Quote:
Originally Posted by serratus
Wow, it seems you guys are unanimous about not using a mechanical filter and going for a good protein skimmer.
I'm starting to learn that the nitrates are bad too and live rock filters that out. Now, here is where I am a bit confused and please point out if any of what I am saying is wrong: Live Rock as well as a cannister filter have bacteria that grows in them that converts ammonia into nitrite and then from nitrite to nitrate. So from what you are saying, is there a different bacteria that grows ONLY in the live rock that converts nitrate into nitrogen gas? These guys don't live in the cannister filter?
Second confusing point, whether you have a cannister filter or not, the amount of ammonia produced by the live stock will be the same which means the amount of available ammonia that gets converted into nitrite is the same. In turn, this means that cannister filter or not, the amount of nitrite available to convert into nitrate is the same. So how does the cannister filter INCREASE the nitrate levels? Wouldn't that be the same irregardless of cannister filter or not?
I don't mean to sound like I am arguing with you. I am not. It's just that I am confused and would like to find out why. It seems that all of you agree that cannister filters INCREASE nitrate levels so there must be some error in my thinking and that's why I am confused.
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I'm running a sumpless 75 gallon at the moment, a 90 or 120 with a sump is in the future but for now the 75 is fine and running with a protein skimmer (old school air driven, counter current) as well as a Rena XP canister filter. I don't see anything wrong with your rationale with respect to the process of nitrification. Since you're very new to this, you don't come with any pre judgements regarding some of the equipment used and the processes involved in keeping SW tanks. I often see canisters given a bad rap and yes they can be a problem, but they can also work well. Live rock or canister will both do the job, but as mentioned, the canister is better run without filter media, except for carbon and perhaps GFO (granulated ferric oxide) for phosphate control. With sufficient live rock in your system, a canister is redundant as far as mechanical filtration, but in your case, as in mine, without a sump, a canister can add several gallons of volume to your system which is never a bad thing. It also adds a little extra flow but you'll definitely need some additional pumps/powerheads to keep things circulating.
When I first set up the tank (purchased used) the Rena canister came with it and the previous owner had ceramic media in it and not much else. Being a newb I read the instructions for the filter and proceeded to get all the 'proper' filter media to put in there, foam pads, more ceramic, plastic media, etc. etc. It really did get to be a pain to clean properly and after reading a little more on line, on forums such as this, I realized that it's best to run the thing empty, except for a bag of carbon. This is working well so far and after more than two years after setting up, my nitrates are undetectable. I must note, however, that from about the 7 month mark to 1.5 years after set up, I battled elevated nitrates. Also noteworthy is that there was virtually no change to these levels after I removed all the media from the canister. No matter what I tried, nitrates would return to between 20-40 ppm within days of a 30% water change. Therefore, in my particular case, I do not consider my canister to have been a 'nitrate factory', any more than my live rock. I really have no definitive answer as to why my nitrates are currently undetectable, my theory is, the tank has simply matured to the point where things are taking care of themselves in that regard. I also suspect the addition of first one and recently a second VorTech MP40W has contributed to cleaning up the nitrates. The greatly improved flow from these pumps is making life a lot easier.
So, based on my experience, by all means run a canister if you wish, but avoid filter pads, run it empty. For sure get a protein skimmer, even a crappy one will at least provide oxygenation, although you should be able to get a very good used one for a reasonable price, if new is too costly. Even if you are going FOWLR, don't skimp on the pumps for flow, it will aid the live rock in the filtration process.