Mars and 115 mm - which eyepieces? Today I could roughly see Saturn with ring structure for the first time with my Seben 114-1000 telescope.

Then later I was dealing with Mars and found out that I must do something wrong, as with no eyepiece I could really see this planet closer.

So, whether I take 20, 12.5, or 6 mm eyepieces, the size as I set sharp focus remains a small light orange circle of solid uniform colour.  The app sky view shows for today 64% clear view, maybe an explanation why I can't see more details.

But is this possible to see Mars filling in the view field? And why there is no recognizable difference between 20 and 6 mm - do I need them in combination with something else? 
Here it says, even the polar caps of Mars should be recognizable with this telescope model scale.

UPD

So far, it looks like that with up to 6 mm I can zoom in fairly well to such details as:


large moon craters
Jupiter (seen as small white illuminated blob) with the Galilean moons (seen as  stars)
Solid white-coloured Saturn with its ring and some space between planet and ring visible


Mars keeps being small to medium yellow-orange disk of solid color.

Using 4 mm gives little bit more zoom but less detail.

However, I can see with 6 mm that Moon contours are slightly jittering, maybe through light refraction in the night air (all observation done from the ground on a field). The temperature in the night has been 21°C.
Mars is currently experiencing a global dust storm. There are virtually no features visible.

Otherwise, some dark markings and the polar cap would be visible when conditions are favorable (meaning when it is close to us as it is now.)