fuel capacity

I just started my aviation journey, as I learn more I'm coming up with all kinds of questions that thankfully I've had alot f very good input from the folks on here. One question I have now is, can you extend, modify, or increase the size of the fuel tank in a Cessna Skylane/Skyhawk series for...

I have a simple question. The Arrow III has a total fuel capacity of 77 gal of fuel vs 50 on the earlier models. Is there a “visual” way to know when the tanks are at 50? Like tabs or something like that? If not, how many gallons of usable fuel do you have at “tabs” vs the 72 usable when it’s...