Ok here's a PH pen modification I did a while back -thought I'd post it in case it helps someone out. With these cheap crappy PH pens ( I haven't tried all brands but get the sense they're all pretty fickle ) the main problem I've had is the reservoir tip only holds a tiny bit of buffer solution, and once they dry out they're never the same again. Mine is/was good for a week or maybe two in my room but after that it's dry. Now I really feel no love for this pen and I have a regular graveyard of the damn things but I sure miss it when it's gone! Always have yourself a backup like PH test drops or the paper strips. One of these days I will spring for a real combo meter, which of course I could've paid for by now with all the money I've spent on crappy pens! Lol...
Not sure why I didn't think of this fix sooner than I did. I'm sure someone has but I haven't seen it.
This one not so great picture is pretty self-explanatory or I would have taken more for you but here's what I did:
Found the best container I could around, which in my case was a baby food jar. Not the best. Ideally the container would've been a little bit shorter and smaller plus the lid screws on kind of funny but this is all I could find on hand.
Traced the reservoir outline on the lid, then marked diagonal lines from the corners of outline to the center.
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Cut along those diagonal lines. I used a small chisel and put the lid on a small piece of wood for backing and carefully hammered the chisel down on those lines to cut them. Then with pliers I bent and folded the resulting triangular flaps downwards. Then I slid the reservoir cap in. Mine fit quite tightly. Make sure the pH pen still slides in and out of the cap easily. You may have to adjust it so it's not pinching the pen and making it hard to fit.
I drilled a bunch of holes in the bottom of the cap.
Then I took the cap out, spread a bunch of five-minute epoxy on the relevant areas and slid the cap back in.
Then glued something flat and heavy on the bottom of the jar to make the whole contraption more stable. Even though it was pretty good already. What I stumbled on at the time was an old metal cutting/grinding disc.... Yeah I'm not putting much love into this but I pray it's the last pH pen I will have to suffer with. Not very elegant but you get the idea anyway if you want to make a nicer one.
I filled up the jar with pH 7 buffer solution, screwed the lid on, and I'm good to go. I think now I can safely leave this pH pen for months and I don't have to worry about tipping it over so much.
