New 75 gallon tank NEED HELP

[Aqua Sanctuary]

Ok... I bought a new 75 gallon tank.
The tank is empty and just sitting in my room.
I will be keeping a baby clown knife in there until he grows a bit, then he will get a bigger tank. There will also be a tire track eel, and mabey a bircher.

My issue is that i am stupid.
I'm not sure what filter to use, what substrate, what heater, and if i need a power head to add circulation/water flow. I have no idea what i need. My baby clown knife is in a 20 gal planted tank at the moment with some gouramis.

I have an assortment of plants, driftwood, and rocks to use in the tank but im not sure if sand or pebbles would be best. any ideas? I want the eel to have a nice substrate to dig up and hide in.

I was looking at a bio wheel set up, but also I was looking at external pumps. What is the benefit of either? I have heard that power heads can help with circulation and aeration. Do i need this? Most of the fish I will keep are labyrinth fish and do not need the extra aeration, but need the cleanest water I can offer. Help?

Any information on these topics would be greatly appreciated!
thank you

 

[barley pop]

for filters i would use an emp 400 (or ac 110) and a rena xp3

for heater the best one i have found is the stealth (just get the size rated for your tank or larger)

substrate use what you like best

powerhead you can use if you like but i don't think they are required by any means

 

[DasArab]

Eheim 2217
Eheim Ebo Jager 300watt
Sand

 

[Merbeast]

magnum 350 "pro" setup with bio wheel. Good, clean fun

 

[Jkoziatek]

emp 400 isnt enough on a 75... you're deff wanna do with some typa canister as it will move the water better within the tank