Indoor cactus help

[Cheesenacho123]

What type of cactus is and how should I look after it? I’ve been giving it water once a week or when it looks bone dry. Mainly from the bottom. God knows if this is right or not :/

Sorry no idea what kind of cactus it is and hopefully somebody who does will be along shortly :)

But I've had my cactus for almost 3 years now in a similar set up and just water it from the bottom every few days or so and keep it on the window sill to catch the sun.

Is it by any chance a grafted cacti? Google isn’t a great help to be honest

As the resident cactus expert, I'll try to help . Yes, it is grafted - the stock underneath is Selenicereus grandiflorus, much used by continental nurseries in Belgium and Holland etc to speed growth.
The scion on top looks like Notocactus scopa (which is easy enough to grow on its own roots).
The stock is a tropical rainforest climbing cactus, and is thirstier than desert dwelling cacti, so watering once a week should be fine. It is also prone to rotting if kept too cold in winter, but should be fine on your windowsill.

Brill thank you! So far it’s survived one winter on the windowsill down to around 15.c and been fine so I’m happy I haven’t killed it yet. Can you get special soils to repot it in? As I’m going to put in a bigger pot due to the roots coming out the bottom

There are packaged cactus composts available, but they aren't necessary really. As the stock is a rain forest plant, it doesn't need the sharp drainage of desert cacti. You can use ordinary potting compost with a little grit or perlite mixed in. I bet it's potted in some sort of peat or coir mix, they usually are. And don't over-pot it, better to be under potted than over potted.

Ok thank you :)