tinytoon,thanks for that valuable information. I will put it to good use :thumbsup: I'm going to keep a fwe in the crisper for staggered grows and/or potential replacements for failed experiments.

I mentioned earlier in my thread that I wanted to eventually drill a hole into the top of my 5 gallon reservoir lid which I would use to test the pH, top off, and drain/fill. That hole would be "corked" when not in use with rubber plugs I had found online. I bought a 1 inch drill bit and tested the design out on a sacrificial bucket lid. The 1 inch hole wasn't big enough to fit my pH tester into, and was just too small for practical use. Also,the rubber plugs wouldn't fit properly if not painfully careful and precise with the drill bit. Then it occurred to me: the foam pool toy that I used to create my cork/skirts for the bubble cloner. You can buy thee tings at the dollar store, they are the 8 foot pool noodles that you float on (or whack hornets with) in the pool. most commonly used to assault an unsuspecting sibling or "pool rival". Anyway, I can make a 1 1/2 inch hole or even 2 inch hole, then just cut out a slightly larger sized cork of this waterproof material. That should do the trick.
I wouldn't even have to drill a hole, I could simply cut cut a rectangle out of the lid using a knife, and then just cut a thick, slightly larger rectangular cork out of the pool noodle.
I thought I'd mention this to anyone who was interested in trying this design, especially on the cheap, and didn't want to buy corks or precision drill bits. As the corks I created for my 3/4 inch holes work just as described above, I see no reason why different shapes or sizes would be any different. This should save on some effort of testing pH (lifting those lids and shaking/shifting the plants sucks) and especially on draining/filling.
For those that still don't know what a pool noodle is, it's one of these things: http://www.islandrentalservices.net/...es/noodles.jpg