Eheim pickup 60 or 160?

[Fish]

Ok cheers, I’ll order some later. It’s definitely not 25mm but there is a lot of spare room inside the filter. I presume if I add it while cycling I’d keep the premade carbon in for a while to keep the bacteria going?

[Martinspuddle]

I presume if I add it while cycling I’d keep the premade carbon in for a while to keep the bacteria going?

I wouldn't disturb the filter until a month after aquarium cycled.