Septic root problem

We have a 750 gallon septic tank....having root problems.....is Ridex good eneough. Wondering how much to use and how often to use,thank you.

I do not know for sure, but I think there is no additive that will get rid of an existing root problem even though I have heard copper sulfate can keep them away.

Are the roots actually all the way into your tank or are they still only out in the drain field?

Ridex or none of the other septic system bacteria "additives" will help your septic system OR get rid of roots. They're all a waste of money.
A cup or two of copper sulphate crystals flushed down a toilet about three times a year will keep the hairlike rootballs out of your system.
However, if you have a sectional sewer line (cast iron, etc.) - instead of a solid "glued" (actually chemically "welded") PVC white plastic or ABS black plastic sewer line - that will not allow any roots in, you may need to have the line "roto-rootered". If you do that, it will only last a couple of years at most.
The only permanent solution to roots is "solid" plastic line that doesn't allow them to get in.
Good Luck!
Mike