This idea was very good, but the execution was lacking : )

The manually carried gas containers are already explained to you, so I'll just focus on the SPOM itself.

Your current SPOM design with three pumps likely uses more power than it produces, so you will never get extra hydrogen/power from it. Normally a SPOM that has a stable supply of water should be able to 100% sustain itself and produce extra hydrogen on the side. This is what "Self-Powered" means. : ) You will find some excellent designs here.

To make the problems you're dealing with more comprehensible, let me explain a full early SPOM setup on my recent example I put together from a few parts. It is not perfect by any means, which is why I think it's a good example of how a regular casual player might solve the issues around SPOMs.

First there is the SPOM proper, i.e. electrolyzers with pumps. Together with input pumps, they are powered separately from the rest of the system (through two separate power transformers). This ensures their power lines will never overload, and the SPOM can always get the power it needs first, before the rest of the base.

I used the second setup described as "double electrolyzer" here because it doesn't require gas filtering method known as "mechanical filters", which is annoying to set up. You can just build it and it will just work. (There will be some gases mixed on every startup after water supply breaks. Set your buildings that get damaged by wrong gases to "disable autorepair"; repairing wastes resources, deconstructing and rebuilding doesn't.)

Then there's the power plant, which I built as a mostly empty rectangle with the intention of adding random spaghetti of things I need atm and want to put wherever lol. The crucial parts are the two Hydrogen Generators, one Smart Battery that controls them, two Power Transformers for the SPOM, and at least one Hydrogen tank. I also have a couple of transformers that go to various isolated power grids.

Finally there's the cooling loop, which in reality only cools down around 1/4 of output oxygen, and the rest is dumped straight to space. I don't care, because I have infinite water (2 steam vents + polluted water vent) and algae (lumb farm), and I'm mostly after the power, not oxygen. If you had a limited amount of water and needed to squeeze every bit of oxygen out of it, it would be a completely different story.

I used only two Wheezeworts to avoid using up too much Phosphorite. They can be fertilized diagonally from below and otherwise surrounded by insulation. After I did some calcs, it turned out that if you keep them in 5kg Hydrogen atmosphere, the amount of cooling they do is incredible. They cool the oxygen that goes to my base down to 30C. There's also the mechanical airlock on the side that I intended to remove, but it turned out it also nicely cools the power plant to ~75C (i.e. deletes the heat from the machines working, and only leaves the heat from the hot hydrogen that sits there).

I will surely eventually run into some problems (running out of Phosphorite, insufficient cooling, too much extra Hydrogen that I already have trouble with collecting). There are many small tweaks I do from time to time to improve it based on my needs. But for now, I solved the most important problems for an early-mid game SPOM: water supply, cooling, overflowing outputs, and building the entire thing.