I use smart captcha. It's question based and harder for them to crack, esp when you use math questions

I use user approve, I then check the emails using stopforumspam if they are in there I don't approve them, By googling the email if it is on any spam databases it will pick them up,

Use Watchdog Plugin from the Store, and also make sure you have cloudfare free edition...its help

Checking IP is not an option since they will use new one! I am scared messing with htaccess. Guess there is no way to get rid of them for good just have to deal with it and eliminate one at the time. Thanks for tips guys.

In a few days there will be something available in store to help you, i cannot say what it is right now as i do not want to spam or publicly release the news yet.  But give it to the weekend and see please.  

RE: watchdog  - now this may have changed since i used it years ago but be careful using watchdog, this has been my experience with it. (this was years ago)

First it slows down your site dramatically. 

Second the way they have their queries written if you have to restore the db for some reason then the process will stall on you because watchdog is a incredibly HUGE table data wise and you will need to cut that whole process up into chunks on a shared server.  

I think when i did it i had to cut it up into 3 or 4 sql files and run them individually to get it back imported. If i tried to run it all at once the import would stall because it was just too large and the sql statements encompassed to many inserts per statement. 

So if it is the same just be aware... 

Awesome keep me posted buddy thanks so much! I think enabling some like forums have where you have a certain amount of time between posts should slow and block them! If the boot wants to post too fast show it a message first like "you are trying to post too fast please wait x seconds" or  chaptcha!

OK markus its available now check out the store, surprise :)  

Dave baby can I borrow your brain man you are smart! Gonna test this baby out soon!

Thanks Marcus,  

surprise again!!   enjoy your new tool :)   let me know how it goes.   

Just like to say this plugin of Daves is perfect for keeping the bots out, the bot script developers struggle to get around this type of captcha.... I've been using a similar one on my site for years and I have a zero bot problem.
I'm now using daves and it's just as good if not better as it offers more options :)