Probably too late, but if you have an established tank I would just buy base rock vs buying more live rock. Anytime you buy live rock you have the huge risk of bringing in critters and many of them will be unwated critters. Most LFS sell dry base rock either by the pound or by the box.(usually under $2.00 a pound) I’ve brought a lot of this base rock to life. Same stuff just dry, light, cheap, and free of pests.
Jon
i thought base and live are different? base being more dense and live being more porous? i know you can seed base but doesn’t have the same filtering qualities.
thanks chris
They are not the same thing, one has the “live†bacteria we want for the Nitrogen cycle and the other is dead. They can have the exact same filtering qualities because they are both made of aragonite and are both capable of hosting denitrifying bacteria. Pick up some base rock and take a look you’ll see it is just about the same thing, but dry.
i see the base rock that you’re talking about. i have also seen people use other rock such as lace rock as base thats why i was asking. i didn’t consider base and other denser rocks to be base.
chris
Sorry newsalter this is Jon, I work at Premium Aquatics… I’ve helped answer a good bit of you’re questions in the past on the phone and in the store. The youngest of the guys that works there.
IanH we are a little short on LR right now, but hope to get some more soon. Dense and porous terms are relative. All of the rocks we have if my memory serves me correct, both LR and base are very porous when you speak in terms of biological function. The way much of the rocks we have are structured(being that they were created by certain types of corals) hold a lot of water and allow water to flow through them very slowly, but in large amounts. Exactly what you want for biological function. Hard to explain exactly what I mean by all that online with out digging up some photographs and drawing diagrams or creating animations or something…. much easier if you grab me next time you see me in the store and I can explain with examples and demonstrations.
Jon
i will be in later today… thanks i thought that was you…lol
Dense and porous are relative.
Relative to the volume the rock takes up, the volume of air inside that volume, and therefore the volume of water it can hold.
If a rock is dry and it is heavier than another rock of similar volume and dry, it is more dense. Higher density means less water than can be in or flow through the rock.
The more porous (and equally porous throughout) the rock the better for filtration.
I can agree that slower moving can be better for filtration, but if it is too slow throughout the rock the water movement will much more readily flow around that rock and its internal parts wont function for filtration.
I’ll swing by sometime and we can talk about it. I do R&D on filters for life support and breathing apparatuses for a living.
The importance of rock being porous is simply to provide surface area for bacteria to colonize, it has little or nothing to do with flow. The bacteria is going to do its job simply by being in contact with the water. Flow would only matter if there was NO movement which would result in depletion of oxygen. I agree that density is relative but its not because of volume, it depends on the geological composition of the rock.
i would agree on those points. that is why we like to use more porous rock as opposed to dense rock such as granite. or ones we could dig up in out own backyard. Had some guy tell me that is what he did?? if we were just talking about bacteria growth well, as long as you had that on your tank walls and other things in your tank we would have no need for live rock. besides we like the way the rock looks .LOL
I agree 0% with flow not mattering. You’ll have to sell that one to me.
Geological composition? Density doesn’t have to do with volume?
Wikipedia: The density of a material is defined as its mass per unit volume
i was agreeing with you Ian. lol and you do need flow that is why you cure live rock with a power head and heater and lights with lots of water changes. isn’t that why we worry about turnover rate in our aquariums and put powerheads in out tanks. etc.
I didn’t want to dive into this too much, but I’ll have to try to explain what I mean by the porosity of LR effecting it’s capacity of denitrification using pictures once my camera charges.
"if we were just talking about bacteria growth well, as long as you had that on your tank walls and other things in your tank we would have no need for live rock. " Completely disagree with this statement 100%. When someone is starting an aquarium LR is pushed as one of the best things you can do to start the aquarium out right. This is not because all reefers agree that an aquarium with out live rock wouldn’t look right at all and just totally wouldn’t be the stylish look to go for out all. If you do not understand the importance of the Nitrate cycle, which is understandable you’re still new at that stuff, I would highly suggest you do a little more reading.
Well actually I agree with you’re statement, but not in the manner that you understand yet. There are many types of bacteria that live in the reefs and in our aquariums and LR gives us the ability to maintain bacteria that convert Nitrate to Nitrogen gas. This denitrifying bacteria needs an anaerobic environment to do so. The inner most areas of LR is where these reactions take place.
“Flow would only matter if there was NO movement which would result in depletion of oxygen.” I’m confused by this statement. Depletion of oxygen in the water is one of the main purposes of keeping LR in our aquariums. I suppose it depends on what you mean by “flowâ€ÂÂÂÂÂÂÂ. I suppose you could argue that aquarist most often use the term flow when referring to power heads and water movement in the aquarium as a whole(this coral needs “high flow”). If we are talking on that scale of high, medium, and low flow then inside of the rocks where denitrification most often occurs there is “no flow”. Though, water is transported slowly through the rocks(the sort of flow I was referring to earlier) or else this denitrification would be worthless to remove Nitrates from the water our fish and corals live in.
sorry guys i was just in one of those moods… lol at least this sparked some conversation.
This is where i disagree.
Higher density means less water than can be in or flow through the rock.This makes no sense. If i have two identically porous rocks with identical volumes, the only thing that density would do is make one heavier than the other. I dont have a degree in geology, but i would guess that live rock from different parts of the world would have different geological compositions which would infer differing densities. The only way that what you said would make sense is if you said the rocks had the same volume, same densities, but differing masses....this would imply that one was more porous than the other.
Here is a simple analogy. Imagine i have two cubes of identical dimensions, the both have an identical hole through them making them equally porous(defined on a macro level). They alos both have equal surface area. Now lets imagine that one is made of steel and the other is made of pvc. The will both displace the exact same amount of water, therefore equaling the same volume and the will both be equally porous. The only difference is that the steel cube will have a higher mass than the pvc cube which gives it a higher density.That is what i meant by having nothing to do with volume. Its also the part of the equation you left out, mass. Which would be defined by the geological composistion of the rock. Now if were looking at it from an atomic perspective we could say that the pvc is more porous than steel, which it would be, but i would love to see someone get the same effects from pvc as we do from live rocks. Its all about surface area.
Maybe i read it wrong, or you just werent clear. Im not sure, i have a tendency to not be clear. As far as the oxygen vs flow comment, i guess it depends on how you define flow. im with jon, i read flow as meaning turnover(i.e. powerheads, water movement) which is not necessary for the effects of live rock.
This denitrifying bacteria needs an anaerobic environment to do soJon, i do have one question. Do the bacteria need an anaerobic area, or do the bacteria create an anarobic area? I was always under the impression that its the bacteria itself that consumes oxygen creating an anerobic state, not the other way around. But i could be wrong, wouldnt be the first time. >LOL<
There are actually two main types of bacteria in our tanks… nitrobacter and nitrosomonas. One uses oxygen to convert ammonia to nitrite and eventually nitrate, and the other is an anerobic bacteria that converts nitrate to nitrogen gas. I cant remember which is which without going back and looking at my aquaculture class notes, but the one that is anerobic cant exist where there is oxygen.
There are actually two main types of bacteria in our tanks... nitrobacter and nitrosomonas. One uses oxygen to convert ammonia to nitrite and eventually nitrate, and the other is an anerobic bacteria that converts nitrate to nitrogen gas. I cant remember which is which without going back and looking at my aquaculture class notes, but the one that is anerobic cant exist where there is oxygen.
Well, that makes sense and it explains my confusion. I thought for sure that they depleted oxygetn because i know when you use any type of denitrator the water that exits the reactor is depleted of oxygen.
The physics i can handle, the chemistry ill leave to you and Jon >LOL<
I thought nitrosomonas converted ammonia to nitrites and nitrobacter converted nitrites to nitrates and pseudomonas were the anareobic denitrifiers. But it’s certainly not my area of expertise.
Either way … imho … it’s all about the surface area that the live rock provides for the aerobic bacteria … whatever it’s name is. Density and volume are nice things to yak about, but the surface area is what counts for growing more bacteria.
And likely very few of us have any anerobic bacteria - except maybe Ken and his plenums. Or if there’s a DSB somewhere in the system.
btw … are we still talking about buying and selling?
it's all about the surface area that the live rock provides for the aerobic bacteria
that was my comment almost verbatim that started this whole mess >LOL<
btw ... are we still talking about buying and selling?
It wouldnt be DRC without a good old thread hijack!
[quote=“ronert, post:17, topic:770”]
btw … are we still talking about buying and selling?[/quote]
Lol, no, not at all.
I have split the topic, but don’t have the ability to move it to General Discussion, if someone wants to move it there.