https://www.calvetsupply.com/aquarium-doxycycline-100mg-30-capsules.html
Ivermectin builds up in your system which is the reason for that first double dose.
Treatment is 18-24mg or 0.4mg/kg of body weight once a day for five days according to FLCCC.
Your link goes to doxycycline, not ivermectin.