2 Pack pH Test Strips, 160 Strips pH.1-14 Universal pH Test Paper Litmus Test Paper Soap Making Testing Strips for Water Wine Saliva Urine Soil Testing Pet Food and Diet pH Monitoring (Sealed Pack)

I have a more expensive one now but used to use cheap ones from amazon and they worked fine for as long as I remembered to not submerge them in water. The cheap one by no means lab grade but you just need to know if it's 4,5, or higher. More options but same issue of breaking after a season if I didnt treat it right. Litmus paper the cheapest but you have to store it correctly. To actually use them you take bottled water (unless you have low ppm tap water) and slowly saturate your soil sample (lets say about a pound of soil, half from 3 inches deep and half from 6 inches). What you need to acheive is the full sample to be wet without there being standing water in the cup, so you can add a little water at a time, maybe even walking away and coming back later between applications if your soil is slow to absorb the water. The moment the sample can hold no more water (ie water starts pooling at the bottom), pour out the excess at the bottom. Then let the soil sit for 5 minutes. Finally, get another container, grab a handfull of your soil and squeeze the water out of it like a wet sponge into the new container. This liquid is what you measure. That procedure might aound complicated but really all your doing is getting the soil as wet as it would be after a watering then squeezing that liquid out to be tested. Doing this gives you a low-end estimate of the acidity as when soil is less-than-saturated the acidity will be concentrated. However, this is a good ballpark estimate and doesnt require a laboratory. For blueberries, I like to shoot for pH 4.7.

hmm that's oddly low again... i'd 2nd mossking69's idea ethylene dosing. Try a couple segments in a paper bag with bananas for a few days i think your PH strips are working OK, i have some of the same from lab rat supplies. if you want the paper ones though they're pretty common wherever you get them like these:https://www.amazon.com/dp/B0C72RTK1C skinning bridges like those might be easier than other varieties, i would.

I gave up on ph meters they either break easy or calibrate incorrectly, I just use TDS/EC to the ppms. I use ph strips or drops https://a.co/d/0dpJSG0t https://a.co/d/08fK3XA6 My ph has been dialed in using low amount of nutrients and cal-mag complete to drop the ph 5.8-6.2 prepping my water because i grow coco and If i need to increase the ph i just add a pinch of baking soda. I vegged some plants for 7 weeks and then flipped to flower last week and not had one yellow leaf or tip so far.