I recommend the liquid kits. The strips always gave me wacky readings. My tap was 6.8 and then my tank was 6.0. Got the liquid and it turned out my ph was actually 7.2.
my tank is stable at ph of 5.3 and nothing is wrong with themm just got a lots of acidic soil.
better if its little on the acidic side for most of tha plants anyway, i say dont worry about it till you see your fish starts acting up.