I'm not so convinced that any flusher is all that worth it..... although I would like to have a bypass line somehow to fill my tank for flushing.....
but IF i were every going to do what you are planning, I'm not sure I would use silicone caulk. I really don't like that stuff. it never sticks where I want it and it does stick where I don't want it. I find that it's generally a very poor sealant, with much better options on the market.
We used to use bulkhead fittings on HDPE industrial tanks all the time when I was in the paper chemistry business. No sealant required, only a good thick gasket.... and we were dealing with far great head pressures and all sorts of chemicals that are far harder to deal with than dirty water....
...in my case the better approach i think might be to plumb it into the lavatory drain pipe so that I don't have to penetrate the tank. I would use mine, not for trying to jet the tank clean, but for what I just did this weekend... had far too little liquid in my tank for a proper dump, so I filled it up most of the way with a hose, so that I could then dump the tank. I could more easily accomplish the same thing with one of those valtera connections with hose adapter. I'm convinced that is all that is needed.
__________________
|