greggw2gs
New Member
Majjie, I realize your post was 16 years ago but I found it very enlightening and still of course very useful. I also agree that surface area size and agitation are just as important if not more so than the bio engine in your filter. I had a thought and would love your views on a different way to go about the fishless cycle. I have been using Dr. Tim's Ammonia but like everyone else have been doing my doses in a single session. So if I needed to add 20 drops I would add 20 drops simultaneously. I wonder if the amount of Ammonia should be broken down into say two 12-hour doses to help mimic a real environment where the fish produce Ammonia throughout the day not all at once. Would this help the bio engine be more resilient?I've been thinking about this
Surely all the fish in a tank can only produce ammonia (NH3) from the food they eat.
A small tub of dry fish food contains between 20 and 50g food (TetraMin/Interpet Liquifry powder)
The protein content is between 44 and 47% (on my 6 kinds of dry food) - lets say 50%
The average nitrogen (N) content of a protein is 16% (check on Google)
Lets say, for the sake of argument that you put 300mg of food into your tank a day i.e. a small tub of TetraMin would last just over 2 months (just for that one tank) - worst case scenario!
50% is protein and 16% of that is N - total of 24mg N per day
The fish are going to use most of the N (a turbot apparently only excretes up to 7.5% of dietary N intake as ammonia) - but lets assume that tropical fish are horribly inefficient and only use 50% of their food N. 12mg of excess N per day is available to make NH3.
Now lets look at the filter. During fishless cycling we put household ammonia into the tank (or, at least I do). When my tanks were fully cycled they could remove at least 10 drops of household ammonia from the tank overnight (15hours). The household ammonia is a solution of 9.5% NH4OH. Lets assume that a drop is 0.025ml (it's probably bigger) - that means that the filter can remove 23.75mg NH4OH in 15 hours, or about 38mg per day. 38mg of NH4OH contains about 15mg N (molecular weight 35/atomic weight 14).
Conclusion: the filter is more than capable of dealing with all the NH3 that is likely to be produced
Unless your fish are chomping thru the whole plant content of the tank each day (low protein content in vegetables!); lots of plants/snails/fish are dying each day; you're chucking in a whole tub of food each day; or you kill off the filter bacteria in some way - the capacity of the filter is unlikely to be a problem
I've always believed that it is the oxygen carrying capacity of the water that is the limiting factor on stocking levels, not the filter - hence the limit of 1in. fish per 12 sq.in. surface area. I know a lot of you on here will disagree, though. I'd never heard of the 1in. fish per US gallon rule before I joined here - by that measure all my tanks are overstocked
Thanks Gregg
