I used Cloram-X for years, but it is not nearly as cost effective as Seachem Safe.
As previously stated:
10 lb's of ClorAm-X will treat 37,588 gallons (2.1 mg/l chlorine, 3.2 mg/l chloramine) so even if I was overly generous & doubled the water volume based on 2mg/l (my local tap water level) of chloramine (actually it would only be treating for 1.6 mg/l) I would be looking at approx. 75,000 gallons vs. 400,000 gallons of water using the 4KG container of Seachem Safe.
That's quite a substantial difference ......