nice work :thumb_up:

your initial tea preparation seems good so you have lost yield in other steps.. i would say most probably in the manske.. i usually use twice that amount of salt/volume.. but anyway the product looks good

i have noticed the yellow color in basing step when using sodium carbonate.. and then adding few drops of NaOH solution will resolve that color although i didn't notice any significant precipitation.. i usually base my harmalas drop by drop with NaOH until the yellow tinge goes away. then i do few water washes and i make sure to remove as much as i can of the water before drying.

and yeah distilled water should have ph 7 and drinking water should be around that too so maybe your ph meter is not working well.

Here in the pic you can see what i mean by yellow tinge.. the 2 shots are just 1 drop of strong NaOH solution away