How to make a tank as low maintenance as possible?

[HusbandsTank]

Due to my husband being deployed I get to maintain a saltwater tank I know little about I was wondering if there is anything else I can do to make it low maint.

I have...
20 gal high
2 powerheads
Submersible heater
1 yellowtail damsel
Some live rock
Some snails
2 corals (no idea what they are)
Single led light (unsure of the type but i think its 50 wats with 3 blue leds and 2 white)
Glass top left halfway up when I am not traveling
Over the edge filter that needs replaced because it was leaking (suggestions here would be great!)

I want to travel for up to a month at a time. I have a friend who will help when I am away but I dont want to overwhelm her. My plan was to do a water change (about 25%) before and after my trip and ask her to come weekly to top off water and feed the fish. I was told the fish can eat other things already in the tank? So he doesn't need to be fed too much.

Also, it would be cool if the tank was in even better shape when he gets back. Are there any corals you can suggest for a noob? Fast growing and tolerant?

I know this is a lot so thanks to anyone that gets through all of that!

[TommyP]

Besides wiping down the walls, topping off rodi water, emptying my skimmer, and water changes theres not really much maintanence I do to my tank, however it's only been up and running for about 6 months. Maybe someone else can chime in with other ideas but as long as you do your water changes you should be okay.