So needless to say being a newbie got the best of me and after having my tank set up since January, I think I either killed my cycle or never fully established one and my fish started to get sick and started dying off. So now I have a quarantine tank with what fish and fry are left and then my 20 gall setup empty. So how do I start my 20gall tank over the right way??? How do I clean it now? Do i have to buy all new sand? And is it ok to keep the remaining fish in the quarantine tank until the 20gal is cycled properly?