I know the difference but not the consequences so . . . I have an old gadget, a digibox of sorts that supposedly monitors the water flowing into the fish pond and helps keep it clear. The transformer feeding it has packed up but has, or had, an 18vDC/1000ma output. I do have one similar that used to feed the rockery lights but that has an 18v AC output. Will it blow up my digibox if I use it or is it a visit to ebay?