no worries! glad to help.

the soil should obviously be flushed if there is any sign of problems. other than that, it won't hurt. i like to flush them everyonce in a while just because (the salt build up, like you said and such). that's veg or flower. i would flush intermittently.

for the salt buildup you can put a drop of dish soap into your feeding solution to help combat that.

observation is the key. each setup/plant are gonna act different. so YOU will be the one to know when and what is going on or needs to happen. it'll come with time.

good growing!

-shake