I only use Dr. Tim's One & Only. Read up on them at their site and it just sounds like they know what they are doing versus the other companies. I have used their product three times now and it worked, as they say it will. They have Reef and FOWLR
(not sure what the difference is).
If you are going to order from them, mention that you saw that they had a 30-33% discount about a month ago and ask when are they going to do that again. They might just give you the discount. That is what they did for me this last time... They had a weekend deal that I did not see until Monday morning. I started to order, because the discount still showed, but it would not give me the discount at the end. I stopped my order and they contacted me a day later asking why I did not complete the order. I explained and they said they would discount it. They did.