Fishy cycling and water changes

[Chikadee]

I have heard two contradicting things about this. Some people say that it is a bad idea to do large water changes while cycling (fishy cycling) because the tank will never entirely cycle and the ammonia and nitrites need to "spike" in order to completely cycle the tank.

I have also heard that you should do large water changes to keep the fish alive, and this will not slow down the cycling process because any detectable ammonia/nitrites will be enough to promote and maximize bacteria growth.

I'm curious as to which one is correct? I was under the impression that you should do large water changes to keep your fish alive and this will slow down the cycle a little bit but not by much...

 

[astroguy]

I once believed the first option to minimize the water changes to make cycling quicker.
However, I recently cycled my 29g performing large (25-30%) water changes almost daily
to keep the concentrations low (it never reached above 0.5-0.75ppm), and after only 3 weeks,
today, the tank has just cycled.

So, I guess that you can do frequent water changes. Note, however, that you must make sure that you do not have too many fishes or food, as this will increase the load of ammonia/nitrite.

 

[malkore]

30% is not a 'large' water change.

Anyhow, what you need to do is change enough water, frequently enough, to keep your ammonia no higher than .25 ppm, and nitrite below .5ppm.

If ammonia is up to .5ppm, you probably need a 50% water change to get it down to .25ppm.

When doing these water changes, you don't need to vacuum the gravel each time...just once a week like a normal water change.

 

[jsoong]

The current "wisdom" out there is that by lowering the levels with water changes, you slow down the cycling process. However, with fish in the tank, you pretty much have to keep the levels low or the fish die.

From reading the threads here, it seems with fishless cycling, and allowing the levels to peak, people are finishing cycling at 2-3 weeks. When I did my fishie cycling & keeping the levels low, it took some 6 weeks.

But then, better a slow cycle than dead fish!

 

[Endgame319]

I dont do any water changed during the cycle, Its better to have a short, harsh experience than a long painful one. But I only use very hardy zebra danios while cycling.

 

[deli_conker]

I haven't done a fishy cycle for a very long time, but I would do very frequent yet small water changes. I wouldn't let the ammonia get past a certain point.

The bacteria will still form regardless and over time will be able to handle the bio load of the tank (assuming it's not overstocked). As far as I know, any amount of ammonia will start the cycle; you don't need high levels before the bacteria start to grow. Following that logic, I believe that keeping the levels down for the sake of the fishes health is more important than trying to speed the cycle up by having greater concentrations of ammonia.

However, in a fishy cycle, the fish are going to feel the burn either way. It's not the 80's anymore. We have fishless cycling and bio-spira. I always suggest either of those along with media or gravel from an established and healthy tank. My lfs has no problem giving a handful of gravel to new aquarists...

 

[snifflyfro]

My lfs actually gave me a bunch of filter media. You need to be careful that you are positive that the tanks at the lfs don't have a disease, but if you are then it's great. They don't just offer it away, but I asked for some gravel and they said they've got some better for me.