Water displacement??

[terrence]

Hey folks....although I've been reading a couple of books I purchased....I can't find mention on how to calculate water displacement.
If I have a 75gal. tank....with about 50lbs of crushed coral and a corner with 25lbs of live sand....and...6 pieces of decorative lace rocks probably weighing another 60lbs.......
HOW MUCH WATER DO I REALLY HAVE IN MY TANK???????
I guessing around 60gals....so I do a "4 bucket" water change equalling about 16 gals....is this about 25%????
I do this every 5 or 6 days 'cause I'm a tad overstocked....and I'm keeping my readings in the right area. Thanks for your input....T

 

[slick]

Your doing a 25% water change every 5-6 days? If you overstocked that bad you should get rid of some of your fish. No need to get so technical on the exact % of water to change. Just change 20g of water to be close to your 25%. When you add chemicals to your system just trim the dose back a little. But if you run a sump then your water capacity will still be different.

 

[terrence]

My tank is a double hooded "Eclipse"....I don't run anything else, but I'm considering a skimmer....just have to figure out where to put it.
Although I've read alot on this Board about water quality, etc. I set my tank up with tap water and just added "NovAqua" as directed.
I knew patience was the key.......so I cycled with 8 Damsels and only lost two over 10 weeks. I then added one fish every two weeks.....unfortunately......I didn't stop when I should have. I'm taking back 2 of the 3 largest fish. My # Dot Damsel is as large as my Yellow Tang....about 3 1/2 inches....and getting a little 'nasty'.....I'm also remove my Valenti Puffer....it never grew past 3 inches (I've had it 5 months)....but this should allow me to start a small cleanup crew.

 

[slick]

You need more bio filtration thats why your water quality is not good. Well that and being overstocked. You should add some other type of filtration.