+1 DO NOT USE TAP WATER!! and don't due a water change during a cycle. just let it run its course for awhile , don't add anything to the tank. I have NEVER put anything dead in a tank ( not on purpose) and I don't "buffer" anything. My secret is I do weekly water changes ( after tank is well cycled) 10% if you use good salt everything should be fine. Dose , treat , buffer...blah blah blah. If you artificially raise one thing you lower another , I have had GREAT success just leaving it alone
JMO
BTW , tank looks great , dont worry mon it will be fine