Advice for a newbie...here is my setup so far

[RPatsula]

Hello everyone, I am new to the saltwater aquarium hobby. So after going through CanReef and several YouTube videos here is what I ended up setting up. I have attached some pictures as well.
230 gallon tank 8’’ by 2’’ by 2’’
100 gallons sump
vertech 280 skimmer
2 eco-tech MP 40s
2 eco-tech MP 10s
4 eco-tech Radeon lights
200 pounds of live rock
Vertech RO/DI water purifier for auto top up and water changes.

After letting the aquarium stabilize for a month, I put in 40 hermit crabs and 40 snails. Then after another month I started putting in some fish as well as some coral. Here is a list of the fish and coral I put in(they have been in for approximately one month)
4 clown fish-3 are still alive
3 cardinal fish-all are dead
1 diamondback goby-dead
12 cromis-6 still alive
4 peppermint shrimp-2 still alive
1 regal tang-dead
2 Zoa colonies-alive
1 green plop-alive
2 anenomes-alive
As you can see I seem to be having good luck with the coral but really bad luck with the fish. Initially I think I was not feeding them enough, so that is why I think they died. Now I am feeding them frozen shrimp twice a day. Also as a newbie I didn't realize I had to feed the anenomes but now that I am they seem to be doing a lot better.
Since I am in a wheelchair, I also created a feeding tube system, to help me feed my fish. I made a mistake when I built this and used brass ball valves. I am in the process of removing them and putting in PVC valves. Once this is done, I will post pictures of this as well.
Here are some of my questions. I have a hard time reading my refractometer. Sometimes it says my water is at 1.02 and sometimes it says it's at 1.025. How important is that fluctuation as well as what should I really have my water at. This also brings up another question, I am thinking of purchasing a Neptune apex controller with a PM2 module as well. Would that be a good choice?
It would be nice to know why the fish just seem to be dying? I have no idea what I am doing wrong. I am doing about 15% water change every two weeks and I am using the prodibio stuff as well. I guess what I'm looking for is a bit of guidance and advice. I also have a fridge full of beer if you want to come over to share some of your knowledge and check out my set up.

Thanks in advance
Rick