right it is a 18gallon tank and is aprox 5wks old water is a whitish colour just done a water test with a tetra test 5 in 1 test strip and results are nitrates between 0 and ten, genral hardness 10, carbonate hardness 15, ph reading 8, i have 3 angel fish, 1 guarmi, 2 guppies, 1 tiny cat fish, a...