# Reply To: 88 cu ft Tank and the amount of fills I should get with my Crown

Forums › Air Tanks, Pumps, Compressors, & Filters › 88 cu ft Tank and the amount of fills I should get with my Crown › Reply To: 88 cu ft Tank and the amount of fills I should get with my Crown

In the UK it's Liters with air but the math is very simple.

So 88 CUFT= 3.1L 300 bar is 4500 PSI etc. etc.

3.1L X 300BAR=930L-140BAR X 3.1L=434 (930-434)=496L __ USEABLE AIR__ (tank full volume minus the pressure when you get it refilled)

480CC X 245BAR=117L-480CC X 145BAR=70L, 117-70=47L __ per fill__ so you should get 10.5 fills (not including losses).

The fact that you are getting more means either the dive shop is filling the bottle to over 300 or you have an incorrect gauge (probably the gun). FX gauges have been reported to be upto 50 bar out on some occasions, 10-20 is probably much more common.

Hope that makes at least some sense!

In the UK it's Liters with air but the math is very simple.

So 88 CUFT= 3.1L 300 bar is 4500 PSI etc. etc.

3.1L X 300BAR=930L-140BAR X 3.1L=434 (930-434)=496L __ USEABLE AIR__ (tank full volume minus the pressure when you get it refilled)

480CC X 245BAR=117L-480CC X 145BAR=70L, 117-70=47L __ per fill__ so you should get 10.5 fills (not including losses).

The fact that you are getting more means either the dive shop is filling the bottle to over 300 or you have an incorrect gauge (probably the gun). FX gauges have been reported to be upto 50 bar out on some occasions, 10-20 is probably much more common.

Hope that makes at least some sense!