TDS meters come in different ranges..some are ppm 0-1999 ppm and some come in ppt 0-10.00 ppt..what is ppt and is the range 0-10.00 suitable for aquarium use...I was just wondering as I can get a meter but it is 0-10 ppt and I never seen this form of readout before...my old conductivity meter was in microsiemens...the resolution is 0.01 ppt on the meter I am looking at...any info would be greatful.... Al ------------------------------------------------------------------------- This is the apistogramma mailing list, apisto@listbox.com. For instructions on how to subscribe or unsubscribe or get help, email apisto-request@listbox.com. Search http://www.digital.com for "Apistogramma Mailing List Archives"!