dry rock conversion to live rock

does 20lb of dry rock will become 40lb of live rock when cycled?(becomes live) on marcos web site quote "Expect this rock to gain on average 50% in water weight". if i need a total of 150lb i need to buy 75lb of dry rock?

 

buying from marco, I would say that for a 150 gallon tank I could try 75 lbs of rock and see if that works. You can always add. Or you can give him a call and find out what other people have done. they are good people there.

 

Interesting....never considered that. I would just fill a third of the tank up withf LR (or dry rock) and call it good. That should do you just fine.

 

I also like the third of the tank volume rule, it's more accurate than just pounds as this post shows. The rock will hold some water, so 20lbs may weigh more, but be the same volume. I would add rock until your like the way it looks.

 

i would just buy the small amout of live rock and add the base rock to fill the gaps

quote "Expect this rock to gain on average 50% in water weight". <-- sounds dodgy to me all this is telling u is that the rock is pourus as all live rock should be from any lfs

id go with what pharmrjohn and guitar man have done

 

not dodgy in any way, shape or form. The rock comes dry so you aren't paying for water weight. 75 lbs of marcorocks is alot of rock. I would say a 3 lb marco rock would be equivilent to 5 lbs of live rock that has been tanked. oh and the price is phenominal

 

20lbs + (50%(20))= 30lbs, not 40, FYI.

(half of 20 is ten). So to follow that, (75lbs + (50%(75)) = 112.5lbs.


Also, it becoming cycled/live is not relevant - it's it becoming submersed in water that's relevant.


It's kind of annoying to buy LR because that is so often sold by pound... which means you are paying for water... at least 25% of the weight is water weight. Where as you still pay by pound for dry... wihtout the water weight...


So when people recommend 1 lb/gallon or 2 lb/gallon... do they mean dry or wet weight? I never was clear on that. The more the merrier though.

 

why is the statement (expect it to gain 50% weight) even relevant... why say it at all? Seems like a rather pointless point.


Unless... they're selling it as what it would weigh wet... if it were wet. But selling it as dry... that would be dodgy... Kind of like they're trying to justify upping the weight on the order form... I have no idea if they do that or not... but it's the only reason I can think of for even pointing it out...

I can only assume folks weight it when they get it and confirm the dry weight is what they ordered...

I haven't ordered rocks before... but if I were going to, and I noticed that seemingly pointless comment, I would assume something dodgy was up too. Too many vendors available to even worry me about confirming my suspicion.

 

I would disagree that 25% of the rocks weight is water... I have weighed many a ton of rock and would seriously doubt any of the pieces had that much water weight to them, if that were the case my scale would be awfully flooded!!

Thing I do not like about # per gallon is that rock is different densities from locale to locale.. I can tell you that Fiji LR is more dense than that of Pohnpei, Bali isn't all that dense and Marshall island rock can go both ways.

So I have a softball sized Bali rock that weighs 3#, but a softball sized Fiji rock that weighs 6#, how much # would it take to fill the tank?