Once every few weeks, under the Equipment Forum, Carey will setup a group buy through BRS. In order to join the group buy you must first register at the BulkReefSupply website. No special registration, just the normal stuff.
Once you do that, you can PM Carey with the SAME e-mail address that you used to sign up on the site. After about a week or so, Carey will send in the final submission to BRS with all of the e-mails to verify who is involved.
Once the groupbuy timeframe starts, you will input your e-mail / username on the site, and then you will be able to see the discounts available.
You DO NOT have to buy anything. Some people go just to check out the deals. Once you join a group buy, you become a preferred reefer on BRS and get to enjoy lifetime discounts (not as good as during the group buy timeframe, but still good).
BRS doesn't sell livestock, it is mainly equipment. Any of the suppliments such as GFO
and calcium usually have a really good discount, basically anything BRS has their name is is discounted well. Skimmers have some good discounts, bulbs are a few dollars off, etc.
I did one so far, and really liked it. If you don't find anything immediately, you still have the Preferred reefer status at the end and will get lifetime discounts from the site.