Water Change After Cycle, Why?

[rkpetersen]

The bacteria start decreasing their growth, reproduction and numbers as soon as a source of new ammonia vanishes. You can't maintain a biological filter without either something living, something recently living, or artificial means like ammonium chloride.

 

[davidcalgary29]

If the above is true — I will have no livestock for months — how much ammonium chloride should I dose per gallon, and how often should I do it?

 

[lapin]

Depends on the concentration and how much bacteria you want to keep alive.

Dr Tims ammonium chloride:

*NOTE: As of November 1, 2016 we changed the concentration of the ammonium chloride solution so it now takes 4 drops per gallon. The previous version called for 1 drop per gallon. Please see the label on your bottle to determine how much to use. If the bottle says use 1 drop use 1 drop if the bottle says use 4 drops use 4 drops.

 

[davidcalgary29]

This is a criticism of no one, but I keep information (which is in itself often contradictory) on this site and others about post-cycle bacterial activity that seems to be based on anecdote rather than scientific fact. In just two threads so far, I've been advised that: your tank will uncycle without fish; it will never uncycle, irrespective of load; bacteria must be constantly fed; and no, they don't.

I will dose ammonium chloride at the rate of one drop a week once my nitrates drop to 0 because I have macro and don't have access to any other way of dosing nutrients at this time. And after reading through multiple websites, I can only surmise this: once cycled, a tank can't "uncycle". Bacteria may become dormant, and it may take some time for them to reactivate and multiply. This is why it's important to add fish slowly so that the bacterial load has time to multiply to adjust to the increased bioload. If I'm wrong here, please correct me (with a reasoned scientific argument).

 

[gbroadbridge]

It is certainly not a must. It just means more nutrients to deal with (and maybe reduced alk), but if you have that under control, its fine.

Realise I'm new to this forum, but I have had a couple of sucessful reefs in the past.

I've always done the 30-50 percent water change at the end of a tank cycle to reduce nitrates.

This time around I decided to save salt and water by using Carbon dosing to reduce nitrate.

The result was not expected.

I ended up with a thick slimey bacterial growth everywhere which I guess was due to excess carbon, even though nitrates were not dropping. It was not phosphate limited. It was limited by something, but not nitrate or phosphate.

I also had extremely cloudy water like a bacterial bloom.

I took away the carbon dose and the bacterial growth went away in 2 days.

The cloudy water persisted, but after a 30% water change went away.

I wpuld love expert opinions as to what happened.

I expected dosing a carbon source would wotk as advertised, but in this case it didn't. What else could limit the effect.
This was a very new tank less than 28 days, but I was following methods that have worked commercially in the past.

Regards Graham.