RSS Does the surface area of live rock really matter?

Discussion in 'RSS Feeds' started by MASA Admin, 4 Nov 2014.

  1. MASA Admin

    MASA Admin Moderator

    Posts: 10,000
    8 May 2007
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    The reef aquarium hobby is a past time of expendable income and mental bandwidth;  this explains why even though the focus is supposed to be about reef life like corals, fish and inverts, we get sucked into long esoterical discussions about live rock types, surface area and available “internal pore network”.

    As a hobby it’s totally fine and welcome to spend time splitting hairs over the minutiae of one’s own passion and hobby, but as this video clearly shows, we’ve gotten so far off from the substantive part of the discussion, that the simple, logical conclusions are not being made. Yes of course the surface area of live rock and aquarium rock does matter but probably not at all in the way that the topic is discussed by reef aquarists, and not exactly in the same vein as what Bulk Reef Supply presents herein.

    [​IMG]In their investigative reporting, Bulk Reef Supply wanted to find out which kind of rock used in reef aquariums is the most porous. Thankfully BRS included a sample of MarinePure biomedia, formerly known as Cell-Pore, to help us deliver the real conclusion to their investigation.

    In conventional marine aquarium wisdom, an aquarium needs a lot of surface area in the filter and in the tank in order to house beneficial aerobic and anaerobic bacteria for biologically cleaning the aquarium water. The logic goes that more surface area equals more beneficial bacteria equals more-better-faster processing of nitrogenous wastes such as ammonia, nitrite and nitrate.

    What we find greatly amusing is that the “challenge” of sufficient surface area was completely overcome thirty years ago with bioballs and a deluge of creative high surface area objects. Then in the nineties we figured out that the bioballs were working too well in their wet-dry environment and we removed them allowing the live rock to shoulder the burden.

    When the bioballs were exiled from our aquarium, again there was this overly cautious discussion of how much to remove, how fast and whether the tank would “survive”. Needless to say, no reef aquarium ever suffered from removal of bioballs too much or too fast, as there are countless surfaces in the aquarium upon which bacteria can grow. Fast forward twenty years and why are we still talking about surface area of live rock in our aquariums?

    Nearly all reef aquarists are guilty of using way more than too much live rock, sometimes cramming rock in unnecessary places in the tank, overflows and sumps. But let us ask you, have you ever seen or heard of a reef tank with a real ammonia problem? Seriously though, we’ve never walked up to a reef tank and seen animals with symptoms of ammonia or nitrite burn. The case in point is that discussing live rock in terms of its surface area for bacteria is a complete waste of time.

    [​IMG]Want proof? Bulk Reef Supply’s own measurements show what we’ve known for decades, that a single slab of a specially designed biomedia has somewhere around ten times the surface area of any rock we could possibly get. So how about we just put a nice slab of high surface area media in our sumps and say we forget about the surface area of live rock altogether?

    Well we have a totally different take on live rock surface area and it’s the inverse of what is conventionally espoused. We feel more comfortable and in fact prefer dense rocks with as little surface area or porosity as possible in our own reef tanks. The reason is that all that “internal pore network” is just as good at trapping waste and nutrients as it is at housing bacteria. Except that once the pores are packed with detritus and mulm the porosity that was supposed to be our ally in housing beneficial bacteria is now our enemy in being a sink-then-source for nutrients in our water.

    We toed the porosity-party-line for over a decade until we set up a beautiful 180 gallon reef tank with a whole lot of that awesome and expensive Pukani rock about 8 years ago. At first the Pukani rock looked amazing, it s gnarly surface was great for placing corals, it quickly grew lots of coralline algae and everyone said the tank looked amazing. Here is a video of it in its heyday.

    However after about 12 months the tank really started to shift in character – there was a ton of detritus that had accumulated in all those pores of the beautiful Pukani rock and all the flow and siphoning and water changes in the world could do nothing to stop the release of nutrients that the Pukani rock had built up over a year. Eventually the tank went downhill beyond redemption and we vowed to reexamine out approach to live rock in a reef tank and what porosity really does for the reef aquarium environment.

    When you walk up to a great or terrible reef tank, there are a lot of criticisms and praise that can be put on an aquarium system. If the water is yellow you can suggest more frequent carbon use, if detritus is building up you can offer some tips on improving water flow, so on and so forth. However, not once ever in the history of reeferdom has anyone ever praised or criticised a reef tank for having too little or so much biological surface area – just hasn’t happened.

    The real take away message is to stop getting caught up on the inconsequential details of how hypothetical things are supposed to work, widen your view and try to look at the big picture. In the case of live rock and porosity, just buy a slab of stupidly expensive ceramic biomedia, stick it in your sump, and use as little live rock as you need to hold up your corals or to build the aquascape that you really want – and reach for the less porous rock every chance you get. Tonga Branch for the win!
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  3. RiaanP

    RiaanP Moderator

    Posts: 22,998
    11 Aug 2008
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    long discussion, that lost me...

    Tell me why would the ceramic biomedia not block up as well, like the liverock mentioned?
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