test your water. post parameters. how long did your tank cycle? what testing kit are you using? you said your rock was in a 20 gal tank, how many pounds of rock do you have? what are you using for water flow? where are you getting your saltwater from?
DUDE this is going to happen
1. you get the dwarf lion and pair of clowns, dwarf lion doesnt eat anything and dies. Alot of dwarfs will not eat in captivity. IF you do buy a dwarf make sure he is eating first. tell your scamming LFS to feed the dwarf in front of you.
2. dwarf lion eats clowns and inverts. Sounds like you did not do your research. dwarfs will eat anything they can fit in their mouth. Even though u think you have enough hiding spots, but if the dwarf is on his hunt, he will wait outside the hiding spot and eat your fish. if you get a dwarf, be sure to get another fish bigger than that. LFS are liars unless you go to Ocean gallery in Jersey. a LFS told me that i can keep SPS under pc lighting. LFS told me that i can keep a volitan lion in a 28 gal nano.
you need to understand something. CANISTER FILTERS SUCK. be prepared to change media every 2 weeks. you are upset about 1000? man check craigslist and other forums. u could have gotten a 265+ complete setup for that much. I do not know why you intended on saltwater if you didnt think you were going to spend that much. Fresh water is a lot cheaper. get some pirannha.
scratch the cfanister filter, you can still return it if its after a week even though it is used. if you cant, your LFS ripped you off. Even though they already did.
Get a CPR HOB refugium, get a aqua C remora HOB protein skimmer. TRust me that is more than enough. The light fixture you have, is it metal halide?
you said the worst case scenario, bring the fish back and trade them. from a LFS THAT MEANS THE FISH WILL NOT SURVIVE.
looks like u have never had a salt water tank setup before. you have a 20 gal tank as you stated. start with that then move up to 40. i started with a 29 hex, sold the hex bought my nano which is awesome, bought a 75 gal, now working on my 150 and i still think i am not ready for the 150. everyone on here has ALOT of experience. i guarantee they know alot more than you do since you want to keep predator fish in your tank with smaller fish and expect no one to die. They all have been thru the worst case scenario. Chances are - you stick with your canister filter, and watch the nitrates build up. you will stop changing media and get massive hair algae. THAT HAPPENED TO ME. I WENT THRU THE CANISTER FILTERS THEY SUCK. crimzy, rotary, mbosswell, they all know what they are doing. and when they dont, THEY LISTEN TO ADVICE. i regularly take their input when it comes to making decisions. Go ahead continue with the setup that you have, go thru a tank collapse. We will see in SWF "Help me my dwarf lion ate my fish!" "HELP HAIR ALGAE EVERYWHERE!" "HELP NITRATES WONT DISSAPEAR!" "HELP IDK WHAT I AM DOING!?!" "HELP I GOT STUNG BY MY LIONFISH!" i am surprised that rotary didnt post here giving his smartarse comments. lol jk rotary.
listen to others, they have all been thru experiences you couldnt even think about. I gave you suggestions that I think ytou should follow. keep a dwarf lion, by all means do not get a fu manchu they require experts, not someone who wants to put a lion with fish smaller than his mouth. sounds like your LFS loves making money off of you.
GO SLOW.