Recommend me some flux?

[paulca]

I have still got the CircuitWorks flux pen I got 8 years ago.  But it's tip is getting pretty manky and dirty and ... shorter.

Watching YouTube videos I like the looks of liquid or gel fluxes they squirt out with a syringe.

When I search for flux I have no idea what to select on even. 

Rosin?  Activated or not?  Which do I want and why?  Im assuming activated rosin?
Clean vs. No clean.  Stuff I have is No clean, which I beleive means if you are lazy and dont clean it off it doesn't eat your board or components. 
Water soluable?  What trade offs do you make here?

I think even if I answer those questions Digikey still gives me 100+ options to pick from.

Purpose.  Mostly going to use flux when I am reworking SMD components, hot air or iron.

I just sent a digikey order and currently the "Free shipping band" is high, so Im open to both "Proper supplier" options and "Aliexpress worth a punt" recommendations.

[Monkeh]

Water soluble generally must be washed off with water, so if you're unwilling or due to components unable to put the board through a warm ultrasonic cleaner.. or dishwasher, that'd not be the choice for you.

With gel fluxes no-clean isn't no-clean in my experience, the whole point is they stick around, so you'll be cleaning.

Last few years I've been happily using Warton's Nexus 'Rework Gel', you can get it from CPC. It's not the cheapest stuff around but it flows well, cleans up nicely, and gives me good results. Just.. bin the solder wire it comes with.

[grx]

After looking at videos to make my own mind I settled on the Mechanic SD360. It stays transparent, does not smell bad, does not smoke a lot, does not go away too much with hot air, and really helps the solder to flow.

it's a no clean flux, which means you need some wipes and IPA to remove it , because it is very sticky when cold (which is very good for flux purposes)!

[thm_w]

https://www.eevblog.com/forum/other-blog-specific/nanofix-youtube-flux-comparison/

You want no clean, not water soluble as its generally more active.