@essadis420 Welcome to AFN. Pro Mix HP is primarily peat so you want to PH at 6.3 going in. Your starting water of 150 PPM will be about 50 PPM of calcium so you should not need to add any. You also do not need to dilute it.
It would be good to look at your water report to see how much calcium and magnesium you have in the water? Sanitation is also a question; looking for ammonia in the sanitizer section.
Water report avg. 52 mg/l calcium, 16.7mg/l magnesium, ammonia <0.05 that’s if I’m reading the report right lol
So I should keep my water closer to 6.3 when I feed them tonight instead of 5.8?