Throughout the years I give to a specific tzedaka organization. tzedaka and maaser. At times when I’m low on funds myself I borrow from that set aside money and just mark down what I owe plus a little bit. Is this allowed? Is there any reason not to especially since I add to it? Would there be anything that i shouldnt use borrowed money for? or since the tzedaka is making more money out of it this is allowed? thanks!
Yes, it is allowed even without adding any money.
All the best
Gemara Archin 6a, Y:D 259:1