HELP...I got a 2 Gal. Tank to use as a Hospital tank but right now had to put Mama Guppy & her Female offspring in it to avoid any more fry than I already have. I just changed 1/2 the water last night as the Nitrate level was as high as it could go. But now, it's STILL High, should I add a Tablesp. of Aqu.Salt ??? How much Salt is tolerated by Guppies ??? Any other suggestions ??? THANKS !!!