Happy Campers Organic RV Holding Tank Treatment
There are huge opinions of what to use to properly maintain your blackwater tanks (as well as your gray water tank). We have tried most of them. Some try to kill it – Formaldehyde concept. Others try to use bacteria to eat it up.

Our findings:

Most of them don’t work.

This is the first one that seems to work very well for us

Happy Campers Organic RV Holding Tank Treatment

Expensive up front purchase but it last a LONG time. Probably cheaper than all the other ones out there.

We put 1 scoop in the Blackwater tank and 1 scoop in the grey tank and it takes it from there.

Wrote an article about it here