natural filtration...

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Aquarium Advice Apprentice
Apr 30, 2006
Ok, we've got a 75 gal salt water fish tank running with only live sand and is nearing the end of the cycle.

What is the best 'natural' filtration system to do? What I mean is, I don't really want to have filter machines and pumps and stuff hooked up.

So what is the best way to do it? Is it to just have a ton of live rock (figuratively speaking :p)? or have to build a fuge?
if you want to run without a filter, that is fine, there a ways to do that. however, running without any electrical equipment is not going to work.

without a sump, you will need:
1.5 to 2 pounds per gallon of live rock. the amount of space this rock will take up in your tank will depend on the type of rock you buy.
a skimmer.... yes, you will need a skimmer, unless you are willing to do daily water changes to remove proteins from the water.
powerheads... you will need water movement in the tank to simulate the ocean's currents, and to prevent algea and cyano from building up on your rocks. try to aim for 10 times your tank volume as an hourly turnover rate. i.e. a 75 gallon tank should have 750 gallons per hour water movement.

if you go with a sump, you can ditch the powerheads and use your return pump for water circulation. make sure that you look at the flowrate vs head curve to determine if you have adequate flowrate once the water gets up to the tank. another thing you can do if you have a sump is section off part of it as a refugium. you can use macro algea in there to remove some nutrients from the water.

be advised, if you do add live rock to the tank, it may induce a small cycle due to die-off from the live rock. i would not add any livestock to your tank until you decide what you are going to do for filtration. also, how much sand do you have in your tank? are you planning for a deep sand bed?

What is considered deep sand bed and what are benefits?

I think we've got almost 2 inches of sand/crushed coral in there now and will be acquiring a little more soon.

We will still go with powerheads for circulation.

Live rock will be added soon as well locally (malkore)

Currently, we've got a biowheel running with mechanical/chemical? filters to try and clear up the water.
as long as you stock your tank lightly, keep good maintenance and don't over feed you'll be just fine. My 55 is "filterless" I have 3-4 inches of CC/Sand and I forget how much rock, probably 100 pounds or so. That's my filter. i run 2 power heads and a closed loop pump for circulation. I have a whisper hob filter on my tank, but it is only there for the occasionaly bag of GAC. There are no filter elements in it. My tank has been runing this way for 3 years now.
My tank is almost the same as Billy's. I have a 55g reef with 3" sandbed, 100+lbs of liverock, four powerheads and a skimmer. It houses a pair of maroon clowns, a pair of watchman gobies and a lawnmower blenny. This tank has been running for about 2yrs (was originally in a 110 and moved so it's actually around 4yrs old). I have a 44ghex with a shallow sandbed, 50lbs of liverock, skimmer and hob filter that holds liverock rubble that's been running for 1+yrs. Home to a pair of perc clowns. Then I have a 10g nano with 15lbs of liverock, barebottom tank and hob with rubble that is about 2yrs old and houses one black female perc.
I think liverock, as expensive as it is, is the best filtration you can have on your tank. It's simplistic, beneficial and attractive. Then the addition of a skimmer is always a good idea.
I see, will be getting live rock soon.

How long will it take for base rock to become 'live' if 60 lb live and 60 dead are added to the live?
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