Most likely I'm just losing a lot in fees like people have mentioned. I presume there's no way around this, i.e. there are no mixers that charge a 0% fee? And it's risky not using a mixer?
The mixer in my signature doesn't charge a fee (all amounts are rounded down to whole mBTC though), and your transaction is under the minimum to withdraw.
I don't really see a reason to mix $25. Are you really trying to hide your trail, or is it just some sort of habit?