Connect with a pair of RCA to 1/4-inch TS cables or the pair of RCA to XLR(M) cables in your link. The RCA output signal is unbalanced, but with most installations using typical length cables, and with the monitors powered from the same power strip as the source device (your Traktor Kontrol Z1 mixer/interface), there will be little likelihood of a ground loop being produced.
If you do have any hum/buzz/noise issues when the monitors are connected and there is no audio output present, then a galvanically-isolated unbalanced to balanced connection is needed. The mentioned Rolls DB-24 is isolated and will work or there are many other similar transformer-isolated devices made by Whirlwind, Rane, RDL and others. The more expensive devices often use better quality transformers which will have less affect on your audio.
I'd recommend you try the simple, direct RCA/XLR or RCA/TS unbalanced connection first. If you have no hum, fine. If you do have hum or noise, then use an isolated transformer line-level converter to break the ground loop and balance the output. Be careful not to use a DI designed for mic-level inputs. Many DI's use a transformer, but also a 15, 20 or 30 dB attenuator to reduce line-level signals to a safe level for a mic inputs. That won't work to drive your active monitors. If the DI specifies 'works with mic inputs' or it specifies using a '12:1 or 10:1 transformer' it's wrong for your application. It should use a 1:1 or 1:2 transformer and not drop the signal level. Some actually can boost the signal level from the typical -10dBV RCA 'consumer-level' to the +4dBu pro line level common for XLR line inputs.
There are many types of 'DI's available having different input and output impedances, and having different amounts of signal level change. Most DIs with XLR outputs are designed for use with mic inputs, not monitor line-level inputs, so be sure you know what you're getting.