First Water Change - Question

[ChrisKSB]

I have a new/used 180 gallon tank and am ready to do my first water change. I was going to mix 50 gallons of water and do 25 gallons today and another 25 5 days from now. I will also be dosing 45ml of PraziPro during this change because my Tang seems to have something like Flukes or something.

Question is - can I just leave the extra 25 gallons in this bottom barrel shown below until next week, no heater or pump? It is not 'air tight' but the lid sits on pretty snug.

Would I be better off just mixing 25 gallons worth then start fresh with another 25 gallon batch later?

 

[Tahoe61]

You can leave it in the container until next week.

 

[Red_Beard]

It will be fine for a week. As long as it doesnt have any probiotics you can leave it much longer. I have had some sit for more than a month, no pump and it was fine. Now though i just leave a power head in it all the time. Mix 55 galons and use it over the course of a month or so and fill it up again when it gets to abt 5 gallons or so.