My tank runs a regular pH range of 8.15 to 8.35 these days but I've kept tanks in the past with pH in the 7.9ish on the low side to 8.2ish on the high side range that did great for years. If my pinpoint monitors were reading right.. which I think they were most of the time.... 7.9 pH on the low side of my pH swing never hurt and didn't keep my tank from experiencing nice color and growth.