Here is just one of the quotes from Wetwebmedia.com
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You indicated that you disliked the use of Caulerpa in a planted sump. Can you provide specific reasons as to why you dislike the use of Caulerpa in a lighted sump for display systems (with corals/fish) -
<this is literally a several hour/many page dissertation but the short story of it all has been written about many times here in the FAQs if you care to use the google feature in a keyword search to run down the history. My apologies for not retelling the entire story but we literally get upwards of sixty or more emails daily here and brevity alas is necessary at times. The short story is that there are far more disadvantages than advantages. Yes it grows fast and yes it is a large nutrient exporter for it. However, for those same reasons is a very strong competitor with corals for the same nutrients. Furthermore, they exude noxious compounds that slow the potential growth of many corals (read: slows, not stops). They are tedious to maintain without breaching critical mass for fear of a vegetative event which is inevitable and potentially catastrophic in many systems. The list goes on. There are much better macros out there. Caulerpa is popular because it was commercially marketed, not because it is the best choice. See how many corals you can find in Caulerpa zones on wild shores (zero or nearly so... there must be a reason!)>
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Here is the link if you are interested:
http://www.wetwebmedia.com/caulerpafaq2.htm