I’ve had that exact set and my ph was well off after just a few times of use I ended up getting a essential one get in most good stockiest and reads ph bang on every time
I use a soft covered wire that doesn’t harm plants get it on Amazon and if in fabric pot just poke a hole in side then tie wire to pot and hook round stem and bend slowly can pull bit more each day
Diatomaceous earth is organic powder place this around all skirting carpet and any areas were they found it’s harmless to humans and pets leave it down and this will kill them and then u can hover it up after