Supercritical ocean planets?

There may be many planets covered by deep oceans through the universe. But what if some of them were at a bondaury between rocky and gas planet? I mean, if the planet has, say, more than 25000 air pressure and temperature above, say, 750 °C, such ocean should not be liquid, but at a supercritical state. In this case, such worlds would have supercritical ocean? Let's say this ocean is 100 km deep. Would it be possible to see the surface through such supercritical ocean? In this case a rocky mantle beneath the supercritical ocean. Would this ocean look like a liquid or all we would see only a hazy environment? Some say that Venus may possess a supercritical CO2 ocean. Is that true? If it is, it would be possible to see the surface through that deep ocean if Venus had not so opaque clouds? One more thing. Due to the high temperature, should this supercritical ocean glow red?

According to http://www.trimen.pl/witek/calculators/wrzenie.html, if the surface pressure was 25000 atm, water would boil at 1112°C. In a planet I created using Space Engine, it had air pressure of 21750 atm, so water would boil at 1062°C.

Supercritical water, obviously. The planet in question has 10 earth mass.