20 or keep my 15

So doing measurements to figure out what my tank size is i discovered it is a 15 gallon, much to my dissapointment. Should i replace it with a 20H gallon which is the same dimensions just taller. If so how do i do this without making the tank cycle again?

i think replacing the tank is pretty much to personal opinion, but taking the greater volume into account [dilution factor], its pretty wise to use the largest tank you can.

What kind of filtration device you using man?? actually many people make this mistake of thinking the tank have to be cycled, infact, its the filteration system itself have to be cycled.

If you planned to changed to a 20Gal tank and you're using a external filteration sysetm, simply just switch it over [monitor water parameter in case]. you can use the gravel/bedding in the 15Gal tank over to the 20gal tank too. gravel acts pretty much a good biological filteration.

Oh ok then. I am jsut using a HOB and am going to get better filtration designed for saltwater soon. I will be upgrading i just want to make the change without wasting salt.