Okay first off, is your tank cycled or uncycled? Either way, you will definitely want to be cleaning it more than once a week.
Also, refrain feeding freeze-dried foods as anything more than a treat. They are notorious for causing constipation. You can even feed your betta diffeent brands of pellets for variety... they all have slightly different ingredients. Half or a quarter of a defrosted pea makes a good treat, and only a treat. As in once a week at most. Bettas are not vegan!
I also strongly suggest you consider feeding frozen or live. They are far easier than you might think, ultra tasty and ultra nutritious. They make an excellent supplement a few times a week, and last forever.