Single reservoir mixing station

[Diman1974]

I am a new reefer switching from the freshwater side. I just started my first 20 gallons AIO and doing a research to convert one of my larger tanks to saltwater (125 gallons).
Mixing 3-4 gallons for my current tank is not a big deal but I will need a proper salt mixing setup for a large tank. Most of the designs here and on youtube use double-bin setup (RODI and mixed) but I am planning to build a single reservoir station from 55 gallon open-top water drum from Uline.
Why is single reservoir method so unpopular? What am I missing? Attached is my planning sketch. It is ugly but self-explanatory. Please provide your feedback.

 

[ReefStable]

I mean, it looks good to me. Most likely, the reason double is more popular is because larger tanks are more popular for having a mixing station. I can't see any reason why you can't have just 1.

 

[Sirlagzalott]

Having a separate RO/DI tank also gives you the benefit of having spare RO/DI water on hand if you need for top off, etc.

 

[EricR]

It's more convenient to have freshwater and saltwater separate,,, so you can refill your ATO (auto top off) container and/or do water changes without having to coordinate when you have either fresh or salt in a single storage container.

Beyond that, your idea seems fine,,, but I feel like that's a pretty big concern (to me, anyway).

 

[Diman1974]

It's more convenient to have freshwater and saltwater separate,,, so you can refill your ATO (auto top off) container and/or do water changes without having to coordinate when you have either fresh or salt in a single storage container.

Beyond that, your idea seems fine,,, but I feel like that's a pretty big concern (to me, anyway).

you are right about the coordination part. I came up with a simple solution. I will be using a whiteboard for reminders/notes

 

[SpyC]

you are right about the coordination part. I came up with a simple solution. I will be using a whiteboard for reminders/notes

I think the simple solution creates more problems.

 

[EricR]

you are right about the coordination part. I came up with a simple solution. I will be using a whiteboard for reminders/notes

Even beyond that coordination, there's always a chance for a sudden, unexpected need for one or the other (RO/DI vs saltwater).

 

[Diman1974]

Even beyond that coordination, there's always a chance for a sudden, unexpected need for one or the other (RO/DI vs saltwater).

I have a 20 gallons Brute that I will connect to the RODI system with a float valve.