To be honest mainly just on observation of the corals, thats why I started with 5ml of each at 1st, then upped it to 10ml of each, remember I only dose it once every 2 weeks for know but will be upping it a little in the near future. I like to do things a little different, experiment with things a little different than the norm and observe the reactions of the corals. My tank is heavily stocked with corals and fish so I’m sure the 10ml every 2 weeks is less than I could be adding but seems to be enough. Here’s a couple recent pics just in case you haven’t seen the cluster of corals I’m dealing with.