calcium reactor

do all calc reactors require a co2 tank

 

Yes they do. Cant function without one.

 

besides a reactor and dosing is their any other way to keep a good calcium level

 

It really depends on what type of corals you plan on keeping.

 

if you take the time to read this, you will understand more than you can possibly ask...
Reef Aquarium Water Parameters by Randy Holmes-Farley - Reefkeeping.com

 

acans, zoos, some sps later, and a few other oddballs that catch my eye

 

You could get by with weekly water changes with acans and zoos, but with sps you will need to dose or use a calcium reactor.