't be able to do a real good vac. You just kind of have to get what you can. That is one of the downsides of planted tanks. You probably don't need to move everything around. Just get what you can unless it is really messy..

 

[SkiFletch]

Please forgive a non-brittish n00b here, but what does "Treble" mean? Last time I checked it was a musical term

 

[kris-b-]

treble = 3 times as much

 

[rdd1952]

Please forgive a non-brittish n00b here, but what does "Treble" mean? Last time I checked it was a musical term

treble = 3 times as much

In the good old USA, it would be tripled. I understood what was meant though. Our head golf pro is from England and speaks that "funny" English.