How do I determine the true volume in my tank?

I am trying to decide what size powerheads and return pump to purchase for a 210g FOWLR (with the idea of adding some coral in the futrure). Based on what I have read the ext. pump should be 10x's the total volume and the turnover inside the tank should be about 30/hr. How do I determine the volume assuming the following:

The things I know so far:
1) I plan on having a 75g refugium.
2) 210lbs of live rock.
3) The suggested amount of sand.
4) 210g tank.
How do you figure/convert this into total volume?

Any suggestions for equipment?

 

Have you ever heard about the Arichemdes Law?! Archimedes - Wikipedia, the free encyclopedia
LOl...

Small hint no 1:
How many lbs of water will flush from a perfectly filled swimming pool if a 300lbs guy jumps into it ?!

Small hint no 2:
What is the density of water at 25C ?! What is the volume of 1 gal of water under this temperature conditions ?!

 

What is the temp in the pool? If its warm enough jump in and let me know.

 

Ouch!!! lol

 

LOL ... 25C

You will have approx 170gal of water after addition of LR. IF you decide to add approx. 100lbs of sand you end up with ~ 150 gal of water! 8)

 

Thanks for the advice. Did you include the 75g for the refugium in your calculation or should I add that to the number you came up to get the total system volume.

 

Please add 75 gal! It seems you would have 225gal! Wow! Impressive Good luck! Post some photos!

 

Did anyone mention pics??? lol

 

You will also need to decide whether you are comfortable returning more water per hour than you can skim. I do in my tank; in my 240-gallon system, I run about 2400 GPH through my return pump (once head pressure has been calculated), and my skimmer handles about 1800 GPH. With my CLS factored in, I am turning over water about 40+ times an hour.

 

Never heard of that one before. Who cooked that saying up??