New Tank Questions - Stocking, Cycling Etc

[waterdrop]

Our fishless cycling article was arrived at by rdd1952 - I can't speak for him, but I believe he was trying to pull together several variations that were being discussed on TFF and he had read pretty widely among the different versions extant on the net. In my own opinion he did quite a good job - making a nice line between various extremes of going into too much detail vs. not saying enough about how to do it. RDD himself has discussed various bits in more detail in various threads over the years and they are out there to be found. He says somewhere that getting the populations up to the size where 5ppm ammonia and its resulting nitrite can be processed to zero within 12 hours means that a full size stocking, in fact an overstocking, can be safely introduced immediately without worry of overtaxing the filter.

In my experience hanging around the "New to the Hobby" forum and in discussions, I believe, of MW, BTT and some of the others, this "qualification" of the filter seems to have turned out to be quite a nice number. It really does give you a good shot at a stable filter even if the stocking is large, and regardless of the stocking size it helps you to hold off until it is not likely the populations of bacteria will falter and give you a nasty surprise. Its good to remember that its just a "point in time" and that the filter will continue to mature and get more stable for a full six months or more.

Another thing to remember is that its good to continue on for one more week after reaching this "qualification point" and then make the big water change and introduce fish. If you truly will only introduce a 25% or 50% stocking and are getting very consistent 5ppm to 0ppm drops that are taking just a little more than 12 hours, then even rdd has been known to say its ok to go ahead and make the change to fish. The really nice solid standard, however, has been to make sure 5ppm of ammonia and all the nitrite it produces can drop to zero within 12 hours and then to make sure its repeats that every day for a full week, or the better part of a week.

~~waterdrop~~

 

[Miss Wiggle]

i agree with WD, we discussed it in the scientific section a few months back in some detail (link) and the general conclusion is while you can push it and stock when the nitrites are dropping in a bit over 12 hrs and you may well have sucess doing so, it's that bit safer to wait until the 12 hr mark. When you've been that patient to get all the way through cycling it seems a shame to spoil it by not having 1 weeks more patience.

just look at the bigger picture, once a fishkeeper always a fishkeeper, chances are you'll have tanks for most of the rest of your life, in that context whats waiting a couple of weeks more to make sure you have a safe easy start?

 

[jnms]

Thanks for the replies waterdrop and Miss Wiggle, that actually makes a lot of sense. I have read the thread you linked to Miss Wiggle and it is very useful information. I have actually posted a question over there - or more of an observation really...

Regarding my cycle. At the moment it seems that where my tank was processing ammonia down to 0 in 12 hours, it is now only processing down to around 0.6 in 12 hours. I have a new test kit arriving shortly so I will use that to confirm these results. However this seems a little unusual at this stage in the cycle doesn't it?

 

[Miss Wiggle]

it can happen, WD made a v good post earlier today about a cycle not being the linear process that we sometimes think of it as, I'll find it and show you it as I think it'll probably answer you better than I can!

 

[Miss Wiggle]

here we go

You may be slipping into the minor confusion of equating the cycling process with a smooth, linear chemical reaction. The process is not smooth. The bacteria are individual cells, each of which has a "lag phase," a "growth phase" and each of our two bacterial species have different curves for these and process different amounts of materials. When we come along and take a "crude snapshot" of the situation with our little reagent tests, we tend to project a lot more knowledge on to our tidbit of information about the colonies than we really have.

In addition to this there are two more factors to consider

1 - variables - this is a big broad category and basically encompasses everything, in a newly set up that there are a lot of things fluctating, not just the cycling process but things like the substrate and new decor leeching stuff into the water, all sorts of minor chemical reactions are going on as the tank settles down. We can't test the vast majority of these and really have no reason to do so, but what it means is sometimes the cycle will not perform as expected and I suspect if we could measure all the other things going on (and also had a much more detailed knowledge of the environment that our bacteria need to thrive) then we'd be able to pinpoint exactly what it is that made this happen. But the simple fact is right now we can't measure everything that's going on which means sometimes things happen which we can offer no explanation for, but just say 'it happens in enw tanks sometimes!'

2 - the other thing to think about is the accuracy of our test kits, yes they're relatively good for the money we pay and for our purposes, but this is not lab grade equipment, it does just go wrong sometimes and as we've all moaned on a number of occasions the colour charts are bloomin hard to read and you can just misinterpret what the test kit is saying to you. the difference of 0.1ppm is really not that big a difference and easy for a £15 test kit to get wrong.