Blackouts are free and are pretty effective. That’s why so many people on this forum recommend them. The issue people have is they rush the blackout. Everything looks good so they run the lights like normal, feed like normal, and what little dinos are left in the system come right back.
The thing about this hobby is that there are so many bitter people. Their answer is the only answer, the equipment they buy is the only equipment that works, they had it rough so you have to have it rough to...
Time is an issue here. There are approaches that are free, that won’t harm your tank, that you can experiment with (back off or continue). Inaction and waiting is gonna do more harm than trying. To each their own
They are free, but if you go to the threads here, the ones where each type of dinos are id and treatment for each is outlined, they do NOT work for most dinos.