How Often Do I Change My 5 gal Bucket dwc Flower Nutes

I am in my 2nd week of flowering going into third week and im wondering if im doing the recirculating process right, im changing out nutes for aggressive bloom (gh nutes + a few of their advanced nutes, check the chart if you have one) every friday, but plants are so big they eat up a gallon of water in about two days, i just top it off with ph'd water until the next friday. So heres my question, am i pushing to much nutes into my plants, should i do two weeks and keep topping off the water, or keep at one week?

I've got two flowering plants growing in a 6 gallon DWC, they drink about a gallon and a half each day. I've fucked off and let them run dry a couple times, they hate that. I let them drink until there is only a couple gallons left so the plant don't get thirsty and wilt. Then I'll top it off back to 6 gallons with PHd water mixed with my fertilizers per gallon recommendation. It seems to me that if they can handle the nutes, let them drink it up as fast as they can. I don't have much experience, this is just my first grow but other than letting them run dry a couple times my plants look like they are happy.
I do completely empty and wash out my res once a week. If I feel the sides and it's all slimey then I know it's time to wash it.

cool, thats what i have been doing. I know what you mean the slimy sides and bottom, sometimes even my air hoses are a little slimy, so i clean all that. Thanks for your opinion man, its greatly appreciated

I don't like the idea of feeding your plant at the beginning of the week and just topping off with PHd water for the remainder.
You want to give the ladies as much nutrients as they can handle. Not too much, not too little. Find that happy spot.
I top off every morning with water and add nutes if my PPMs dropped. Lets say yesterday morning it was 1000 ppms and the next its 900. I would adjust it to something above 1000. Lets say 1100 because shes taking up the nutes.
If your ph lowers and ppms raise you're nute levels are too high.

I don't know the book answer. But this is how I do it and my DWC plants show me their love and appreciation.
Best of luck

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damn i need a ppm meter bad i have yet to get one