I've seen timed automatic dosers, does anyone have any experience with these? Is there a general rule of thumb of how much to dose daily? And for calcium would it better to just get a calcium reactor?
I prefer dosers over calcium reactor. You will have to dial in the amount you dose based on how quickly your tank consumes it.
You have to test your tank parameters see how much your corals consume in one day then based on your solution find the volume needed to dose. Set the pumps to dose it through out the day in small quantities. Continue to check parameters and adjust accordingly. You'll get it dialed in in no time.
Also I was thinking of getting a protein skimmed but I'm on the fence because it's only 10gallons and I'll be doing water changes and algae scrapping 1x a week.
I would recommend a skimmer. Nothing is better than removing toxic compounds out of the system before they even have time to be taken through the nitrogen cycle. If you want to grow SPS you'll need an ultra low nutrient tank. With a tank volume that small you can be highly successful and economical just to do large water changes to export nutrients and restore trace elements.
I've had coral before with no luck of keeping them alive so I'm a little paranoid.
SPS are considered to be the apex of the hobby, If you've had trouble in the past with keeping corals alive maybe start with some soft corals to get your regimen ironed out with stable parameters.
My recommendation would be to drop the auto feeder, until you have a feel for your nutrient level in the tank. Keep the auto light timer and ATO. Invest in a skimmer and doser pumps. I recommend the BRS 2 part kit. Comes with all the chemicals mixing jugs and 2 pumps.
Do frequent water changes, learn the reef ways with soft corals then once you get in the groove you go SPS dominate!