Is it normal for a guppies poo to be hanging out by about 5 mm!! Water parameters are all good, only thing that is slightly out is ph @7.5. Could this effect them.
Im feeding them King british tropical fish food flakes
What color is it? If it's the color of the food they've eaten, it's ok. If it's white or clear and stringy, then it may be a sign of intestinal parasites.