I am not sure, I never swapped a tank, even at the small size. 
I am expecting a little mess and going to put down a towel and see what happens.
There is a drain/fill pump and hose and all that, I never used it though either with this. The pump is not installed yet, sitting in the front.
I’m anxious to see how it goes with 2 plants side by side in there! 
Post some pictures anxious to see an alternative
I will. This is all new, I am just scrambling to do something.
I think only growing 1 is best, but I have 3 I need to do something with, so 2 it is I think.
I swapped out the container today and it was super easy and even faster than a drain and fill.
I don’t think you can do this once it gets bigger, but right now, fast and simple.
I do something similar by taking my homemade reservoir out of the tent and dumping it to change it when the plant is still small.
Once the plant gets bigger and has more roots and is drinking faster you’ll find it is no longer necessary to change the water so much as just add more to it more frequently. 
I was looking into the cash crop 7 and the other one from dealerz that grows 4 plants. Curious how it works so keep us posted.
Can you post more pictures of the unit like what light it uses?
I will put up some more pictures later, just getting going.
I think there are some things to keep in mind about other boxes and I am trying to help others as this is what I been seeing. This is not for everyone, see below.
We are used to fancy fully automated boxes, this might look a lot different as everything is right there in the open and more “hands on made” like something one of us might do. That is what I really like after going thru many problems in the other box. Unscrew this to get this off so you can reach that, then run this wire all the up the side to the top and then… No, it is all right there.
Another thing about different boxes, is the “grow philosophy” I guess is how you say it? This is a COMPLETLY different way than what the other box uses on how to do things. This uses the more “semi hardcore way???” of use all “Advanced Nutrients PH balanced stuff” and don’t worry about much of anything else, even checking the ph. Some will love this, others will hate it as they want to control it all.
FOR SOME ON THE WALL ABOUT THESE: If your someone who, not knocking in any way just saying, feels they need a water chiller, add humidifiers. dehumidifiers, check ph 10x a day, worry about water temps and humidity and all that. You will not be happy with this, as you just about do nothing, water change 1x a week add a tablespoon of 3 different AN nutes and that is it.
FWIW, this is exactly the way I always did things, added all AN nutes and worry about nothing else, so this is perfect for me, maybe not for you.
I used the same timer in this pic and almost lost my crop several times!
It malfunctioned on me a couple times so it would be smart to keep a spare of some type incase you wake up to a system that never shuts off or on! 
OK thanks. I do have some normal wall timers around somewhere. I can dig one up just in case.
The only good thing is, if it died, the fans would stop too and these are semi loud, so you would 100% notice the silence. 
That is about my only semi negative with this, the fans run 100% full speed all the time and are loudish, not super super loud drowning out the TV, but enough you would notice if they were off and your in the room or close enough.
Hows your new box working for you?
Sorry I have been so busy. Everything is going good, I really did not do anything yet except move them from the other box. Today is the water change and I am going to make some tweaks I thought of for the drain and fill. I cut the 2 hoses from the other box and going to try to do something as the hose with the CC7 is thicker and stiffer.
The only suggestion I might tell others is, don’t try to grow 2 in this. Stick with one as one of mine is super bushy and I have to trim it up or it will hurt the other one.
FWIW, From 3, after today I will be down to 1 I hope.
Glad to hear it keep us updated
Thanks for the update as I will try something in a few months. Trying to figure it out and definitely would like your input as you grow with this
Did you consider the super closet when you were looking?
Hey sorry for not being around, I enjoyed my time dabbling with all this, but after the major loss with 3 boxes, I got rid of 2 and the 3rd is this weekend. I give up and will just buy at the dispensaries after the grow in the CC7. It might be some time before I am back again.
The CC7 is a very nice box, no issues at all except the fans run 100% when on, you can probably get some kind of adjustable controller on Amazon. After the initial setup with the lights and setting the timers, it is just change the water once a week and add 1 tablespoon from 3 bottles.
The drain and fill, I tweaked myself and drilled 2 holes in the lid so I can leave the drain pump always connected. Their way was to use the same pump for drain and fill. So you would always have to swap it out. I also added a 2nd small pump for $5 and that is the fill pump and goes in the bucket. So now the drain and fill is more like the other box. Plug in the drain pump, then unplug and plug in the fill pump. A little more manual but easy enough.
how did you lose your grows? I just bought the growzilla after reading reviews and seeing it was high times top rated grow box.
That was meant to say lose your grows. What went wrong?