It isn't an issue of needing something better than the blue biomedia. It is a very good form of biomedia. The issue is that you do not want ANY form of biomedia in a reef. The unit itself is a great piece of equipment for a Fish Only aquarium. I have used it many times and actually own the larger double skimmer unit, but I would never use it on a reef. I wouldn't even think about it.
You do have a big advantage going for you. The skimmer itself is adequate for a 29 gallon reef. No problem in my opinion. So, you can remove the biomedia and just run the skimmer as is. I would personally replace the biomedia with some small pieces of live rock, just to help eliminate bubbles from entering the aquarium display.
I understand you trust your LFS guy. I am certain he intends well. However, I do not think you were clear with him that this is going to be a reef display. Or perhaps he has a lot of fish only experience, but is a little less experienced with how to properly design a reef aquarium. This is a HUGE issue. The negatives of biomedia in a reef will significantly hinder your chances for long term success.
The basics of your display should include a 4'' DSB, live rock, and a protein skimmer. The use of activated carbon is debatable depending on who you talk to, and the use of mechanical filtration should be completely avoided. These basic points are not up for question in "the hobby" as it exists today. All of the experts basically agree on these simple facts. A quick trip to your local library will verify this for you, provided you read anything dated after 1995. Julian Sprung and Charles Delbeck's 3 volume set would be a fabulous investment.
