Why Wall Turn white with Sodium Bicarbonate Options

[white horse T1]

somehow whenever i add sodium bicarbonate to the pail i used to age overnight with anti chlorine/chlormine treament, my tank has traces of white coating the tank wall and even the sponge. but they got dissipated after a day in main tank

why? is it that i put too much or the sodium bicarbonate did not dissolve properly?

[white horse T1]

I usually add sodium bicarbonate directly into the main tank.  Here's the calculation for me to up 50 ppm usually after I changed water, my water from tap is very low so usually I need to buffer twice.

57L water 5g of baking soda

After Change water on Saturday  morning I add 5g to buffer
Sunday night I do a 5 in 1 test and ph up if needed, but usually need to up PH a little and another 5g to buffer
Wednesday / Thursday another 5 in 1 check, but usually it is fine.

Following advice from the bros here I no longer age water, but mix my aqua+ in the jelly can before it goes into the tank.

ok i just want to know if anyone see white stuff in the tank after adding sodium bi...regardless of amount.....