Preventing tile grout from getting dirty

jonny2510

We cleaned our tiles a few weeks ago (3 at most) using the MSE OS recommended bleach with bicarbonate of soda method, which worked a treat, and left our grout nice and white.

However, already, the black mould/growth is back (almost to the point where it was before we did our 'deep clean').

Can anyone offer any hints or tips to prevent the grout from going mouldy/dirty again so quickly?

• The shower is a separate cubicle.
• We have an extractor on (albeit 2m away from the shower), and window open (next to shower) during showering, and usually for around 30 mins after.
• Windows vents are typically left open all day.
• We leave the shower cubicle door open after showering to let the steam out.

Is there anything else we can do/apply, to prevent this from occuring so quickly?