Rube_Goldfish

The intens of light traveling through water is halved about every six inches (if I'm remembering correctly), but it travels through air much more efficiently. If raising the light would more evenly or more helpfully distribute the light in your tank, I say go for it. Three inches isn't even all that far removed.

If the lighting is too high for anubias, you might try Hydrocotyle tripartita "Japan" or Monte Carlo, both of which like higher light and can grow as epiphytes, though attaching them to that rock might be a real chore.

If you're feeling adventurous and the local laws allow it, you can likely find some kind of daphnia in any healthy body of freshwater. Just bring a net and bucket. And maybe be prepared keep it separated for a while as you watch for unexpected hitchhikers.

I guess I'm just living in the past! The glass seemed like a pretty clean break. I vacuumed and turkey baster-ed the pellets up as best I could, then added some spare sand into that spot to bury any I missed. After that I realized I could have used a magnet, but figured there likely weren't any left, and if there were, they were already under the sand.

Thank you, yes! It looked just like that one! I'll clear out all of the balls but will otherwise confidently move the new puffer into this tank.

I should add more detail: this tank held, up until sometime yesterday, a single pea puffer; we found her dead yesterday evening. The parameters tested out a little high on GH, KH, and pH, but otherwise fine, and the fish had no obvious injuries or illness. I chalked it up to the too-high GH/KH/pH and did a 90% water change in the anticipation of moving another pea puffer into this tank. Now I'm wondering if the previous puffer ate one of the small metal (?) beads that fell out of the bottom of the thermometer. I guess I'll have to fish them all out before putting another puffer in there.

I have a tank in which I just discovered a broken glass mercury thermometer. At the moment, there are no fish in the tank, but the bladder snails and isopods* don't seem affected at all. I have Sera multi test strips and the API master test kit but obviously have no way to test for mercury. Can I use the snails as the canaries in the coal mine? If they're fine, fish would be fine, too? *I think, anyway; they're small white dots zipping around.

That's a good idea, too. Mine are about the size of a big pea, on average.

And that's also how TDS meters work: measure the conductivity of the water and extrapolate that out to the "impurities" in the water.

I mostly have the same: lots of small bladder snail shells. While a cat litter scoop would be too big, I think, to fit between plants and hardscape, I wonder if I could use a slotted spoon? Or maybe just a coarser net.

My adult male Apistogramma cacatuoides is headfirst into a gap between stones: You can just see his tail fin there. Can fish get out of small spaces that they can get themselves into, or do I need to rescue him? If the latter, any advice on removing the stones so that I don't hurt him?

As your total plant biomass grows, you'll need more fertilizer, but I agree with @Tlindsey to keep doing what's working, or at least to make changes slowly. Maybe 18 drops for a while to see what happens, that sort of thing. It works in reverse, too; after a big plant trim, you'd need less nutrients than before.

Related to this topic: does anyone have any tips or tricks for cleaning up all those shells? I have a lot of old shells, and I guess I could just leave them to (slowly!) dissolve back into the water column, but in the meantime, they're a little unsightly. So far I've used aquascaping tongs, which take forever, and a fish net that I swish the sand back out of, but that's not much faster. Any better ways I'm not thinking of?

I don't know Iowa geography all that well, but ACO has a club finder: https://www.aquariumcoop.com/apps/store-locator

There's a channel on YouTube, Aquarium Plant Lab, that does a lot of emersed growth/propagation that sounds like it might be something you might be interested in.