Electrical Help for Stir Plate

Hello all, just got done a few days ago with my DIY PC fan stir plate. I have it working, but it seems a little underwhelming power wise and I need some advise on the potentiometer and rocker switched I used.

I used a 12v pc fan, a 9v DC outlet which I have read work and feel confident about. However, I purchased a 10k ohm/0.5 watt potentiometer and a rocker switch that is rated for 16A, 125 VAC. I have read the recommended specs are 25k Ohm 3 watt potentiometer, and 12V, 30 Amp rocker.

Like I said, it works somewhat well, and I get a vortex that goes maybe 2-3 inches downward, but I would like to know if by switching 1 or both of the parts I could get a higher speed stir plate.

I am sure this is a painfully stupid question, and will get many bad comments, but I am a geologist, not an electrician.

Thanks for any help!

I didn't read the whole post. I saw you're lacking power. Check your power supply. That could be the problem.

EDIT: I'm assuming your outlet is the supply. Anyhow your vortex should be fine. You don't need it touching bottom.

the low wattage rating on the potentiometer would give me some concern, but if it works it works. But if it suddenly fails, that would be the component i check first.

Thanks for the replies guys, anyone else have an opinion?