Poor top layer quality

Hello,
I'm quite new to 3D printing and lately (all the time actually) I've been struggling with bad look of top layers of all my PLA prints (I print only with PLA). As you can see in the pictures, there are small "pillows" where there is no infill beneath the top layer. It doesn't matter how much infill percent I will set, this always happens. The bottom layer and the walls are nearly perfect, so I have no idea what may be the problem. Currently Im printing at 190C (earlier at 210C), 90% flow rate, 43-50mm/s infill speed in Cura on Vertex k8400. Bottom and top layers are 0.3mm thick, and im only printing at 0.1 resolution. The fan is always turned on max speed. Im a bit scared to mess with the settings more, so im posting this here. Thanks for the help in advance.

More top layers for a better finish.
.1mm layers with a .3mm top is only 3 layers solid.
While this normally is fine sometimes you might have to do 4-5 instead.

Ok, i will try that, but is there another solution? I feel like adding more layers should be a temporary method

Printing at lower Temps works well for me. I've been printing at 180 recently, though I haven't checked what my hot end is actually running at so it may be hotter than that. Cooler Temps means more solid flow and better bridging.that being said, at 20% to 30% infill with a .4mm nozzle works great with three layers of solid top layer. As long as your layers stick cooler Temps are better in my experience.

You look like you need a layer fan. The hot air inside of the pockets made by the infill puffs up the warm layers if they aren't cooled quickly.
On the Orange Whistler (black plastic), there looks to be over-extrusion. try changing the set diameter down my 0.08mm.

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Master Tinkerer

When printing with the 0.3mm nozzle and onyl a slight infill I realised that the first top solid infill is more like bridging than normal printing.
With the 0.7mm nozzle there simply is no such problem as the layers are much thicker.
Just to get a solid and clean top surface I need at least 5 solid layers to get a smooth finnish, if the infill is below 25% I need up to 7 layers.
I does help a lot if you slow the top layers down, either in the gcode or manually during the prints.
Once it looks solid the speed can go up again.
IMHO fan cooling has little to no effect on this as there are simple physics involved.
With a fine nozzle and a weak infill you simply need a few layers to get a solid base to finnish off.

Quote
Downunder35m
With a fine nozzle and a weak infill you simply need a few layers to get a solid base to finish off.

I agree. You cant just leave your print settings alone and hope everything will come out great. Every model and every print needs a little tweak of the settings to work better depending on the situation.

I adjusted the settings so the top layer is now 0.5 mm thick, and it made a huge diffrence. Its not yet what im hoping to achieve, but its way better than before, thanks to everyone for their pieces of advice