Good that you can test for almost ever now
pH take some tap water in a cup and let it just sit for 24-48 hours and see if there is any change and possibly will get a more true number.
Also when you rinse the tubes and think they are clean, clean them some more. Shake them again with more clean water and cap it with a finger (can use a glove if the chemicals bother your hands), and shake some more, again with fresh water to remove any leftovers. Edit: for clarification I mean using your finger on the end for cleaning only not for the testing part.
Can help to make sure you have accurate readings. Along with following the instructions well.
GH/KH is another test with additional bottles. You may be able to get the info from your water department about your tap water. Also you can get it tested often at your local fish store for from free to around $5 per test for both KH & GH/visit. But IMO if they want $5. just order it or buy a kit. (unless it is an emergency/urgently needed) You do not always often need the test but invaluable if you do. Borrow one is a possible option if you have a friend who has one.
Although most fish will be just fine in that pH, plants like it even more, around 7. Not something to need to alter chemically and NOT a big issue. DW could help lower the pH naturally, or leaf litter for any tank/ community planted, not needed with some fish. I only mention it so you can get a feel for what to do with the tank(s).
Some water will have elevated levels of these things like nitrites and ammonia in it. If you test your tap water, you can get some practice as each test is slightly different way to use it. And would at least do it to get a feel for the tap water you have so you know what you have to work with.
My water had .25 ammonia. I remember setting up my shrimp tank and having everything ready to put them in and fresh pure water from pwc and still having ammonia .25 and I was racking my brain trying to figure out what I did wrong, doing several more pwc all with the same result, and it was the tap water!!! I hadn't ever tested my tap water back then.