You've come to the right place for refilling.
If you kept the original Canon cartridges those are perfect for refilling.
On the stock cartridges, the PGI-5 comes with pigment ink. The CLI-8 all come with dye ink. Quite often in the aftermarket, you will find PGI-5 compatibles with pigment ink. The primary reason for this is cost. Pigment ink is costlier. If you are not printing high volumes you will find that pigment ink is archival, i.e. does not fade, is water resistant, and allows sharper printing on plain paper than dye ink. Dye ink is normally preferred for pictures because it allows higher vibrancy and more vivid colors on plain paper as well as allowing photo paper to retain its high gloss. The MP830 will automatically use pigment ink when printing text and use the dye inks when pictures are included in the printing on plain paper.
A resetter is recommended given its relatively low cost and it allows the chip system on the printer to function normally. The benefit of the chip system is that it prevents you from inserting the incorrect color in a given slot, it allows you a visual approximation of how much ink is remaining and it also aids in protecting the printhead by issuing a warning about low ink conditions which is the ideal point to refill and reset the chip at the same time.
if you've been purchasing cartridges and kep the empty ones, the ideal situation is to keep a spare set on hand and whenever you need to change any one cartridge, you can change the complete set. This is a luxury you cannot afford to do with new cartridges each time but with refills, it costs nothing extra to do this. You start off each time with completely full cartridges and have a long period of printing without having to attend to any one color. The other benefit is that it actually prolongs the life of the ink absorber pad.
The MP830 is one of the last printers that Canon manufactured that weighed a lot. It has quality parts inside and the newer printer while having more features especially on the wireless end, are not made as sturdy and have smaller cartridges than the 830.