True or false assumption???

[Fly Guy]

For a larger system, assuming you have excellent water flow, would it be a correct assumption to think that you wouldnt necessarily need quite as much live rock per gallon of tank capacity??

[clockwork]

wrong IMO . It about filtration and husbandry .

Flow helps but it doesn't process waste.

[Fly Guy]

To be sure maybe i should give more information as to why im asking this question........for instance, in my 90, i run rock wall to wall and probably 130 lbs of rock. For the 225 im building im thinking of putting just 200- 225 lbs or so with an 8 way oceans motions moving water through the rock which is going to be lifted off the substrate with hardly any flow restriction beneath it. Im just wondering if under these circumstances if 300+ pounds of rock is really necessary. Im thinking not but just wanted others input. Clockwork, i appreciate the response and am curious if you feel the same way knowing a little more.

[Geoff]

i am not sure anybody really knows the answer to this. i do not think we need the amount of LR people recommend. people just like numbers to through around so the 1 to 1.5 lb thing came about.

in my rebuild i a lot less LR than it looks. it may look like there is a lot of LR in it, but my two big mounds are completely hollow.

as long as the flow in the tank is able to actually use all of the LR than you can get away with a significantly less LR than you may think.

in BB tanks it is easier to get this flow than in a SB tank. unless you use racks to keep the LR off of the SB.

G~

[Loverotties]

False,same amount!

[motorslave]

Originally Posted by Loverotties

False,same amount!

I have to disagree. I think that flow is very important. I had 90lbs in a 150 with huge flow and had perfect water. The 90 lbs wasnt then final amount but it was there for most of the tank time with water (being redesigned into an inwall) With properly designed flow and a very good skimmer i think you have much more room for using less rock. of course you need to have enough bacteria to handle the bio load but if the flow is designed properly, nothing collects on the bottom of the tank, the rock is blasted regularly youre good. My flow kept EVERYTHING in suspensiona and it all wound up in the sump. The sump was designed to keep the goo in the skimmer intake compatmenet for ample processing.
Also using porous rock will alolow for much less pounds per gallon. I just dont think its needed to dump a ton of money to fill a tank with rock if you design things properly. Smart flow, husbandry and a killer skimmer do wonders.
The new set up with the 150 will be better in the terms of flow and the skimmer has been added onto so its much more powerfull. i will be running around 100lbs of rock in a system with a total volume of 220 gallons or so. Look at Spankys tank, his is very much open water and it thrives. Simple and well thought out design is a key. Flow is the m,ost under utilized tool we have in my opinion.
How many people really take the time to "design" flow in a tank. Im not talking about adding a CLS or a bunch of power heads. Im talking about putting thought into what you need the flow to do and what it will do in a full tank.
"you need more flow" is a general statement that says nothing but add some movemenet. Make the flow work for you, it can do wonders. Buy the right rock so you can use less if you are aiming for a more open looking tank. Buy a skimmer that is far more than you think you need. If the disolved solids are removed early then that is less for the bacteria to have to process. design the sump in conjunction with the particular skimmer you have to have an extremely efficiant set up. Whay pay $800 for a skimkmer if the set up wont allow it to work to its full potential.

Just my thoughts

Robert

[motorslave]

Check out Gregg T's tank in the thread on this forum. He has little rock when you look at the "lbs per gallon" "rules". I think design is the key.

Robert

[theplatypus]

Isn't the density of the rock also a contributing factor? Dense rock has less biological filtration capacity than very porous rock. Please correct me if I'm wrong here. From what I understand TBS rock is very dense so you need more of it to achieve the same results as a more porous variety.

[motorslave]

Originally Posted by theplatypus

Isn't the density of the rock also a contributing factor? Dense rock has less biological filtration capacity than very porous rock. Please correct me if I'm wrong here. From what I understand TBS rock is very dense so you need more of it to achieve the same results as a more porous variety.

Exactly. Thats what I was getting at refering to using more porous rock. It has more surface area to house the beneficial bacteria. Tonga and marshall Islands are both porous rock. Id rather spend the money on better rock and have more open space in the tank for fish and for flow to circulate.

Robert

[clockwork]

FlyGuy- It still comes down to filtration and husbandry . But also keep in mind those unseen deaths . Having more would help at that point IMO.

My wrong comment goes towards the flow .Its more than the flow that makes it possible to use less rock but still have all the benifits you need from it.


You can use less rock no problem but your husbandry and nutrient export need to be up to par. I have a 180 and have nowhere near 360lbs of rock or even 300 I think I am close to 230lbs.

Really if you plan on having a light live load(fish ) then you can get by with less rock no problem. But if you want tons of fish you would want that extra rock and highly agressive nutrient export to keep things in check .

Here is a pic of my tank . Do you think thats alot of rock ?


Lets say compared to this. 90g of mine . Think about it this tank is half the volum of the 180

[clockwork]

I also agree dense rock sucks for biological filtration and it is best to find stuff that is porus and has openings.

I dislike figi alot for that fact.

[Fly Guy]

thanks clodkwork...to be honest........unseen deaths are kind of a non-issue for me. I will have a very light fishload (but they will be predatorial)and the way i lift my rock and aquascape.....there is 100% free flow underneath the reef. Right now in my display 80 im guessing ive got 120 pounds of rock.........but i think thats MORE than enough as it is all large porous rock stacked with space as well as 100% free flow underneath. I honestly couldnt fit any more rock in there if i tried. Thats wall to wall and within a couple inches of the sky in some places. But i do not own any dense rock either. I sell it along with my xenia and gsp's whenever i end up with some. : )
I just asked the original question int he first place becasue i want a little more open water in the big tank and just wanted to be sure. I think im comfortable with my original plans...again...just wanted some confirmation.

Thanks for everybodys input

Ok....100% free flow underneath is exxagerating......lets say 96%.

[salttanker]

IMO, filtration is very important. I think the number most shoot for is 10x the tank volume per hour. Rock serves an important biological purpose, and some will say to get 2lbs. per gallon. I have a 120g with 180lbs. rock. It has served it's purpose over the last 2 years. Better to have some then none imo.

Mike

[motorslave]

i agree, filtration is very important. It is also important to make the filtration as efficiant as possible. That comes by using flow to keep detritus suspended so it will get to the skimmer of whatever method you use. The more your system can accomplish this the better. Rock is extremely important but a good flow design will allow for more possabilities when it comes to rock if you are shooting for a more open look. Having tons of rock without good flow can be a detriment also. Without good flow alot of detritus can settle into the rock and over time it will become saturated.
I think that as long as its well thought out, we can make any set up work when it comes to the amount of rock (with in reason!) And of course as said, bio-load is a big factor along with husbandry habits!

Robert