Water Softeners and Air Filtration Systems - Culligan RO Unit Need Replacement Filters

I have a Culligan Mark 100 softner and a Culligan AC-30 reverse osmosis unit. New in 1998 I have always put in original filters from culligan. This time I tried some filters off the net and I have less regeneration with new filters than if I put back the old ones. the filters even look cheap. I did not replace the membrane. I got 6 years out of the first membrane, and we use this alot. This time the membrane was replaced may of 2005. Does anyone know who makes culligan filters or do they make them themselves. It is $80 for the pre, post carbon and post inline filter. What I got off the net was $35. And they say that they should be replaced every 6 months. Which the culligan say to replace yearly. They dont charge any service fees to put them in (which does only take 5 minutes) so you know they make a killing off the filters. I'm looking for some good replacement filters and if I cant find anything good I guess i will just stick with culligan.
Thanks,
Bill

If Culligan is only spending 5 minutes on the filter service, then they are making a killing off of you. There are 12 steps in servicing the AC30, including sanitizing the system - you can look at those steps by reviewing your owner's manual. If you have soft water feeding the RO system, then yearly service is standard. If not, every 4-6 months may be necessary for high quality drinking water, depending on your incoming water quality.

Good luck out there.