Watched the video (great one btw!) but made me think of a couple questions if you don't mind me asking haha
1. You said you're STARTING with Instant Ocean but will be switching, why? I'm using Instant Ocean and wanted to stick with it cause it is cheaper haha
2. Do you still just buy distilled water or do you have an RODI (if no RODI why not?)?
3. How many lbs of rock do you (or did you?) have in it?
THANKS! P.S. that is a TERRIBLE video and I'll be doing a follow up video about why it's a BAD IDEA to do a "BUDGET" Tank! I've learned so much with all my different tank builds along the way (and that rock scape is horrendous too!) But no one starts as a pro and in this hobby you are continually learning and things are continually changing.
In a reef tank, it's best to use reef specific salt. The Instant ocean salt I started with wasn't infused with the added minerals for Coral. One of the reasons frequent water changes are vital in reef tanks is to supplement the minerals and nutrients being used up in the water by the Coral. In your fish only, Instant ocean salt is just perfect. But in the video, I was going to be keeping Coral in the tank so would be switching over to a reef/Coral specific salt.
I do not have an RODI because I've always only kept nano tanks. So it's easy for me to just buy pre-mixed salt water from my local fish store every week. In my 10 gallon tank, I'm currently doing 2 gallon water changes weekly and I just take my empty 2 gallon jug to the fish store and they fill it up for about $4. No mixing or RODI needed. For top offs when water evaporates, I usually use store bought distilled water like in the video, however my current 10g setup has basically no evaporation so I don't need to top off. I can also buy RODI from my fish store for about $0.50 per gallon if I wanted as well.
It is recommended that you do about 1 pound of rock per gallon so in a 55 gallon that would be about 55 pounds of rock. 20 gallon = 20 pounds of rock. This helps with biological filtration for your beneficial bacteria to live on.
In that video, I placed huge large boulders of rock, but you definitely want to break those larger pieces into smaller pieces and shape it better as well and glue/putty the rock together for stability! I was horrible at rock scaping but I'm finally getting the hang of it!