New 40gal tank question

[BaraBlu]

So atm I have a 15gal that I make saltwater for with with my new addition of a 40. I have the sand and rocks to put in it with the sump pump I need to setup still. I'm wondering about adding the water in slowly since I can only make 5 gal buckets at a time and would take me some time to fill it up. Was wondering if adding it in one at a time slowly would not work or any work around for this? I would rather not buy a large drum to fill it up so I was thinking that I'd just mix 5g at a time and add it til I hit 40 and add the ATO once it's done. I also don't want to kill the bacteria in the sand with the unstable waters since I would be doing one bucket every 4-5 hrs with to water being made then mixed. If anyone has a simpler option that would be great because I would like to avoid buying water when I alr have the instruments for it, ty

 

[NeedAReef]

you should be fine bit it would be a while before you have enough for the overflow etc. so make sure you put a powerhead or something in the 40 to keep stirring the pot so to speak.