DWC feeding plants

Obviously as the plant grows the water level in my 5 gallon bucket goes down. What do I do in this case? Top it up with nutrient water? Regular water? Change out the entire bucket every time? Does it make a difference based on whether it's in veg or flower?

All help is appreciated. THANKS!

I also have the same question, can someone provide a link with a good guide

I found it easy to just have a 5 gal bucket full of water with my PH and nutes already mixed to specs before topping my buckets off.At least you know it will be right or pretty dam close. Beats the hell out of adjusting ph and nutes in your bucket with the plants. I have a small pump that pumps it in.Simple.

I like to have them eat nutes and drink water at the same rate.

example:
1. water level goes down, ppm's go up = plants drinking more water than eating nutes. Add a lower ppm solution to top off.
2. water level goes down, ppm's go down = plants eating more nutes than drinking water. Add a higher ppm solution to top off.
3. Water level goes down, ppm's stay the same = plants drinking and eating at the same rate. Add same ppm solution to top off.

#3 is where I want to be.

I start with 5gal and when it gets down to 1-1 1\2 gal I replace it with fresh. This keeps the res consistent without adding more of what the plant doesn't need. I just replaced 3 buckets last night and all 3 of the old ones poured into one bucket was less than 4 gal. The roots act as wicks so the really is no need to keep it full.

Been using recir rezes for a few years

This last grow I decided to top off with pHed water ~ 60ppms CaMg + ~ 50ppms Himalayan salt solution

Also using it to flush Melanie

I replace whatever is left ~ 7 days in flower mode

Also using to foliar feed clones

Topping off is alot easier to do if you have a PPM meter. Sometimes your plant wont take up as much nutes as before or it might take up more, im hoping you have a ppm meter....... You dont want to wait to long to refill becasue if the roots have to stretch down to reach the water then it causes rope roots which slows the growth of plants. You dont really want to let it get down much past the net pots to prevent this from happening. Topping off is also a easier way to keep the ph balanced in my opinion, it also saves on nutrients when you just add a little bit here and there

Topping off leads to a res rich in salts and un needed elements. Letting the res go down let's roots grow fine, I've never had a rope problem. What could be easier? I start a res and over the next 10-14 days I check pH twice then I redo the res. No topping, no worrying about ppm, no taking lids off every day.

so will the amount of water i add to bucket get smaller and smaller as the roots get bigger? all that mass has to take up some space or am i wrong?