Feeling ripped off

AdamG280 · Jul 9, 2023

So, i noticed my 37 gallon tank only fits about 30 gallons. Why don’t they just call it a 30 gallon tank? Anybody have thoughts on this?

musel101 · Jul 9, 2023

AdamG280 said:
So, i noticed my 37 gallon tank only fits about 30 gallons. Why don’t they just call it a 30 gallon tank? Anybody have thoughts on this?

Can I see a picture of the tank? what brand is it? where did you get it?

Sleeping Giant · Jul 9, 2023

what are the measurements

zoomonster · Jul 9, 2023

Well, a few things to consider. I recently picked up a used 32g and its not possible to get the water level higher than 2" from the top and the internal overflow takes up space and not totally filled with water. Of course if you have added things like rock & sand that takes up volume too. When they state volume it's about LxWxH. Plug your measurements into a volume calculator and it is probably 37g.

Rmckoy · Jul 9, 2023

zoomonster said:
Well, a few things to consider. I recently picked up a used 32g and its not possible to get the water level higher than 2" from the top and the internal overflow takes up space and not totally filled with water. Of course if you have added things like rock & sand that takes up volume too. When they state volume it's about LxWxH. Plug your measurements into a volume calculator and it is probably 37g.

LxWxH and divide by 231

rtparty · Jul 9, 2023

Wait until you find out about the 40B…

Kellie in CA · Jul 9, 2023

It’s always been this way. I kept track when I filled my 40g, and it was only like 28g. This was before rock & sand.

Rmckoy · Jul 9, 2023

Multiply length width and height that will give you cubic inches .
And to convert to gallons divide by 231

Rmckoy · Jul 9, 2023

and when calculating volume of running tank for dosing . This is a little off . But I have always went with the tank size .
Ignored the sump or skimmer volume and assumed it would be close to the same displacement as the rocks , sand , fish etc.

Luckily for me it’s always been very close

zoomonster · Jul 9, 2023

And of course, the volume calculation includes the thickness of the glass which further reduces volume.
I also have a 200g with a 32g sump. Between all the rock and sand and half full sump, I have no clue what the actual water volume is.

Rmckoy · Jul 9, 2023

When measuring a tanks volume …
Measure the inside .

Manufacturers and lfs selling them measure from the outside which could be a bit shady …

Peace River · Jul 9, 2023

No really it’s 120 gallons!!!

Seriously though, I understand the frustration and have found it important to do my own calculations (including factoring in the sump volume and factoring out the space for rocks, sand, etc.) to make sure that I am medicating the tank correctly.

jaayy · Jul 9, 2023

Mine also like this

AdamG280 · Jul 9, 2023

musel101 said:
Can I see a picture of the tank? what brand is it? where did you get it?

Top fin. The measurements adhere to the standard 37 gallon, 30” x 12” x 22”, but between substrate and the fact that I’m not filling it to the absolute top, I’m not using 37 gallons. Still, I think it should fit at least 34. I only got 29 in there.

AdamG280 · Jul 9, 2023

Peace River said:
No really it’s 120 gallons!!!

Seriously though, I understand the frustration and have found it important to do my own calculations (including factoring in the sump volume and factoring out the space for rocks, sand, etc.) to make sure that I am medicating the tank correctly.

Exactly why I measured. Have to know the exact amount to dose the tank with bacteria or balance ph, etc.