The CERC SATA 1.5/6CH controller you are using is the only SATA option officially supported on the 1800.  You could try the PERC 5 or 6 - they are x8 PCIe cards that support SAS or SATA drives up to 2TB, and given their age and popularity, they should not be hard to find - or expensive.  If you need larger than 2TB, the PERC H700 is the first controller to support drives larger than 2TB, but again, it is not supported and may or may not work in an 1800.  You could get a non-Dell controller, but again, there is no guarantee they will work either.
Server currently has a CERC SATA 6-Channel RAID Controller which doesn't support drives larger than 1 TB.  Anyone have a suggestion for a reliable card that supports large drives and has standard features?  I'm new to hardware RAID and servers so don't know what features are good to have. Server will be used for data storage and backup and possibly as a home media server.  I'm running Amahi Home Server on Ubuntu which has a DHCP, DNS, and VPN server also. I hope to keep the cost of the card under a couple of hundred dollars but will spend more if shown why.  For my American friends, the US and Canadian dollar are close to being at par with each other - and I'm close to the border so can always get something delivered there and import it myself. Thanks to all.
Suggestions for a 6 port SATA RAID card for a PowerEdge 1800?