Okay... it is GREAT that your ammonia and nitrIte levels are both at 0, HOWEVER in a fully cycled tank, there IS supposed to be a reading for nitrAtes. Since all 3 of the levels are at 0, this is telling me that
NONE of your tanks are cycled right now. So you're going to want to be paying close attention to the levels for ammonia and nitrate, and you might have to do more water changes than normal to keep the levels low
As to
WHY they aren't cycled. . . it *might* be because of the General Cure medication, that *can* knock out the bacteria, or maybe because too much cleaning of the gravel and filters has removed what beneficial bacteria may have been in there, OR because you were regularly using a product that removes ammonia - this is what Snappy was trying to explain earlier - the bacteria FEEDS on ammonia, so if you use a product that removes it all of the time, the bacteria will never be able to grow, having nothing to eat. But with that said, ammonia is still deadly to fish, so it's a balancing act while the tank is cycling, and a very dangerous spot for the fish to be in, no matter how you do things. So be very careful, and try to find more advice on how to get through this process with as little stress to the fish as possible. Regardless of the
CAUSE, you're going to have to be very careful over the next 4-6 weeks, and monitor those tanks constantly while these bacterial colonies develop.
If it's it possible, ask a friend with established fish tanks, OR ask your pet shop - if they can give you some media from their tanks to help you get a bit of bacteria in there to 'seed' the tank(s). This can be a handful of gravel, a tank decoration, or a snip from the filter pad -
ANYTHING that has a surface on which the bacteria has colonized. The cycling process will go a bit more quickly if there are some in the tank to begin with (though it still won't be instantly cycled, and you'll have to be careful!). Keep in mind - if you can get something - that the bacteria are living organisms that you want to keep healthy. Treat any media just as you would a fish - don't wash it and keep it wet in it's tank water while it's being transported back to your own tank(s).
A
lot of people don't realize it, but the beneficial bacteria lives on the surfaces
inside of the tank - not in the water, or exclusively in the filter - this is why 'dipping' the other filters in the new tank(s) wouldn't have helped much. Gravel is perfectly fine, stick to what you like! I wasn't trying to get you to switch to sand (don't think you should, actually) I was just letting you know that *I* don't have tanks with gravel, so I don't have much experience on how to properly care for it. Again, do your own research, maybe post a thread on how to properly clean your gravel, etc. But be aware that over-cleaning sure can be a problem - and I suspect that in your case it probably is.
Fish pee creates ammonia - and without the beneficial bacteria in the tank to take it away as it comes, the levels of ammonia can rise very rapidly. Between the ammonia suddenly 'spiking,' and your 50% water changes dropping it back very dramatically and suddenly, PLUS the temperature in the 10g being too high - I think we've figured out why you're having so many problems. . .
I've never used those water conditioners, but I'm sure they're fine - just make
sure they remove everything that needs removing, and you're set!
I'm not familliar with your heater, but if you're sure that it is in working order, drop that dial toward the "Negative (-) sign," a bit and see if you can get the temps lower in the 10g tank - they ARE too high, and will harm your fish.
What type of tetra do you have? If we know this, we can better figure out what temp would be good for that tank.
It's okay if you're not the best writer - everyone has their talents and weaknesses! I love to write, but I can't ever seem to keep things short and concise.

Now that you've calmed down a bit, are spacing your thoughts out a little, and using some punctuation, it's been
MUCH easier for me to figure out what you're trying to say!

Thanks for trying, and not getting offended by that request! Keep in mind that when reading thoughts through text, things can get mixed up, and sometimes words come out sounding (to the reader) more harsh than they were intended (by the writer) - and the same thing is true in reverse! Try not to take things personally, and feel like you're under attack. I promise you, the people on this forum are generally
VERY nice, and they only want to help. So even if something seems rude to you - remember that it probably wasn't intended to come out sounding that way!
Moss balls need to be gently rinsed in dirty tank water and re-rolled every so often to clean them of all the gunk they collect. Make sure that you put the ball back each time with a different side facing up, as this will help it grow evenly, and keep its round shape!
Betta have very delicate fins, so if your decorations have ANYTHING that they might get snagged on, take them out of that tank right away, so that he will be able to heal properly. I'm still suspecting that water quality might have been an issue, since his fins sound very dramatically torn. I know you're doing your best, so don't take it the wrong way, but you're learning. I'm still learning, too, and have made my fair share of mistakes. Every type of fish is different, and Betta have their own set of rules. My betta tank IS fully cycled, but many people DO keep their betta in small, uncycled tanks successfully - I just don't know how to help you with that. Do some research on your own, and post a thread on
this fish's troubles in particular - hopefully you'll be able to get someone with more expertise to help you get him healed up and healthy again. Same thing applies to Goldfish - they're very unique fish that have their own set of rules that have to be followed. I don't keep goldfish, so I'm not familiar with their needs. You may want to post a new thread specifically with the goal of figuring out what they need, and how to get THEM through a cycling tank. Since they're notorious for having a high bio-load (they poop a lot!), you might need more experienced help to bring that tank and those fish through without harm.
I'm going to be very busy today, and over the weekend. I hope I've been of some help to you in getting things figured out, but please keep in mind that I am fairly new at fishkeeping, too. I don't want to steer you in the wrong direction, so be sure to do your own research and post some new, more specific, threads to get more detailed advice. Remember that it is way easier all around to ask questions about one tank or one type of fish at a time per post, than to try to sort through advice on four very different tanks at once.
Best of luck to you and your fish - and never be afraid to ask questions!