The first photo shows the USB microscope I got off Ebay. $23 including shipping. Your results may vary.
. It's capable, according to the thumb adjustment wheel of 20x's to 230x's magnification. I have found that it's hard to do anything in between. Most of my photos are at 220x's or 20-30x's magnificaton.
The 2nd photo shows I believe Nitokra Lacustris copepod. This copepod came in as a contaminate in a rotifer order I received. Upon research I think I've identified it as Nitokra Lacustris. I know is a harpacticoid copepod as it dewells on the substrait of my culture vessels. It does not prey upon the rotifers which continue to proliferate the same culture vessels that I've been able to observe. Attempts to separate the two have proven fruitless as any ones which have been even hand sorted show up in the other culture vessel after 1 week. The nauplii is reported to be 40-50 microns and would fall within the nessasary size as a first food. I initially tried to culture Parvocalanus but the cultures crashed and burned in 1 month. These don't, they and the rotifers thrive.
Rotifer and copepod food: I use kelp meal(powder) and spray dried spirulina powder from FAF. These two are mixed 1tbs/ea into 1 ltr of ro water, shaken and refrigerated in a 2 ltr soda btl. Each mixture last 10-14 days. I feed 1/2 of the soda cap full per each glass gallon culture vessel every morning to maintain the numbers. When/if I need to increase the numbers beyond this I dump 1 gallon of copepods/rotifers into a 5 gallon bucket with salinity of 24-26ppt drop in a slow bubbling air line - no stone, and feed 3x's a day. The numbers explode in 5-7 days using this method. Each culture vessel lasts 1 month then needs to be re started.
3rd pic shows the highly technological culture method
. These are 1 gallon glass pickle jars which have been sterilized with bleach and a microwave oven ( while empty). The covers are polyfill in quilt form you can get at any craft store/wally world, baby crib sized. I cut it into 5" squares and use a 1/2" cut piece of 4" pvc as the collers. I got ridged 1/4" acrylic tubing in 6' lengths from US plastics and cut it into 1' lengths. The air pump is a Fusion 700 and right now I only use 1 port, dialed way down and tied to 3ea 3way valves in series. I can run 12-14 culture vessels off just 1 port, the pump has 2, with the output dialed almost all the way down.