First Time DWC Afghan Kush

Greetings All. Im having a mind issue of embracing this form of gardening. Im in a 5 gallon bucket. Afghan plant 15 days old from seedling. No rockwool cube. My water temp Im guessing is at about 73°F. My PH is kept at 6.0-6.3. PPM is at about 458. I do not yet understand how to adjust PPM. But i study more on it. Regular pump that came with bucket. I already have a cammercial one coming with 8 inch round plate airstone. Im using GH. Im currently using in the res only micro and grow ONLY at less than half strength. Do the plant look like its on schedule? CFL at about 500+ watts. Whats some of the expectations to become wiser at DWC?! Thanks in advance.

looking really good use the 3 part at 1/4 what bottles say
as the plant grows up fill the net pot.. during week if needs top off just calmag water is what i use in veg. in flower may drink whole bucket over night A must check daily thing

lot of ppl. don't have this problem tho
what happens with warm water.. at res change next day roots will turn brown start or root rot
learned the hard way
what i use and just follow feed chart ph come out right on the money ppm are low like i want don't check temp any more tea helps that
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Does topping off mean to refresh? Would i release several ounces or a few pints. Then ph a gallon of water after a few ml of cali mag, then relace what i drained?