I have 2Brown Discus in a 300 litre tank .they keep on breeding but the eggs are laid grey colour.why are the eggs grey.My male constantly ,trying to fertilize the eggs ,after a few days they turn white so then I remove them.My Ph,is 6.5.I have soft water,and do 20 percent water changes 3times a week.Temperature of tank is 82. Other breeders in my area have no problem with breeding Discus in my area using normal tap water.