There are several filters that you can use to filter out your grid results. One of the most used filters is hiding and showing the accounts you visited using Circleboom within an exact time span.
When you start following users, it will take a few days for them to realize someone followed them. We’re applying "Hide who I visited within X day(s) on Circleboom" by default. You can change our default of “30 days” if you want, but our suggestion is to set it no less than seven days.
The same filter becomes "Hide who I visited within X day(s) on Circleboom" when you visit "Circle tool." By using this filter, you can easily filter out the people you have already visited. So, you don't have to think about if you're trying to follow the same guys you followed and dropped before. We’re applying this filter by default. You can change our default of “10 days” if you want, but our suggestion is to set it no less than seven days.
Due to Twitter’s strict policies about aggressive or spammy follow churns, we’re constantly tuning our algorithms to make sure that our users don’t get marked by Twitter for their behaviors and helping them don't get their accounts locked or suspended eventually. Here is an official announcement about policy clarification which clearly says following and unfollowing immediately after 24h would be considered as aggressive following.
"Automated follow-back monitoring, and other forms of follower churning, are not permitted. For example, following 100 users, waiting 24 hours, then unfollowing the users who haven’t followed you back would be considered aggressive following. Repeatedly following and unfollowing a user is a form of spammy behavior, and is never allowed. Following an account is a way to express your interest in them, not a way to try to manipulate another user into following you back.” https://twittercommunity.com/t/policy-clarification-aggressive-following-and-inorganic-following-behavior/92769