OK, so I keep meaning to mention this.
How accurate do you believe your tank size, as quoted by your supplier, to be?
I have a little Brodex 250 system and have always carried 10 x 25 litre poly's full of pure as reserve.
Now, when refilling the 250 litre tank it usually takes seven poly's, thus 175 litres. I do overfill the poly's, but not by that much. Refilling the poly's is the same, seven to empty (from ballcock full).
I reckon at a push it holds little over 200 litres, a bit of a difference from that quoted.
Anyone have a tank that actually holds what is claimed?
Maybe not a lot of people know, unless you decant or refill from a measured source, how would you?
Interested to hear though