Another awesome guide. Thank you so much for putting this together. The "Actual Accuracy" portions are especially useful since that info can only be obtained with extremely accurate, expensive equipment. That light meter is looking very tempting. Do you happen to know if there is a max threshold that will damage the meter? for example would testing sunlight in various spots damage the meter because of high light intensity?

Thanks for writing this up! I've been debating getting some equipment, but wincing at the prices of some of the gear. Seeing some cheap options that perform reasonably well is great.

Nicholas - The meter can measure up to 200,000 Lux, which is a lot. No worries about measuring sunlight. The only annoying thing about this meter is there are not many digits on the display so they have a x10, x100, etc. multiplier for the reading. For $130 USD less than a commercial/industrial handheld meter, I'd say it's worth the decrease in usability.

Ensuring all tools are calibrated or verified before use is an important step in any kind of work. But at least if you buy one of these, it's unlikely to be wildly inaccurate.

Michael - No problem! It was a gamble on my part to purchase these meters and also took a while to find the right calibration/storage solutions. Happy to save others from buying complete junk. =)

Smartphone light meter apps are probably less good, but are a better judge of relative brightness than your eyes. I've had good luck with the free whitegoods light meter app for ios. Have always wanted a real light meter though.

I have the same (or same looking anyway, cheap chinese yellow) pH meter. Find the adjustment screw a bit fiddly and wish it had a digital adjustment and didn't drift as much.

Daniel - Agreed that the pH meter drifts quite a bit. Virtually all use the screw because the pots/trim is the easiest way for fine tuning the circuit. Of the above, I would say the pH meter is second-least useful to the spectrometer.

Oh man. Your gadget vetting almost made me reconsider my best-efforts-adapt-or-die philosophy, Kevin.

Of all the gadgets i've bought so far though, the spectrometer is indeed the most useless. Next is the hygrometer not because I don't need it but because calibrating them is a thoroughly mind-numbing exercise with results as reliable as earthquake predictions.

Pagan

Pagan - Maybe if the spectrometers were under $5 then it would be worth it?

For soil hygrometers, the only way to go is to have one with data logging and have it left in place. Without the consistency and logs they are pretty much useless. These very pricey meters but are also very useful. Most people could never justify the cost of a good one.

Glad that you mentioned it, I realized I have a few more tools that I missed talking about. Thermometer, air hygrometer, infrared temperature meter, and loupes. Will cover those shortly.

I only meant to measure ambient humidity because I humidify my office in winter. So certain wintering plants will thrive in it while others won't. I ended up just getting a weather station with several channels so I can see how things are under lights in the basement, outside and several other locations. And instead of trying to get absolutes, in the end I depended on data collected over T, calibrated against a sinus-based constant lol

So you can just imagine how useful your vetting will be for me. How cool is that! I truly will not be able to thank you enough.

May I contribute some ideas of other tools I've found indispensable?

Pagan

Pagan - Absolutely! Sinus-based constant sounds good to me too, haha.

I decided to get a light meter, and searched here. So many choices on Amazon

Nice! I hope this helped!

With pH sensors you are never supposed to use them with distilled water. That is why you should keep them in solution for storage, which is a little annoying. For pH calibration and testing you need to use a buffer solution which is much more accurate and clear. Small packets of dried buffer chemicals or solution can be purchased online.

Yes, though I wouldn't be surprised if almost everyone who gets a pH meter eventually sticks it in distilled water to see if the pH of their distilled water really is 7. Perhaps motivated by curiosity or suspicions of the labeling of the product.

My meter came with small amounts of calibration solutions. The instructions that came with it suggested storing the sensor in tap water, assuming the tap water has enough ions. Though, later I bought larger amounts of calibration solution plus official probe storage solution. Mine came in liquid form. I didn't think to look for packets of dried chemicals which probably cost less and store better. I realize the storage solution is basically salt water but seemed like it needed to be a very specific concentration of salt water.

Mainly, I got the pH meter for use with attempting to do plant tissue culture or starting seeds in-vitro. Having the growth media at the right pH is important. At first I tried using pH test strips but had some doubts about using those. The meter has been useful for occasionally testing soil pH, too. However, I suspect that some of the grittier things I've tested that gave me a reading of about 8.1 might actually not be that alkaline and don't have ions to be sensed by the meter.

For sure I put my first pH meter in distilled water because I didn't know better either! For a short time it doesn't significantly affect the calibration, for our general use with plants at least I found. that curiosity/suspicion for the product label, haha.

Agreed that the storage solution is just ordinary salt water, I think the concentration may be 4M? A bottle is fairly cheap and honestly the big part is me just remembering to replace it as it evaporates.

I think a digital pH meter is a huge step up from test strips. The cost difference, repeatability, and convenience of testing is so much better. Interesting note about your challenge for that alkaline reading, I haven't encountered that before.

Why is distilled water harmful to the meter? This is interesting because my pH meter actually tells me it should be immersed in distilled water, not tap water, after each use. I've done it plenty of times, always read an even 7, but I started using tap water because I decided it was too much of a pain keeping distilled on hand. Here I thought I was going to ruin the meter by being lazy, but maybe I made a good call?

This is the meter: https://vivosun.com/products/vivosun-ph-meter-digital-ph-tester-pen-for-water

The reason is that distilled water will leech out of your pH meter glass bulb and eventually it will stop working: Cole Parmer recommendations.

The other reason pH meters don't work properly with distilled water is that there are not enough ions for it to function properly: Westlab description for distilled water.

Yes, you made the good call to use tap water than distilled water. Tap water is not ideal but is better than nothing! That design is the used by a large number of companies - these cheaper sensors all come from the same factories with just slightly different housings.

Makes sense, thanks! Appreciate your work in this thread too, I've always wondered how effective these cheap meters are and this has answered a few questions for me.

I'm late to the party, but I see my dear friend is back to his nerdy self and I so love it!!! Keep well and maybe if the border opens, I might see you in October.

You bet!