Questions about filtration by lr and ls!

saltyrich

saltyrich

Active Member
Many recommend approximately 1.5 lbs per gallon of lr. and a 4-6 inch dsb to be effective. I currently have about 75-80 lbs of lr in my 30 gallon tall. The rockwork is great. It is slightly domed and extends to about 6 inches below the top of the tank. My dsb is 4 inches. I run an emperor 280 power filter without the filter pad in it just for additional circulation. Occasionally I put some carbon in to remove potential toxins and keep the water nice and clear (about 2-3 days a month). I'm I getting any substantial filtration gains by having MORE lr than what is usually typical?
 
javajoe

javajoe

Member
I would say yes. the more live rock, the more denitrifying bacteria you have to work with. It would be like using 2 filters instead of one, except safer. :)
 
hondo

hondo

Member
more LR = More filtration. You already have plenty why do you think you need more? don't get me wrong I'm never against adding more LR (I wish I could afford to) as it adds more life in the tank in addition to increasing your filtration.
 
fmarini

fmarini

Member
I'm no shark...
but I would tell you that having more live rock will provide you the "capacity" to have more filtration. Remember that live rock and live sand are nothing more than bio-supports for bacteria. In general terms your filtration is performed by bacteria, yes I know you have all kinds of sand and rock infauna which help reduce/digest detritus, but they don't breakdown organics to the same levels as bacteria.
So in a way you have the capcity to support more bacteria, but to me there is a point of diminishing returns. Meaning that you might not get maximal use out of it, because you placed all this rock into a small tank. This has the effect of decreased the total volume of water and potentionally limiting the amount of swimming space. Makes your fish less happy.
But with that said if you are happy w/ the setup... cool.
I wouldn't worry about, it sounds to me that you've got a nice setup.
Make sure this 280 filter doesn't have the biowheel or any filter pads in them, no need for any additional filtration.
my opinion
frank
 
saltyrich

saltyrich

Active Member
To clarify, I'm not adding any more lr. I'm discussing what's in the tank now. Some of the lr is denser than other pieces. It all looks real nice. Yes the water volume is reduced, however my fish inhabitants are rockwork fish anyway. My tomato stays with the anemone and the sixline wrasse, royal gramma, and talbot's damsel move in and out of the lr structure continuously. I'm just trying to understand my system as it stands now to the best of my ability. Another question - removal of the biowheel in the emperor. Why? Pros and cons? I dont run the filter pad as it is now. Should the bio wheel be removed?
 
broomer5

broomer5

Active Member
I'm sure someone has studied this before - but it wasn't me.
My thoughts ...
All lifeforms need energy to live, grow and reproduce.
Where they get that energy may differ, but nonetheless they still need it.
The nitrifying and denitrfying bacteria also need food.
I'm pretty sure that the size of the population of bacteria in a tank with live rock or anything, is limited by the amount of food ( waste in our case ).
Imagine a 5000 gallon tank full of the best live rock you could get your hands on.
No fish - no fish food - no wastes.
Let it sit in there for a long time - with the best water quality and circulation.
Everything is great.
Don't ever feed this tank - and I'd guess these bacteria start do die, no matter how much live rock's in there.
The space is there for them to live - but what are they going to eat for energy ?
So ....... I think the amount of wastes limits the bacteria population.
1.5 pounds in a 200 gallon tank = 300 lbs of rock.
Put 1 damsel in there, feed it modestly and let this tank run for a year.
How affective is all that rock going to be ?
How many bacteria can live on the wastes of this single fish ?
Is every pore, crack and crevis teaming with a huge bioslime of bacteria ?
Or has some of the bacteria perished - and left a void ?
Would this same tank with 3-4 fish, that is fed heavier, have more bacteria present ? In larger, healthier numbers ?
I don't know- just something to think about.
I think there's more to it than just 1.5 lbs per gallon and you're good to go.
Lots more to the equation than pounds per gallon.
Rules of thumbs - ya know ;)
 
saltyrich

saltyrich

Active Member
Then let me ask this. The tank is stocked with plenty of inverts and coral, as well as 4 fish. I'm probably just a shade over the recommended bioload, but not much over. All of these critters get fed. I feed fish every 2-3 days. Same with the coral. Inverts scrape up the leftovers. Would such a stocked tank support the bacteria on the extra lr? Does extra lr increase the biolad capacity?
 
broomer5

broomer5

Active Member
Yes - more live rock mean more surface area for bacteria to grow on and in.
Does it mean you are in any better shape than a person with a tank that has half as much live rock ? Don't know.
If your ammonia and nitrites are zero - you have adaquate nitrifying bacteria.
If your nitrates are through the roof - you probably have too high a bioload. Especially if you find them climbing after a substantial waterchange with nitrate free saltwater.
If your nitrates are low - the amount of rock, and your sandbed is kicking arse !
The test results will tell you what you ask.
 
jumpfrog

jumpfrog

Active Member
Not an expert here either but I think you're right. You have capacity (more ability to provide for larger bacteria populations) for a substantial bioload. The question is: Is it enough. I think as broomer said. If your readings are zero then you have accomplished your goal of system stasis.
I imagine if you increased load, your system would adjust back to zero. Therefore you have more capacity.
Sounds like you have your bioload well in hand. Without some specific experimentation I don't know if you'll ever have a "perfect" answer to your question.
Good Luck and happy reefing!
 
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