Lawn Care Advice

Hi all,

New to this sub and to lawn care in general.

Located in coastal Victoria, Australia where it is summer for context.

I have the lawn in the images above. I've been told it is couch grass?

I have also got the weeds that are in the images growing.

I would like to fix the weeds as the rest of the lawn looks fantastic.

I bought the product in the images but have since read differing reviews and scared as the product mentioned the lawn will 'turn black' for a while.

Should I use this product, or can anyone recommend a better weed and feed regime.

Thanks!!