Advice? Spilled A Little Water

Keeping the fan on it is good, I'd also put a dehumidifier as close to it as possible. Sure it would draw moisture from the tank but should help the carpet. With those steps I'd doubt mold would develope.

 

I had a skimmer freak out and dump about 20 gallons on the floor. This was in a tiled room and the carpet in the next room got wet, also had another tank next to it and water got under it. Shopvac'd what I could, mutiple fans and dehumidifiers and it was all good. No damage to tank/stands or carpet/floor walls. With your smaller amount I think you should be ok.

 

It will dry fine from the fan

 

If you have not already done so you might want to soak up the salt with rags using tap or RO water so it doesn't stain. Then a shop vac can be used to pull out as much water as possible. After that the fan should take care of it.
Having the AC on will also help as much or more than a dehumidifer.

 

Put the fan on low. People naturally think putting on high helps more, but doesn't. I learned this with my contract with ServPro when pulling water out of basements.