phono stage volume

I have a Halfer DH110 preamp and a Grado X+ cartridge. The volume is much lower than when I am using the CD or Tuner inputs. Does anyone have a suggestion as to fixing this besides buying a new preamp or just turning up the volume?
Buy a new cartridge. It sounds like you are using a cartridge which is too low output for your preamp. Was the cartridge bought new? If so, I would hope your dealer asked you what preamp you are using.

If you do have a preamp for moving magnet cartridges, you will have to get a moving magnet cartridge, or a high output moving coil cartridge. I know the grado high output moving coil cartridges are fine with a moving magnet phono stage.
more likely your preamp has just jacks for external phono preamp.
a phono step up transformer might do the trick. These are typically used when driving a MM phono stage with a lower-output MC cartridge. Or a phono pre preamp will also accomplish the desired level shift, & possibly allow you to experiment with various loading & gain settings.
Assuming the Hafler already has a phono stage, just turn up the volume. What you describe is not uncommon.
Phono preamps can require turning up the volume (over other sources). You might try making certain that the interconnects and other cables are tidy and "separated from one another" as much as possible in order to reduce the system's noise level and then see how the phono sounds @ higher volume levels. If it sound good, then don't worry about turning the dial a bit more. It is important to keep the phono cables away from power cords and speaker cable and if they do have to cross one another (can't see why they would though) then have them cross @ a right angle. I am assuming though that the G+ is a MM cartridge with fairly strong output. If it is a low output MC cartridge than, yes, you will need a step up device. sells a Mcintosh stepup device for 300 or so - it is very versatile and will give you what you need to increase gain with variable load capability.
Cford- As others have noted, just turn up the volume. The volume pot in the Hafler is rather inexpensive, so the higher the volume control position, the less it's in the signal path. I wouldn't recommend a stepup transformer or pre-preamp with your cartridge. If you enjoy the sound and the noise floor is acceptable, then don't worry about the volume control position. Enjoy the music!
Grado cartridges are not moving coil nor moving magnet; they're a hybrid design known as moving iron, basically a variable reluctance generator design. Some of their models are available with different-level output options, low, medium, high. Don't know what your X+ is set up for; give them a call to find out. You might be able to get a different model that's more suitable to fit your existing equipment.
I don't think the problem is the cartridge. I put in my old Audio Techica cartridge and its level is about the same. I think its the 34dB gain of the phono input to the Halfer. Any way to increase its gain?
Just turn it up. Unless you're past 1 o'clock on the volume, I wouldn't even begin to worry about it. On CD, I typically run at about 9-10 o'clock; with vinyl it's always between 11 & 12, sometimes more.
The advice above is correct, either a high output MM cartridge, a separate phono stage with a lot of gain, or turn up the volume. Many volume pots actually sound better at the 12-2 o'clock position. Of course, then you've got to be careful when switching sources...
32dB is basically nothing in terms of voltage amplification. You need a cartridge with at least 6..7mv output voltage.