cheap for a 160 gallon mix. You also get a 5 gallon pail to use for whatever after.
https://www.amazon.com/Instant-Oc…Z7MB3YV309
The non-reef version is also available. 160 gal mix for $28.61
https://www.amazon.com/Instant-Oc…r=8-4&th=1
Same price at Chewy
https://www.chewy.com/instant-oce…/dp/165469