Dose the clean tank solution work or should I use a product like digest it.
First, it DOES make a difference if you travel with your camper or if you are sitting stationary for a length of time. There ARE different methods for cleaning the tanks.
If your camper is constantly "mobile", then the easiest way to keep (all) the tanks clean is to dump the tanks, then add a few gallons of water back into each tank. After that, drive to your next destination spot. The sloshing of the water in the tank will be the best thing you can do to keep it clean. If you a 1/4 cup of Dawn dishwashing liquid, or a cap full or two of Tide dishwashing detergent, and let that slosh around, you tanks will be cleaned out. When you reach your destination, you dump the tanks again, then use them as normal.
After the very first use, the tanks will NEVER be "new" clean again. All you can do is keep it as clean as possible.
You can also do some creative things, like back-flushing your black tank using your grey water tank. There is an entire process for this, but it's very easy to do, and you don't use any extra water to do it.
Some folks use toilet wands attached to garden hoses and shove them down the toilet bowl hole. This works well too .... especially if sitting stationary.
Another trick you can do is, when you wash dishes, use a tub in your kitchen sink and keep the dish washing soap water and pour it down the toilet. The dishwashing soap is always a good thing for the black tank, no matter how much or how little you use.
I personally do not use any type of chemicals and we do not use toilet paper at all.
WHAT??? you say???? It's a long story, but I installed a bidet in our camper and we don't need TP any more.
Second, I back flush from the grey tank to the black tank and then dump the black tank EVERY time I dump tanks.
We also have a washing machine and dryer in our camper and the washing machine water will get back-flushed into the black tank (Tide) and helps clean the black tank without having to do anything else, except dump tanks.
Last, I use this the least, my camper is installed with a black tank flusher. I use it occasionally, but I've learned that the back-flushing works a whole lot better and it does not use additional water.
So, there are alternative ways to clean your tanks without using high costly RV chemicals and RV tank chemical. They are not needed! You already have everything you need.
Here's the rule .... anything you can wash clothing with is OK to use to clean your black tank out with. Anything you washing dishes with is also OK to use in your black tank to help clean it out. More is not needed!
If you don't do the back-flush method, then you need to make sure you fill your black tank before dumping. If you are cleaning the tank, (and not driving), then fill the tank a second time with laundry or dishwashing products and then dump.
Avoid bleach in the tanks. However, we do use bleach in our washing machine and after 4 years, we've not had any ill effects yet.