I just finished a 5-day water yesterday, lol!
Harmalas wouldn't have any metabolic effect on your fast-- so you're fine there. But be careful with your dosing, because your hormonal balance, metabolic process, and general internal chemistry fluctuates by fasting-- for example, as you experience the die-off of some gut flora you will be very tired and sometimes will feel shitty.
I would consider lowering your harmalas a little during the second half maybe, as you may experience a different degree of effect that when your system is divided by the processing of food 24 hours a day.
This usually starts on late day 2 or 3. This time for me it was all of day 3 that I was tired, but this overall fast was much easier than last year's. I don't know how harmalas would influence that feeling.
I do take vitamins C, Magnesium Glycinate, and a whole-food multi, and salt/electrolyte solution throughout my fast with my water, and bentonite clay/citrus pectin (at least 1.5 hours away from any vitamins/minerals) first and last thing to help bind toxins and help clean the house.
And remember-- the reintroduction of food (AKA re-feeding) is as important to your fast as the fast itself-- divide total fast days by 2 and those are the days at the end that you should just introduce liquids (like clear vegetable or bone broth, low sugar kombucha, unsweetened coconut milk, and other liquids that aren't all sugar like fruit)
The next day you can do soups that aren't too solid, things that are soft like well-steamed vegetables and things. Fermented foods are excellent during this whole time to help re-populate your gut with good flora following the purge!
Then you should be good to ease back in to the regular stuff you want
This isn't medical advice mind you-- just my opinion from my fasting experience