the name says it all, no secrete message, High range ph. the normal test has a cap limit so u hav this second test to test above that limit. i use the high range cause my water, without co2 or anything, stays at about 8.2
I tried the regular PH test and it came back dark blue, fast. So I tried the High Range and discovered my PH is 8.0. So if I was you I'd try the regular one and if it comes back dark blue then retest with the high range.