Cheers!will do water changes as well tomorrow.
Will he cloudiness be an issue when the fish are in the tank when cleaning the bottom?

Completely gutted! The sand just won't settle and there was black residue forming at the top, it's anything but clean.
I took out the filter and looked at it, completely stuffed with sand and clogged.
I have now dumped out all the sand and rinsed the tank out.
Quite annoyed as I've now lost two weeks of the new filter media that's been building slowly.
Going to put in fine gravel today, hopefully it's more manageable.