Tank crash possibility?

I thought flow of the water was brought through by what filters you are running?

 

You want to create a lot of flow through the tank you really want to move the water because the water flow through the Live rock is really important to the biological filtration of the tank . In a mature reef tank the Live Rock becomes your main source of biological filtration. The filter media and skimmer are mechanical filters and a carbon reactor or phosphate reactor would be chemical filtration etc. Also good flow in the tank is important because in areas of the tank that do not get enough flow algae of all kinds (cyano red slime etc) will start to take over.

 

I have heard others say this, and I'm NOT speaking from experience, so take what I say with a grain of salt. From what I've learned, nitrifying bacteria are colonizing in great numbers during the cycle in response to a large amount of ammonia, then nitrite, then nitrates. True, the bacteria are not multiplying in the water, but on all available surface areas in the system. Of this much I'm certain.

With this being the case, wouldn't a water change, removing ammonia and nitrites, prevent the further colonization of the very bacteria we're trying to harbor? At the very best, would it not slow down the exponential growth of these bacteria in response to their food source--since removing water is tantamount to removing their food?

I don't understand why people say to do water changes during a cycle, but I've heard it many times, and the notion is completely counterintuitive to me.

I wouldn't remove food for bacteria that I wanted to flourish; so I would never change water during a cycle.

I would appreciate any information to the contrary.

 

As with most things in life, how things look often depends on where you are standing.

When cycling a new tank without any fish (or maybe just an unfortunate damsel) doing a water change will decrease the food supply of the bacteria that you are trying to get to multiply. Theoretically, a big enough or frequent enough water changes could reduce the nutrient supply enough to slow or halt the bacteria multiplication. I say theoretically because in most circumstances, nutrient supply is not the limiting factor in bacteria multiplication (time is). Your are trying to get to billions of bacteria and it just takes time for 1 to become 2 to become 4 etc...

If you are in the unfortunate situation of having fish in your tank while it is cycling you might find that you have levels of ammonia or nitrates that are an immenent threat to your fish. In this instance doing a water change is the fastest way to reduce toxic levels in your tank and my allow your fish to survive long enough for the cycle to finish. In this instance, there is plenty of nutrient for your bacteria and even a 50% water change should leave plenty to power the continued growth of your bacterial colonies.

Hope that helps.

 

Nicely put. Thanks.