Sand To Gravel

[carpking]

Hi all

I've just had a tank go down so I'm going to re build but I'm going back to gravel from sand my question
Is can you use a under gravel filter as well as a external filter and is it a good idea?

My tank is 180l

 

[techen]

Dont use under gravel filters on a huge tank like that, You won't really benefit much. Why are you changing from sand?

 

[carpking]

Hi

I'm changing from sand because I have just loss most of my fish to a worm issue so I will be replacing the sand as I don't want them to come so I'm thinking I wil go back to natural gravel as it looks better and hides the poo better, I know it's still the and always clean my tank weekly but in between cleans gravel looks less covered in s?!"