Live Rock / Dry Rock Ratio

[gridley]

Here is my second question for the day . . .

As my wife and I are moving closer to getting water in our DT, we need some advice on rock. We have decided, partiially because of cost, to begin with a mixture of dry rock and live rock. Our DT is 90G and our sump, when operating will have a capacity of 23G. We are planning on running with a skimmer and carbon and GFO reactors. We have purchased 50 lbs of dry Marko rock. What advice do you have on how much live rock we should add to that?

Again, thanks in advance.

[afsportsguy000]

70-80lbs of Dry 10-20lbs live.

after about 2-3 months it will be fully ready to go

[sponger0]

Or you can do whatever ratio you want now, get all the rock your ognna use, stick it in a plastic bin with saltwater and a powerhead and let it sit until your ready to fill your DT with water.

[pugbreath13]

I would go with all dry rock to start with. The major benefit other than cost with using dry rock is you do not introduce any unwanted critters/weeds to your tank. That one piece of liverock could be covered with bryopsis spores and be filled with mantis shrimp. You will get all the diversity you need from crab/snail shells and coral frags.

[sponger0]

I would go with all dry rock to start with. The major benefit other than cost with using dry rock is you do not introduce any unwanted critters/weeds to your tank. That one piece of liverock could be covered with bryopsis spores and be filled with mantis shrimp. You will get all the diversity you need from crab/snail shells and coral frags.

On the other hand dry rock can leach lots of phosphates into your tank...causing bryopsis. Also it has been recorded that dry rock produced hitchhikers, including bryopsis on rocks that had been dried out, bleached and boiled.

Just make your own decision and handle what comes your way, whether it be bryopisis, phosphates, mantis shrimp or an octopus.

[gridley]

So, if I use dry rock only, how does the bacteria cycle get started?

[sponger0]

Ghost feeding is the most popular method. Using some store bought shrimp or regular fish food.

[Empty Bottles]

I'm in the exact same boat as gridley. 90g I'm fixing to start getting rock for. The cycle will start with just the introduction of ammonia or will we need to add something that has the bacteria in it that breaks down the nitrogen?

[gridley]

The replies have been very informative and helpful. The dry rock only route sounds interesting. If we go this route and ghost feed, is there any thoughts on whether this takes longer for the tank to cycle and be ready for the first fish, as compared to using some live rock?

[Empty Bottles]

From what I've gathered the less LR you have the longer it's going to take to cycle. I'm not sure if you can cycle with dry rock and a form of ammonia only though, I don't know where the beneficial bacteria comes from or if it will create itself.

[HaKs310]

It will create itself.

I just set up a 12g NC using only old, dried out "LR" and dry sand. You will need to introduce ammonia to get the bacterial population to the levels where you can house a fish; via ghoot feeding, regular ammonia, or a dead shrimp, Once a fish is added it will add more ammonia, thus helping the bacterial population grow once more to consume all the ammonia. So you are pretty much going through mini-cycles anytime you add an inhabitant that will input ammonia into the system. This is why it is advised to add fish one at a time, with a couple of weeks in between additions; to let the bacteria population catch up to the new ammonia amount.

Dry rock will take longer as there isn't bacteria on it as a piece of LR would. I would get about another 40lbs of LR; or 20lbs of LR and another 20lbs of dry rock.