I don't think a straight concrete container 1inch thick will be strong enough. I recently built a 3.6mx0.9m by 1.2m deep fishtank out of structural plywood and hardwood, and did all the design calculations. It is possible to work out the strength required, although it's a little difficult for concrete, as concrete is very brittle and has a low tensile strength. The average force on the wall will be about 230kg/m with more force near the bottom and less near the top (however, tanks are usually cross braced at the bottom and open on the top). Think about the tank as a 24" slab with a 1000lb weight in the middle and think how strong it would have to be to hold without cracking. A circular tank will be stronger, and putting reinforcing wire, rod or fibre will make it more practical. Chicken wire wouldn't do a thing, but fencing wire, hardware mesh or fibreglass mesh would probably work. You should put the reinforcing on the outside of the tank. It's going to weigh a lot! As an alternative idea, you could use a foam core of 2inch polystyrene boards with (3?) cement-acrylic and fibreglass layers on the outside and inside with through links made from light wire. It would weigh a lot less and it's really only the surface that you need to be concrete.

There are fish for sale in the 3 to 5 dollar range at Petco....Lots of various damsels as well as a few gobys.....SW is not any harder to maintain than FW is IMHO....I currently have a 10 gal in th works as well as a 90 gal both reef type tanks.....I got started on what is probbaly the hardest type of setup (so I was told) and thats a Pico reef tank with one small neon goby.......and its been great, and no harder than a betta tank......To be honest and this is only my opinion, save the money onf canister filters etc, and go with a tank with a sump or refugium, and lots of live rock and a good live sand bed. The live rock and sand will do the majority of your filtering. A skimmer is nice to have but certainly is not required......A small Pico type reef tank without fish, is about as hard to care for as a house plant that you have to water. There is so many inverts out there that can make a very interesting and good looking setup that odds are you will not miss any fish not being in it. Just to see if yuor cutout to fool with SW wihtout getting into it over your head, setup a simple 2.5 Pico or even a 10 gal reef type tank. Use a Aqua Clear HOB filter (a 50 or 70 size) for the 10 gal, and remove all filter media, and fill the filter chamber up with small pieces of live rock rubble.......Use 1.5 to 2 pounds of live rock per gal of tank size, and keep your sand bed to 1" or less....Really no need to have a deep sand bend in a reef type or even a tank with just one or two fish. In a 2.5 you can easily place an algae type eating snail (cerith snail) and 3 or so small blue leg hermit crabs, a small brittle starfish, and load it up with lots of polyps and mushrooms etc, and just set back and watch it mature and grow......Do a 10 or 20% water change once a week, and top off daily as needed with RO/DI water......Good lights is a must and lighting on a saltwater setup is much more critical than on a freshwater setup, unless its fish only.......If your local store caries fully cured LR, you can buy rock to suit, and live sand from his tanks, and also premixed saltwater, some shrooms etc and have it setup in no time, without a long cycle time if things are already properly cycled and cured. I have less than 100 bucks in my 2 gal Red Sea wave tank pico with filter lights and inhabitants, and close to $150 in my 10 gal including a AC70 sized filter/fuge, 96 watts of lighting, moon lights, live rock, live sand (all fully cured) and a heap of shrooms and polyps, and two small $3.49 domino damsels and one $7.99 Neon Goby from Petco......all doing just fine.........Can't say what the 90 gal is going to run yet as its still in the works but its in the 4 digit bracket already, and still not completed. You can buy RO/DI water at most LFS, and already premixed saltwater. RO/DI around here is less than 50 cents a gal and premixed SW is about 70 cents a gal........LFS will tell you that you can not keep SW or RO/DI water more than a day or two, but thats a bunch of nonesense. I was buying 5 gal of SW and aerating it with a airstone for a month and have not had problems...RO/DI just store it no aeratin needed....Keep in a dark cool place and they both will keep fine. YOu also need a hydrometer to keep an eye on specific gravity, which again is only a one minute afair and once you get to know your setup for the most part can be done very infrequently......Go for it, SW is much nicer even without fish.

I actually do grow curry leaf plants and I have experience in cold weather climates as well as warm. First of all your pots are fine for that size seedling. Using too large of a pot often leads to the soil staying too wet and then the roots rotting. On the flip side be careful with small pots and bottom heat, as the soil may dry out too quickly. The heat mat should be at a very low heat setting. Curry leaf plants also don't like to have their roots disturbed and since they are trees they do a lot better in a taller pot. I start them in 2 inch talk pots or I cut the tops off of plastic drink bottles, drill some holes in the bottom and I have an instant tall pot that gives lots of room for root growth without having so much soil that the pot stays wet for too long. And this way you don't have to repot as often, which they don't like, they go through a shock period when you disturb the roots and stop growing for a bit. Anyway for lighting, yes in a colder climate the plants go semi dormant and growth slows down. Make sure the temp is never below 60 degrees and I have had good luck over wintering them under 2 T8 fluorescent lights ( one warm, one cool). They don't put out a lot of heat, they are inexpensive and available in the hardware store here, and sufficient to not only keep the plants alive but to grow as well. Curry leaf plants love heat, but seedlings are very delicate. Also don't be surprised to lose some. I find that curry leaf seeds germinate readily but not every plant is strong enough to make it. It is best when one seed gives one plant. Sometimes you will get 2 or more plants from one seed and those plants tend to be not as big or as strong. Good luck and let us know how it goes.

Rolling on down.