They can help a little bit but keep in mind that a shower filter can’t soften water, although some popular models like the Shower Envy make this claim. The water passes too quickly even if the right filter media is used. You’ll see some good results if you use one that reduces lime but the reality is that you need a water softener filter that either fits under your sink or does the whole house. A resin based water softener, like Sterling water softeners, will be extremely effective in softening your water.