Filter Bacteria

[PrairieSunflower]

So... I got to thinking and confused myself.  HAHA
 
I change my tank water every 3-4 days (between 25-50% at those times).  My thought has always been that clean water is best and there would never be old tank syndrome if they always had good clean fresh water.  But... now I've been thinking... with a possible long holiday in the future and thoughts on leaving the tank for about 2 weeks without a water change (no one around able to do it during that time)... something occurred to me....
 
If I am changing the water that often... does it affect the amount of bacteria in my filter... by that I mean, if I am changing my water more and thus removing the ammonia really quick... is there therefore less bacteria in my filter?  AND... am I maybe better off gradually changing that to longer times without water changes so that going away for a holiday wouldn't be a big deal for my fish?

 

[coolie]

I think you would have to have an extremely heavy ammonia production rate - over crowded and large fish for this equasion.
 
What I mean, is such an emormous ammonia "load" that it's only being kept down by your water changes, but I can't see that somehow.

 

[CezzaXV]

Are you cycling, or are you talking about in an established tank? In an established tank you should never be removing ammonia because there shouldn't be any, you will be removing nitrates.

 

[the_lock_man]

There's always going to be some ammonia because the fish are constantly producing it and there will always be a tiny amount that hasn't yet reached the filter. But this is such a small amount it wouldn't make a difference.

 

[PrairieSunflower]

It's an established tank.  I think I really fear leaving them longer than a few days without fresh water... I'm not having any trouble with ammonia readings or anything like that... but just got to wondering if my filter could house more bacteria if I wasn't changing the water so much.

 

[HAMBONE]

Here's my take on fish keeping..
 
Change aboot 25% every week to ten days.. Your tank should smell like a pond when you put your nose to it..
 
In my opinion you're changing your water too much..
 
All three of my tanks smell like ponds, they are all heavily planted and all has duck weeds.. and algae
 
this approach works for me and my fish seem to be happy and healthy save for the cammallannuss worms I am fighting my 37 gallon, but those came from some angel fish I got from my LFS...
 
I am winning that battle..

 

[PrairieSunflower]

My platy tank (with just a few juveniles and a lot of cabomba) has a nature smell to it.  My larger tank doesn't smell of anything.  I will start dropping back to less changes.
 
My stocking is...
 
In my 10 gallon: 6 juvenile platies (one to be re-homed).
In my 20ish gallon (slightly more than that), I have 12 neon tetras (started losing some to NTD again), 2 platies, 6 guppies (all livebearers are empty/virgin females) and thereabouts 20 cherry shirmp.

 

[coolie]

This thread is actually making me feel guilty - I don't even change my water as often as the people telling you to slow it down. Mind you - I only have a few small tetras, but even so.

 

[PrairieSunflower]

I didn't used to clean so much.... but last summer I had a major unexplained tank disaster (with so many symptoms I couldn't even figure out what was going on and all the fish died... 2 were rescued early on from the tank and are still alive today).... I just have kept things as pristine as possible since in fear something would happen.

 

[CezzaXV]

Your filter will house as many bacteria as it needs to to deal with the ammonia being created, and no more than that. Water changes are irrelevant. While the_lock_man is right in that there will always be a very small, undetectable amount of ammonia present as it may take a little while before the bacteria get to it, it's negligible amount and your water changes won't have any affect on that ammonia or the bacteria.

The main thing with water changes is nitrates. The rule of thumb is that you shouldn't let your nitrates get 20ppm higher than what comes out of the tap, so you can adjust the size/regularity of the water changes in accordance with that.

Fish will still get sick and disasters will still happen no matter how many water changes you do. All you're doing is making extra work for yourself.

 

[TwoTankAmin]

This is a first for me in 13+ years of keeping fish and having 16-20 tanks running most of that time.
 
I used to say I never heard anybody claim their water was too clean in a FW tank until this thread. I urge anybody reading this thread to ignore anything which tells you not to change your water regularly. If you want to try a well planted very lightly stocked Walstead tank that is an exception. But then the ecology of this type of tank is designed to replace most water changes.
 
I have been doing weekly changes of 35-50% religiously for a long time. It has never harmed anything.
 
You can also have more bacteria than you need in a tank. especially over a several week or month period. The bacteria can survive without ammonia or nitrite for some time if they have to. So if you have a tank which is cycled for a greater capacity than you put in, the bacteria will not just drop dead, they will take some time to adjust downward. There is also evidence that the bacteria are able to increase the amount of ammonia or nitrite they can process before they need to reproduce.
 
If you have a tank working fine and you remove some of the stock, there will be more bacteria than the new bio-load requires, but the bacteria will not just drop dead, they just get a bit less food. If the drop is enough, eventually the colony will adjust down in size.
 
The nice thing here is the bacteria colonies can grow faster than they will shrink. So when there is excess ammonia they can catch up fairly quickly but when there is less ammonia they wont vanish anywhere near as fast.