You should see a daily drop in your ppm as the plants eat the nutes. When I run DWC I generally top up and check the ppm every three days. Using RO that's about 5ppm means I don't need to factor in the ppm of something like tap water to figure out how much the plants are eating each day.
When plants are small they eat so little that folks who follow the directions are basically throwing away a fresh batch of nutes every week for the first month or so. Same with following their feeding instructions. With AN nutes they say to use 4ml/L from the start to the finish and I guarantee that you'll burn the hell out of your plants at those levels. Especially if you use a lot of their supplements as instructed.
I'll start well-rooted clones at about 350pp, then as they start showing real growth bump that up to around 500 then by the third week be up to 750 or more depending on the strain. With kush and most indica dominants they can handle 1000. Using the 3-part nutes I feed at a ratio of 3-3-1, G-M-B. About a week before flipping to 12/12 I'll increase the Bloom portion of the nutes and add a half dose of Big Bud to "prime" the pump. Tried the Bud Ignitor on a couple plants and it does seem to increase the bud sites and ultimate size of the colas so I plan to experiment with it again. A friend who grows monster plants outdoors in Ontario swears by the Bud Factor X for lots more resin but that's another pricey product I'll try a small bottle of for my next run. Big Bud, Rhino Skin and a wee bit of any CalMag is all I've used for years beyond the base nutes.
Keep track of how much your plants eat daily the week before you flip then follow that up as they go thru the stretch. Their daily feeding can go 3 - 5X what they were eating their last days of veg then it drops back as the stretch ends. This is a critical time and when you should have everything maxed out like feed, light and CO2 if you have it and will definitely impact your final yields.
