string swap question

Sorry if this has been covered before.

Can I use the #3 string (c on my tenor) as a low g string on the same insturment? Or is a low g string a completely diffierent animal. I am setting here at home, have a second set of strings, it ios too hot to go out side, even if the copper nails had killed the acachias, which they haven't. If the answer is I need to get a low g set, Then I will. I was just trying to do something today.

Start by tuning your C string down to a low G and see how the tension feels to you when you fret/pluck various notes.
If that feels okay, tune it back to middle C and swap out string four. If it doesn't feel okay to you, you'll need to order a Low-G string.

That's pretty much it. In general, you will find it too floppy tuned down 5 semi tones, but if works for you, go for it.

Note that you can buy/order single low G strings as well. I see Uke Republic sells a single Living Water. I know I've seen Fremont other places.