Uncolonizable planet?

[deMangler]

As a human player. There is a planet I was wanting to colonise. An ocean world at 44% quality. It has a couple of potential colony bonuses from resources and shows colony suitability as 0. It does not show on my new colonies list, or have an option to colonise it using the other UI methods.
I have colonised other ocean worlds. Some worlds show as colonisable that are further from my area than this one. I don't see any reason this planet is different.
What am I missing?

Thanks.

[WiZz]

You can set any desired suitability. Game manual, page 35.

[deMangler]

You can set any desired suitability. Game manual, page 35.

Thanks, that made me think about it more.
I am playing on full manual, it says that applies to automatic stuff, suggestions and so-on. In any case, you can't set suitability to zero, which this planet is, even though it has 44% quality. Maybe it just needs greater research, although I can't see an indication of this.
I am researching even better ocean colonization so I will update if that makes a difference when it finishes. Although according to the text that only affects quality threshold, and it is already 44%

[WiZz]

Forget about quality, only suitability counts. Also look into planet tooltip. In some cases it shows 0, but if you check it says -50 for example.
Look.
I can colonize

1.jpg (69.3 KiB) Viewed 557 times

I can't colonize

2.jpg (73.67 KiB) Viewed 557 times

[deMangler]

Thanks for the clarification.
The planet did become colonizable after Improved Water Colonization research it went to +4, even though in the research text it only mentions quality and not suitability.
Lots to learn.