Tank cycling ammonia at about .25 or so. Water change?

[Jerdel]

How high should I let the ammonia get while the tank is cycling before I should do a water change? I got alot of hitchikers on the live rock I bought that I really dont want to die.

[chefgreg]

Leave it alone, if you do a water change it will slow down the process. If you aren't in a hurry then have at it.

[jerpa]

If you are attempting to save the hitchikers you should do water changes. It will slow the cycling process slightly but will result in stable tank sooner than not doing water changes and killing all the hitchikers. I'm sure many will disagree with me. If you search the forums for water change during cycling you will find a recent thread that goes pretty in depth.

[blt]

Originally Posted by chefgreg

if you do a water change it will slow down the process.

A water change will NOT slow the process. The bacteria doesn't multiply faster at 1 ppm ammonia than it does at 0.25 ppm. It multiplies at the exact same rate for anything > 0 ppm.

To the OP: I've seen recommendations to start water changes anywhere between 0.25 ppm and 1 ppm (assuming sand, rock & hitchhikers only). The most common seemed to be around 0.5 ppm. This is 2nd hand knowledge though, I don't have enough personal experience to know if that's actually the sweet spot or not.

[jerpa]

Here is the thread. It will answer your questions.
http://www.reefcentral.com/forums/sh....php?t=2093085

[Jerdel]

Thanks everyone

[Randy Holmes-Farley]

The bacteria doesn't multiply faster at 1 ppm ammonia than it does at 0.25 ppm. It multiplies at the exact same rate for anything > 0 ppm.


How do you know that?

[blt]

Basic biology. The bacteria will multiply based on the availability of space (that has favourable conditions) and food. Any amount of excess indicates that there is more than the current amount of bacteria can consume - they aren't going to consume more food if there is a larger excess. The difference comes from how soon the bacteria colony will outgrow that excess - something that can be mitigated by by having a slow, steady source of ammonia import (be it adding a bit of fish food or household ammonia) as opposed to letting it spike.

There may be some variations in growth rate at very low ammonia levels (still > 0) due to the amount not necessarily being uniform through the entire tank, but you'd have to have some pretty bad dead-zones in your tank's circulation for that to have an impact at 0.25ppm.

Now, I will admit, this is basic biology. If there is more advanced research out there that indicates this doesn't hold true for the kind of nitrifying bacteria found in marine aquaria (entirely possible - the difference between basic and advanced theories can sometimes be drastic), I am unaware of them and would definitely be interested in hearing about them.

[Randy Holmes-Farley]

Basic biology. The bacteria will multiply based on the availability of space (that has favourable conditions) and food.

OK, so I guess the answer is you do not really know, just like me.

Unless you have experimental data indicating what level of ammonia is growth limiting, and some nonzero level certainly is too low for optimal growth, you cannot answer the question about how much you need to have before growth is limited by availability of ammonia.

[thegrun]

So I guess what grandma used to say "If you want to preserve as many organisms as possible and still have a robust cycle, make water changes if your ammonia gets over 1ppm" still holds true.

[Uncle Salty 05]

If you do a water change and lower the ammonia level, you will also lower the number of bacteria needed to process that ammonia, thus reducing the carrying capacity once the cycle has completed.
I would recommend that you not do a water change until your nitrites read zero.
If you are at .25 and your hithikers are still alive, I don't think you need to worry.

[aleonn]

I'd do a water change to make the hitch hikers more comfortable.