I have a small (~5 gallon) newly set up Walstad aquarium. It seems awfully happy, but I can't seem to not kill shrimp. It's been set up for a week and a half, and is fully cycled. I've got a ton of plants and a handful of snails (MTS, bladder, and a single nerite). Additionally, I'm raising a billion little bacteria in a mat on some driftwood, more billions of diatoms on everything, and there are a number of other little critters (detritus worms, rhabdocoela, copepods, etc.). I did a full battery of chemistry tests a few days ago and the results were as follows:
pH - 7.5
TDS - 403
GH - 12°
Temp - 76°
Ammonia - 0
Nitrite - 0
Nitrate - 0
Copper - 0
Water is remineralized RO. I discovered early on (after killing a nerite) that my tap water comes with bonus copper; not much, but apparently enough. Currently tests at 0. Substrate is potting soil and fine gravel with some crushed coral. Lights are on 6/4/6/8 hours (4 hour siesta per Walstad's book).
My intent is to add a handful of shrimp, but I'm still fairly new to this, and thought it wise to have a trial run with a "test shrimp". I picked up a single RCS at the LFS. Turned out to be a berried female. The LFS person told me to acclimate via 10 minutes temperature acclimation bag float, then add some water and wait ten more minutes, add more water and wait 10 more minutes, then net the shrimp into the tank. The shrimp swum around quite a bit, and would "hitch" like it was recoiling after having run into something. It settled down after a day or so, then died the next morning almost immediately after the lights came on (between my first and second cups of tea) sitting on the bottom of the tank and sorta just tipped over onto its side.
The second RCS I got from a different source, and acclimated it much slower over the course of about an hour. I don't have a drip acclimating setup, but I do have a 5mL children's oral medicine syringe (never used for medicine) that I used to add 5mL at a time, and slowly ramping up the volume. It never really did the hitching thing, and mostly hung out up in the roots of the floating plants. I never saw either grazing. The second one died this afternoon toward the end of the siesta, also sitting on the bottom, but didn't tip over until I poked it with my aquascaping tweezers (I'm sure they have a better name than that).
Given the prevalence of copepods darting around, and the happiness and health of the snails (and now baby snails), plus the test results, I have to feel that my water is in pretty good shape. I've got multiple types of biomat, tons of diatoms, and each shrimp even had access to (but never touched) a blanched lettuce leaf, so they shouldn't be wanting for food. I have no idea how I'm killing these shrimp. Please help!