FishProfiles.com Message Forums

Is there any way a canister filter could be used?

My water volume has recently doubled due to alterations in stocking and the internal just won't provide enough turnover. I have a canister doing nothing and although it'll only do 10x/hr it is better than what is currently there. (I know that it should be closer to 20, but since these guys spend a fair whack of time in still pools, I'll try 10 to start with and just make sure they aren't being blown around the tank. I can always increase it if needed.)

Every time I say canister, however, people recoil in horror and use words like 'nitrate factory', which doesn't sound like a good thing. Myself, I'm failing to see the difference between that and a HOB, which doesn't seem to bring about the same reaction. Why is one evil and one recommended, especially when the evil ones has so many more options when it comes to media?

Have you done it?
Can it be done?
If yes, what are the pros and cons?

For animals, the entire universe has been neatly divided into things to (a) mate with, (b) eat, (c) run away from, and (d) rocks. - Terry Pratchett

You can use a canister if you like, but it easily can become a nitrate factory. So can HOBs. So can ANY type of filter media that doesn't get a thorough clean out weekly.

If you want to use a canister, go for it. Just be sure to clean it out regularly. I'd personally have two sets of mechanical filter media. Whenever you clean, swap out with the filters that haven't been used, and put the ones that were used in fresh water for a day after thorough rinsing, then let completely dry until it's time to use them again. This method will prevent the mechanical filter part from harboring bacteria.

However, you don't have a full load of live rock as I recall, so you will want some of the filter dedicated to processing nitrogenous waste. I'd use a section of bio rings in the canister, just swish these out in the tank water you pull out with your water change to remove excess debris.

If you have other sections, you can run whatever type of chemical media suits you, or keep some live rock rubble in it to house pods and whatnot. Up to you. Just keep this stuff cleaned weekly as well.

Oh I s'pose the pros would be that a canister is nice and big, lots of room for media etc.

The cons would be that it is tough to clean out. It's big and bulky usually. Also, there's enough water in one of these things that it makes a difference on small tanks if you fill it with anything but the right salinity water. Add the need to clean weekly and you have yourself a small water change right there.

---

Critical Fertilator: The Micromanager of Macronutrients

I do like the idea of an insta-WC with the cleaning I am thinking of what a colossal hassle it is to prime that filter too. Still, I'll give it a go

What type of mechanical would be least problematic? A coarse sponge or two? I suppose it doesn't really matter, debris is debris regardless of where it is in the tank. Do any types become problematic faster than others?

And *sigh* the bloody evil pink rock is growing on me. It has gone through a fuzzy stage and out the other side and has now sprouted little red ferny plants that are rather attractive. I swear it has changed colour too, it is a much deeper pink than when it arrived, and I think it has more stuff on it. The naked side looks less ugly. So I suppose I could add a bit more...

How much would you consider a full load of LR? Is there a percentage rule of thumb that I should aim for?

Why would I not want bacteria growing on the mechanical media but I would want it on the biomedia? Does the mechanical lend itself to the anaerobic stuff or can I have too much of a good thing or is there some other reason?

I'm just Little Miss Questions tonight, sorry.


For animals, the entire universe has been neatly divided into things to (a) mate with, (b) eat, (c) run away from, and (d) rocks. - Terry Pratchett

When it comes to the nitrate factory theory, the idea is that you have so much surface area for aerobic bacteria, that ammonia is pretty much instantly turned to nitrate.

This is a good thing in fw systems, as there's not really a better way for things to happen. In SW systems, the LR gives a better, more natural way of things to happen that doesn't end with nitrate. In the deep parts of the rock, anaerobic bacteria will make use of the wastes and convert nitrogenous wastes into nitrogen gas. It's happened many times, and is easy to show experimentally that a tank with lots of live rock simply has less nitrate given everything else is equal. I assume it might also have to do with some of the interesting life forms on the surface of the rock too. Sponges, macro and micro algaes etc.

so....yes, too much of a good thing I suppose. You just want your LR to handle as much as it can. It will make for a healthier tank.

Anyhow, most people like to call 1 lb per gallon of tank capacity sufficient for bio filtration to be completely handled by the rock. A lot of people like closer to 1.5 or 2 lbs of rock.

For the cannister the only thing to remember is that a finer sponge will clog faster, but I don't think it will matter in a week's time, and that's about as often as you should clean the filter.

Oh and I *told* you that you'd like the LR. That's the fun of LR it does change according to your setup. It's like it's almost....alive

---

Critical Fertilator: The Micromanager of Macronutrients