It's also helpful if, like me, you have zillions of snails and, like me, can't bear the thought of leaving any in the redundant gravel. You can have a sort through the gravel while it's in the pan. Panning for snails is not quite as profitable as panning for gold though!
Thanks for the advice folks i'll be doing it this weekend all being well and if not this weekend the weekend after i'll keep you all posted and throw some more pictures up as well when i've done it for the minute some of my pics are up in the gallery!
Think carefully what you are going to do with the filter - I'm not sure you can run a big external in a RU box without creating a tsunami but it may be possible if you can alter the flow rate? Make sure you get the coral sand washed before you start on anything else.
took all your advice on board and decided last night to do a substrate change, i bought a container from B&Q big enough to house my heater and filter borrowed a couple of buckets and transfered all the fish and water then used the net and the shovel (GREAT IDEA BY THE WAY THANKS) and got rid of all the gravel.
I put back all the slate then added the coral sand and left it a couple of hours before rehousing them back into the tack i tried my best to put everything back to where it was and the julies and ocellatus seem happier than before i've posted some pics in the gallery.
again thanks very much for the advice and i have to admit it does look better oh and nitrites are back to normal now