i found my tetras swimming about the tank this morning, the trauma of the algae removal chemicals having worn off finally. later in the late afternoon i performed another water change, not really to dilute the chemical, more to clean up the cyanobacteria that have quickly grown back since sunday's cleaning. i was afraid this would traumatize the fish once more, but they didn't seem to mind, moving to one side of the tank while i siphoned the other. afterwards they were swimming around the aquarium as if nothing happened, and i sprinkled a few fish flakes as a treat.

this morning was the coldest day so far this year, with temperature in the upper 30's. out in the suburbs there were frost warnings, but i'm not sure if cambridge was affected. there's nothing really left in my garden anyway that i want to keep; i just need to go back sometime this week and cleaning out some more dead plants, maybe prune back some perennials in anticipation of the coming winter.

the cold weather dampened my enthusiasm to go outside so i stayed indoors all day. not that it was any better, but at the very least it was warmer (68° and dropping). i had thoughts about getting some groceries but i'll do that tomorrow when the temperature is supposed to be in the 70's. i still haven't turned on my heat yet. usually that doesn't happen until the final weeks of october, but i personally like to hold out until november.

i spent most of the day studying for my ham radio exam. i take a practice exam first, and then study up on any wrong answers. it's almost like a game, my goal is to get a perfect score. so far my best was 3 wrong questions out of 35. i haven't studied for an exam since college. the internet was just starting back then; nowadays, when i have questions about something that the manual doesn't do a good job explaining, i can easily just google the topic to get more info, anything from a wikipedia description to a youtube video. it's a great way to study and i feel like i'm learning even more than what's prescribed in the study manual.

i listened to the minuteman repeater chat group (a net in ham radio speak) tonight on the belmont repeater, and got my father to do the same. they started by calling out all the linked repeaters in order, asking if anyone was on. most of the repeaters went unanswered, but there was still enough people around to have a group chat. the topic of discussion was how to get young people interested in the hobby, when the internet and smart phone is more accessible.

li came home around 9pm, with a suprise guest: LJ, my chinese astrophysicist roommate from 5 years ago. i knew she was in town for 2 weeks because 1) she and my roommate work in the same department back in shanghai, and 2) she's currently living in the apartment above my grand uncle. i thought maybe she'd contact me to at least say hi, but that never happened. she also invited li to dinner at her place yesterday, which hurt my feeling a little bit, even though i probably wouldn't have gone even if she did ask. LJ is the same roommate who blew up my microwave, and also the one i brought to new york city to see the mermaid parade. she still remembered that parade (i'm happy it made such an impression on her), asking me if i went this summer. it seems like she had fond memories of boston from her 2 months here. another one of her memories was seeing the 4th of july fireworks, which she told li was a must-see. now she's back in shanghai, married with a 2-year-old. this trip was one of the only two times she left the country in recent years. we all chatted for a little while in the living room before li walked LJ back to her place. he came back a short time later via bicycle.

i did some research for li today and recommended he get a refurbished canon rebel T6s (760D) along with an EF-S 18-135mm IS STM lens. it'd set him back $800, but it sells on amazon for $1000, so he saves $200 going refurbished. canon factory refurbished is as good as new; i bought my 60D and 18-200mm lens as refurbished (although the 60D/18-200mm i have now are new because i lost my original back on the highway of litang, western sichuan). i suggested he wait until black friday and see if there's an even bigger sale on the camera & lens combo.

the T6s is a little over 2 years old (compare that with my 60D which is 7 years old), and is a great camera. it's the more expensive version of the T6i, and includes an LCD info screen and a few additional minor features. design wise it resembles a miniature version of the 60D, except the T6s has half a decade's worth of new camera technology upgrades, including additional cross-type AF points, enhanced ISO (up to 12800), touchscreen LCD, and wifi/NFC. the only thing it's missing is a custom dial mode and a slightly slower fps (5.0 fps compared to the 60D 5.3 fps). if i had the money i'd be tempted to buy just the T6s body (though an STM lens would be good for movies; canon refurbished sells just the body for $650); it'd be nice to have two working cameras so i don't have to be switch lenses out in the field (though i'm used to it by now). though not a big deal, i've recently noticed a few dead pixels in my 60D.

taking the ham radio practice exam in bed, i finally managed to get a perfect score on one of the tests. i'm at the point where i'm pretty sure i'm can get the exam tomorrow, but for pride reasons i want to get a perfect score.