Question Water Cooling Flow Effect with CPU Integration

[Masohas]

I have a situation with my water cooling system – there's a flow effect, and I’m wondering if it’s safe for the computer. I can constantly hear bubbling, probably due to a lack of coolant. Can I add a different coolant, or how does this work? I bought the computer used and have no idea what’s already in the system.

I should note that when I bought it, I don’t recall hearing any bubbling sounds.

I’m completely new to water cooling, like the liquid in the reservoir – it’s my first time dealing with it

https://imgur.com/a/bO2Du9R