Hi sedey! Welcome! Yeah, a week is pretty short for a tank to cycle, my suspicion is that it's not fully cycled yet, too. Watching the test kit results everyday - did you see spikes for ammonia that leveled off and started back down - then an overlapping rise in nitrites that eventually leveled off and fell? You should have been able to see that happening, since you tested every day.
Ultimately, when you're sure the tank has cycled, you shouldn't add more than one fish at a time. Each time you add a fish, the tank will go thru another mini-cycle. Did you use decaying seafood to cycle your tank? Clowns are pretty hardy, and that would be a good first fish to add after the cycle is complete. Only one clown in your tank, of course.
After adding a fish, if everything goes well and testing show good results - give your SB a little time to develop. You'll probably go thru another algae outbreak in this period and possibly a
cyano outbreak when the algae starts to die off. You can reduce the photoperiod to discourage the algae problems during this time, because your fish don't care about a shorter photoperiod (but corals would). I'd say in a couple of months, it would be pretty safe to add certain types of corals - mushrooms, for instance. Don't try for an anemone until the tank has been running for a year. Certain kinds of fish also require a mature tank (anthias and mandarins, for instance). You'll want to avoid those fish for the time being also.
I know it's frustrating to go thru the waiting, but losing fish and corals is even more frustrating. Plus, if you jump too fast, you'll end up in a crisis situation and be spending a zillion hours on maintainance and efforts to keep everything alive and healthy. Not to mention the stress and worry for you.
There are a lot of great things you can do during this period. One good one is to research fish compatibility and plan out your tank. Look into coral warfare issues;
soft corals put out chemical warfare stuff that will hamper hard coral health. Post a thread on suggestions for fish that get along and would be happy in your 20 gal.
HTH
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