Did a LFS pull a fast one?

[sango]

I bought a 90 gal tank from them, but when I put water in it it only took 75 gallons of water. I have the pre drilled tank but i know that does not take 15 gals of water away.. Is this normal??

 

[nguyen27]

Well, does mean that you don't have any decoration or gravel/sands in your tank? Just an empty tank and only hold 75Gals?

 

[youronlysin]

Good question. Petsmart sells a tank they list and advertise as an 18T. Its measurements are 10x20x18. That tank cant possibly hold more than 15 gallons, yet when I asked about it they tried to argue with me that its an 18 gallon tank...the tag on the shelf must be right, right?

What are the measurements of your tank. Lets try to figure out what its capacity is, then you can discuss with the retailer if need be.

 

[sango]

Sorry about that I forgot to tell ya that I have about 40lbs LR and about 3 inchs of sand.. The tank is 48 long 25 tall and 18 wide. TIA

 

[first-timer89]

the calculater on this web site says that that is a 93 gallon tank. :?

 

[grimlock3000]

If you are going to measure how much water a tank hold, you need to do it BEFORE you stick things in the tank and also account for the overflows which can take up a few gallons of water.

Petsmart sells a tank they list and advertise as an 18T. Its measurements are 10x20x18.

Yeah that is a 15H tank, I have one. Just look at the tank carton, it should say 15 gallons right on it...

 

[SquishyFish]

The overflows only take up that much water if you dont put in the pvc drains. With those, you can raise the water level almost up to to the level of the main tank. This will also go along way in reducing the waterfall effect.

 

[captivereefs]

measure the outside dimensions and multiply L x W x H and divide by 231. That will give you tank volume.

 

[steve r]

all that sand and rock will displace water. also like was mentioned you are loosing some volume to the overflow unless you put in the stand pipe. other wise you can subtract the vloume of you over lfow as well. measure it and use the tank calculator to get the volum eof your over flow our use darins formula.

try this as well. take a picture for juice / or kool aid. fill it with water to the top. then put your fist in it. it will overflow. just a simple example of displacement. i have "displaced" some water out of my tank before also by adding rock after it was full


long story short...you didnt get ripped off

steve r

 

[fishfreek]

the calculater on this web site says that that is a 93 gallon tank. :?

Then it indeed is a 90 gal tank. BTW you need to measure the inside dimentions vs the outside dimentions. A few gal + or - isnt a big deal. 75 gal tanks are usually have the same foot print of a 90 but are just shorter.

 

[XXFirefighter]

The stuff inside take up gallons...

 

[JG]

40 pounds of live rock ---- let's say the density is about three to four times that of water

then ...

40 pounds of rock should take up around 12 to 15 gallons of volume

This is only a rough estimate since the three inches of sand probably occupies 2 gallons of volume.

So - no - I don't think that you got ripped off.

JG

 

[sango]

Hey guys! Thanks for all the info