You got a lot of work to do. Anyway, now that you on MASA, keep on asking questions.
Anyway. The thick layer of crush coral substrate. It looks cool at the moment. But in future, that is where all the detritus will be trapped, causing future phosphate and nitrate issues. Rather take half of it out. Or try aragonite (expensive) or play sand (cheap but dirty). If you go playsand, you need to wash it like 100 times. It is dirty.
I did stop by Dorry Pets this afternoon to pick up a new pump for myself. Anyway, did look at the options, and had a quick chat with Lanzo. Yip, that small usmp you got with the LAVA rock, its good for fish only systems. But as soon as the ladies in the office see one day some nice corals, then you need to change. I mean you need to change the sump.
I do like my DSB. Its cheap and when properly sized and setup, it does its job naturally. but you can not go for a DSB. So you are the second person to whom I give the option of the NP-Pellet reactor as alternative. It does its job, and if it can do as promised, then that the answer to all those small sump designs with the little glass doors.
First, you want water. NEVER USE TAP WATER. You did mention the place you bought the tank said to you that you can do your top ups with tap water. Well, you know now better. So the first thing is a RO unit. Maybe ask the sponsors for a RO unit that you can use at the office that give RO water for inside tank, and drinking water for the people outside the tank. That be cool.
Next, live rock. Depending on the quality of the rock. the ladies of the house want to see fishes. And you need to keep them happy. So get good rock that is already cycled. I saw the rock at Dorry that they got in already some months back. Rock like that is already cycled. And provided you do transport them in a bucket under water from there to the tank. Then you should not run into major cycle issues. (I sound like a rep for Dorry. Sorry, I'm not.)
Your ATU, is the next thing. Get a proper one. and the RO drum should be big enough for the weekend.
Also, visit Idol Marine. They just of at Allandale. Other sponsor that you should visit is Pet Stop. Anyway, those 3 shops are the ones that I visit.
And that glass sliders on top of the tank. Remove it. Glass sliders at 3mm is anyway too dangerous to use. You will break it.
Feel free to come around and check what I done. Its always good to steal with the eyes.