Does flourish excel drop the ph
I have a 55 gallon tank moderately planted, with rainbow fish. I just started the tank about 4 weeks ago. I noticed that I had a bloom of brown algae and I started dosing excel two weeks ago. My PH before dosing the Excel was 7.6 to 7.8. I dosed one Full daily for one week. I then did a 50% water change in added for capfuls. And then 1 to 2 capfuls thereafter for the past 2 to 3 days. Today I noticed that the fish were hovering at the bottom and we're not as active as they usually are. I tested the water parameters. Everything was normal meaning that the ammo was zero, nitrites were zero, and nitrates would between 10 and 20. I checked the pH and it was six!. I added several teaspoons of baking soda to my sump and the pH came up to 7.6 to 7.8. The fish are starting to swim around a bit more at this point.
I don't understand why the pH droped so much and I'm wondering if it was the Excel. Can anybody advise me on this point?