Live rock filtration

[finarfin]

Hello all in the brackish community! Just posted in the intro forum, thought I'd follow it up here! I'm about to set up a new 30 gal brackish tank - previously had a range of marine and f/w tanks but always wanted to try brackish.

First question - do bacteria come in fresh or salt water varieties?
Seems a funny way to start, but please bear with me for now. If I was setting up a new reef system, then I wouldn't be looking into undergravel or power filters (as I was using 10 years ago) but instead setting up a live rock system. The main benefit of this form of "filtration", I believe, is that live rock comes complete with a full complement of both nitrifying and de-nitrifying bacteria.
Now onto the second bit - to set up my brackish tank is there any reason why I don't use live rock? OK, so the "surface inhabitants" wouldn't survive, so the first thing to do would be to thoroughly clean the surface of each rock to remove any potential source of decay. I then just add the cleaned live rock, which are still packed full of helpful bacteria, to the tank.

Hey presto I have a brackish live rock filtered aquarium ready for its first inhabitants :)

Now in practice I'd probably run the system with an already matured power filter (a Biolife 55) for the forseeable future, and as insurance, but as a future project, is it worth a try:huh:

Perhaps this could be taken further as an idea - using existing tanks to mature any pieces of porous rock (I have a lot from my marine days) as ready-made filters?

Would this even work with f/w tanks, again using pieces of rock placed in an existing tank to mature for a few months to make "live" rock filters?

This should work, as all the marine guys do it and rely on live rock to remove nitrate - so surely it should work just as well in any other kind of water???

Be pleased to hear from you all!

Andrew.

[Pufferpunk]

FW & SW nitrifying bacteria are 2 different organisms. The FW bacteria dies off around 1.012. The SW bacteria & other organisms in LR will not survive at BW SG.

[cyborob]

Oh good topic!

So I have a question in the same area.

I've just moved my puffer from a 20 long to a 40 gallon and put in about 12 pounds of moon and lace rock.

Will this rock turn to live sw rock at the point past 1.012 then???

[Pufferpunk]

Mmmm... not really. SW bacteria will develop in/on the rock but I wouldn't actually call it "live" rock. The "creatures" in SW LR (tubeworms, pods, etc.) can only survive in SG of around 1.018 (maybe even higher, I'm not absolutely sure) & would have to move over from real LR, origionating from the ocean.

[cyborob]

So at 1.018 or above one would then add some live rock from the LSF and presto full SW tank?

[Pufferpunk]

You got it! A lot of time though, the LR from the stores isn't fully cured yet, so it's not a good idea to put it into a tank with fish in it. Too much die-off & then the tank is cycling again.

[cyborob]

You got it! A lot of time though, the LR from the stores isn't fully cured yet, so it's not a good idea to put it into a tank with fish in it. Too much die-off & then the tank is cycling again.


Oh it's always something, grrr!
What do you do with it then before you can put it in with your fish?

[Pufferpunk]

Well, the best way to cycle a new SW tank, is with LR. If you already have an established tank & want to add more rock, you'll have to cure the rock in a bucket, or swperate tank. If the rock is totally uncured, (taken directly from the ocean & never cured anywhere), I have put it into a vat, with a skimmer & powerhead on it. Lots of info on this kinda stuff here:
http://www.marinedepot.com/aquarium_marine_depot_educational_newsletter_artic les__index.asp

[cyborob]

Very Good, thank you!

[finarfin]

Thanks for the info so far. I have a lot of "old" coral rock, taken from my old marine tank, so I'll probably use this is the brackish tank. It should develop it's own bacterial colonies eventually I guess! The Biolife 55 is presently being used in a f/w tank so that should be fully matured to use in the new tank.

I guess that at some point many months down the line, if i took the Biolife out the rock should have fully matured enough to filter the tank by itself - but I'm not sure if I'd be brave enough to try that with whatever stock I have at the time!

[Pufferpunk]

Maybe but I'd think to have a natural filtration system, you'd need lots of plants & good flow.