Need help with diy 2 part. Also has anyone had success with this?

[Major nc]

Woah A B C premix are dirt cheap compared to what Ive been using. $20 less per bottle and almost twice the volume. Ill be trying this out next month when I run out. Im guessing there's gotta be something missing to justify this price difference. I noticed brightwell had a few extra ingredients. Strontium chloride, borate salts, magnesium chloride and magnesium sulfate. Can anyone recommend anything else to add with premix A B C? I've done the 15-20 water changes for months and found it harder to keep my system stable and corals happy. But thanks for the advice Oversized skimmer 180-200 gallon, live rock and chaeto are doing well so far. Aqau forest minerals were mentioned.