Is your tank 4'? It doesn't look like a standard 6' 125 but more like a standard 4' 120. But anyway, your alk
is extremely high. 300 ppm
= 16.8 dKH
. I would suggest just letting it ride as is for a few more weeks and as the tank cycles and starts to stabilize the alk
should drop on it's own. What brand salt are you using?
I would also cut back on the water changes. 20% every week is fine.