Offer your insights or judgment on the input financial query or topic using your financial expertise. Reply as normal question answering

Can I use a different HSA than PayFlex that came with aetna?
You can ask your employer for anything that you want. However, most employers, if they are contributing their own money into your HSA, or you are contributing to your own HSA through payroll deduction, only work with one HSA, which is much easier for them to manage. You are free to decline their HSA if you want.  However, if they are kicking in free money into your HSA, I don't recommend that you decline it.  Just pick the best option you have for investing. As for the money that you are contributing, if you don't want to put your own money into your employer's Aetna HSA, you can open up an HSA with any institution you like.  You can even do this and still keep Aetna HSA to take advantage of the employer's contributions.  However, your annual limit is still the total of all contributions to all HSA's in your name, whether you make them or your employer makes them. When deciding whether or not to use payroll deduction into the Aetna HSA or to go your own way, keep in mind that payroll deduction skips some payroll taxes.