To OPJust to name a few brands. I listed a few below. The Brightwell has iron in and I believe the Korallen doesn't. The price ranges differ allot on brands. If you have never replenished them, then you will see immediate results in coral color....within several days. Once you start dosing over a couple weeks you will be amazed of the difference. Its easy to see in any coral IMO. Especially LPS and SPS.
Brightwell
Korallen-Zucht
Tropic Marine
I feel I have excellent growth and colors, and if it matters, I use the Brightwell Amino Acids and TM All For Reef to replace trace elements