Can I switch line on my pump and push out water for nute change?
You bet. It's just a small pump that goes on the end of the drill and takes standard size garden hose fittings. On the end that goes in the tub where there are roots I wrapped the end with mosquito net and secured it with a small hose clamp so it doesn't suck any in. It pulls pretty strongly and I can empty a 50L tub in just a couple minutes. You have to hold the pump securely when you pull the trigger or it will spin around. I found out the hard way.
Yeah I figured out as well that AN wants you to use way too much nutes, i use half strength base and full strength supplements, I have had no problem this way
That's about the way I do it in soilless but will go up to 3/4 strength if the plants are larger and growing rapidly. Depends on the strain too tho. My afghani kush is a real pig and can take a lot more than some where sativas can easily be burnt at much less. I'll feed, water, feed usually. I find 4gal pots about right and take 4 days to dry up enough to need another watering/feed.
With DWC I go by ppm. Fresh clones get about 300ppm so 1ml/L gives about that then I add nutes to it to raise the ppm iin stages as the plants really get going. I generally don't do a change until after the stretch then run lower ppm than what I was running before flipping.
To find out how much the plants eat daily I will go about 3 days after the last top up. Top up with RO water only, allow time to mix well, then test ppm and add enough nutes to get it back to my target. Dividing by 3 tells me how much they ate daily. For example I had a bunch of plants that were dropping the ppm around 50/day then after the flip it went up to 250/day so needed a lot more nutes added with a top up. As the stretch slowed the drop slowed too until after the flip it was down to about 50 again. Then that slowly began dropping as the plants got closer to the end. I'm sure that is why it's best to lower ppm after the stretch to help prevent salts building up in the leaves leading to toxic salts buildup and burnt crispy leaves.
4L jugs of AN one of each just under $2000 CAD.
So 12L of nutes and gold plated supplements?

That seems like a lot of money for nutes. I just got 4L jugs of the 3-part for $40 each, $90 for a 500g jar of Big Bud, 1L Rhino Skin for $40/L, Small, 250ml bottle of Bud Ignitor was $34, (ouch), 1L OverDrive on sale for $23 and a L of GrowTek CalMag for $20. Other than the Ignitor I'm good for 3 years or so. Not changing out my DWC every week saves a lot of nutes.
A buddy bought all the bells and whistles and destroyed two large crops trying to use them all then cut back to about the same I'm using and things went great. He's running a 10x10 flowering tent with each side having an 8 plant RDWC setup and crops one side each cycle for about 4lbs/crop. Quit his annoying civil service job to be a grower full time and is happy as a pig in poo.

Sells it all to a dispensary in Ontario and they want lots more.
I'm gonna try it, I got the system awhile now, I'm pretty anal the way I do things so I didn't want to start until I figured it out, I'm gonna try when I harvest this grow I'm in now, thanks
I was pretty anal about it too but I got over that.
I started doing DWC in 2001. No internet and just an idea from a book I read that had some stuff about the floating gardens the Inca used to do and an article in High Times I think about if you could grow good pot in just nutrient water. I've tried all sorts of things since and it's become very easy for me to get a good crop every time without thinking about it much. Always in single RubberMaid tubs but I see RDWC in my future.
