Hi Alex,
I have successfully imported CSV files on numerous occasions.
However, the format of the files that works for me is like this.
Note there is no header row, just 3 parameters on each row separated by a comma (lat,long,depth)
-41.299869,174.462676,188.7
-41.29995,174.462736,188.84
-41.299946,174.463017,190.6
-41.299921,174.464114,194.92
-41.29992,174.464154,194.86
-41.299969,174.465598,198.27
If your files are too big Reefmaster might not import all records.
I found a free program called CSVSplitter.exe online which allows large files to be broken into smaller parts.
Good luck.