Nope. Thus I do not know about pH meters.

It is my understanding that a bin will self balance right where it needs to be. This is as long as 90 pineapples, a case of oranges or pounds of pine needles are not added. Even these will eventually self balance over time.

It is my understanding that worms can live in a huge variety of pH's. Changing rapidly to "correct" is what hurts them.

I have never added any type of lime to correct pH.

I would not suggest it.

Probably if one is not running a business of vermicomposting then we hardly even need to think about pH.

In my opinion if pH is off the best thing to do to correct it is to add more cardboard.

I don't either. As you're not mixing, your PH would vary anyway depending on location. How would you treat one location that had fresh citrus lowerin the PH, while the rest of the bin is neutral. As usual, as long as they have somewhere else to move off to (bedding) while things might be suboptimal in a location, they are fine.
Some worms were hurt in the making of this video... http://www.youtube.com/watch?v=DC4CG3e618M

If you are one to save egg shells, you can always keep them for times you feed more than usual citrus. I've just fed a not so nice mix as I had some fruit go off over the holidays and I made a brick loaf while baking bread. So citrus and starch in more than usual amounts with my usual waste. So I used my crushed eggshell supply with that feeding.

But that's about all I do in regards to PH.

My nose is my pH meter, LOL. If it smells off, I'd add shredded paper product and powdered eggshells.

PeterK2, what's your process for adding bread to the bin? I started a loaf an hour ago and it has yet to rise any. I suspect that I killed the yeast with too hot of water but it has been a few months since I used the yeast at all.

Lol, the trials of bread making. I keep it and mix it in with regular feeding. Usually half at a time if it's a loaf brick. If you've never done bread before, it's another way in which those Inn systems shine. In a bin they can become a soggy mess and you can just smell the yeast, can be real horrors. In the drier Inns, it's not nearly so bad. I wouldn't be doing half loaves in bins, easy to go mush on you and anerobic.

So as in my last batch, I have my veggie and citrus feed in a bucket. I crumble (I've let it dry) half a loaf in with some older VC (to get some starter bacteria spread around) and mix it all up. With lots of bread I keep it on the drier side to try and avoid fermentation. This mix will definately warm up (more than anything else I've done) as in the other thread on heating ;). I then cover it with some VC and bedding as it will mold. Basically what I do with all starches (rice, potatoes etc.)

BTW, that's with baked bread. Never done anything raw. Might want to still bake it even if hasn't risen just to dry it out so you can crumble if nothing else. Also quantities are in relation to an almost full Worm Inn.

mr_yan, I think most of us that have been vermicomposting for a while would find using a pH meter a bit tedious. Its sort of like using a measuring cup or spoon for a recipe you have made a thousand times.

The process of feeding worms for me is fairly simple. I save gravel syphoned water from my aquariums to water plants and mix scraps for worm food. I have a number of five gallon buckets with left over garden scraps of all kinds which sit covered in my shed for the winter. As needed I will take a variety of scraps into the garage to thaw out and mix with new scraps. Add some aquarium water to this bucket and in a few days things start to mold.

At feeding time I take a scoop and stir the mix before adding a scoopful to the blender with about two cups of aquarium water. Turn on the blender for no more than a minure. add some more scraps and water and blend again. I leave this blended mix set for at least fifteen minutes before blending again. Those soaked scraps, thrice blended, form an emulsion which worms go through quickly.

I think the biggest advantage to this method is in the variety of foods which are fed, rather than one or two items, which may as suggested here be pH modifying if over fed.

Thanks guys. I thouhgt of this after the crushed egg shell thread as the shells will swing the pH with all their calcium.

Measuring cups for cooking. Unless i'm baking i don't even use them the first time.

mr_yan...another thought for you is litmus paper if you have some issues with pH. pH sampling is of little value even when having a certified soils laboratory analyze your soil samples. After 15 minutes the sample becomes unstable, especially in solution. From experience I can tell you, laboratories use their least experienced personnel to run simple tests like pH or total solids, and more often then not you are wasting your money having them perform these analysis. Litmus paper is cheap and will give you just as reliable an answer as sending your sample(s) to a lab or using an inexpensive digital pH meter.

Unfortunately, the $20 soil pH meters are pretty much garbage (at least from what I've tested).

If you regularly add crushed egg shells (calcium carbonate), the pH of the bin will be buffered at around neutral. So, you don't need to worry about it.

If you don't have enough egg shells, you can use agricultural lime which is the same CaCO3.

I grind up my eggshells in a blender, as long as I see some tiny bits of eggshell in the finished VC, I know I am adding enough.
Under usual circumstances, you can't add TOO MUCH eggshell.