Hi Alex
Great names for Dwarves lol.

TBH you haven't had the tank running for very long so I'm not 100% sure that that will be sufficient time to mature before you get the Dwarves but like I say it's a bit different for a Dwarf tank. If you have had the filter media in your other tank it should help. Have you been testing the water regularly? The best thing that you can do when you get the Dwarves is to regularly (2-3 times weekly) check the water especially for nitrite and ammonia. Adding all that brine shrimp can upset the balance as I found.
I had a hang on filter once upon a time and although it seemed good to start with it became a real pain and got clogged with algae. It was a filter/skimmer all in one. Is yours a Niagara by any chance?
I have got three lots of brine shrimp hatching so that I have a constant supply. I also have baby Reidis and feed my other tanks. I would definately recommend that you keep two on the go in case one lot goes wrong (as I have found out). If you put one on in the morning and one on in the evening that will work. I put a bottle on about 7 in the morning then it is ready the following evening. The second batch I put on around 6-7 in the evening and it is ready the day after next in the morning. Are you going to use an enrichment vessel?
Joanna x