i have an older (1994 )Sundance Calypso spa that's giving me some problems....on initial start up the temp works fine...102-104. after a couple of cycles (over night) the temp falls to about 96 even though temp is set to high. if the power is shut down and turned back on the temp then goes back to 102-104. i replace the high limit switch, had the temp sensor and temp control tested ..good...any help would be great thanks...rick