Cartridge / arm combination.How do you know?

I am suspecting my arm may be too light.My setup is a Pro-ject 2.9 wood with a carbonfiber arm and a AT-150mlx.I have played with and adjusted most everything numerous times.Sounds good but my Kyocera with an AT-14sa seem to better it.Would you think the original metal arm may be better suited or do you have some economical suggestions?

The carbon fiber arms were generally aimed at a generation of cartridges that are extinct, ones with compliance of 40 or 50. But yours may be of newer design. Try to find out the mass of the arm and compare it with the compliance of the cartridge. There are formulas, which I don't have off the top of my head, to determine compatibility. If the metal arm has more mass it would be worth trying. For a new arm Rega is the almost universal recommendation in the under $800 range.

It is also possible to add mass to a tonearm. Some cartridges use to come with a lead weight to add mass. You could try adding some Blutak or similar substance to the headshell in moderation, look at sites like vinyl engine for advice on this.

Thanks for the info
I've added a nickle to the headshell and rebalanced.Think I hear an improvement but not sure yet.
If I come to the conclusion that this is an improvement I will reinstall the factory arm.