Toilet buildup and slow/no flush

[Adkroot]

Toilet suddenly began flushing poorly and then not at all. No clog after snaking, and bucket of water poured in flushed it fine.
A couple months ago I cleaned out quite a bit of dark grey brittle buildup that had formed in the large siphon jet opposite the bowl exit drain and that corrected the issue. It started again, and this time I was able to flake off a large piece that had formed in the exit drain at the bowl, but I’m still not getting much of a flush. I’m thinking there’s more that’s out of reach.
But my question is this: I have relatively low ph well water (6.24) so it seems unlikely that it would be limescale, right? My hardness is 17 mg/l so there doesn’t seem to be a high level of minerals (iron is .030 mg/l), although I didn’t test for magnesium.
Any ideas what might be causing this buildup? Thanks, Daniel

 

[Breplum]

The trapway and low points of the bowl the toilet build up mineral deposits from urine and even average water. That rough trapway surface contributes to WCs perform worse and worse over time.
You experienced the exposed places you can see, but the hidden path is impossible to clean well.
Replacing is the best solution if you are convinced the pipe is not the factor.

 

[Sponsor]

 

[Adkroot]

The trapway and low points of the bowl the toilet build up mineral deposits from urine and even average water. That rough trapway surface contributes to WCs perform worse and worse over time.
You experienced the exposed places you can see, but the hidden path is impossible to clean well.
Replacing is the best solution if you are convinced the pipe is not the factor.

Thanks for the input and advice - I really appreciate it. Does the smooth enamel-like finish wear out over time making it more susceptible to buildup? Thanks again. Dan

 

[Breplum]

I don't think "wear out" as much as porcelain becomes less slick. Even Toto's CEFIONTECT

and all other brands special finishes diminish slickness over a few years.​

glazed and unglazed trapways eventually suffer similar.

 

[Sarg]

Just a suggestion : We have the same build up within the toilet rim and the trap.
Twice per year we do a cleaning .
I use Genuine Joe bowl cleaner ( Amazon )
We use a wet vac to remove all the water from the bowl and then using a funnel the mild acid is poured into the overflow tube in the tank. In our case it's amazing how much "crud" comes out of the rim jets.
I let it sit in the bowl for over an hour and then use the wet vac to remove the solution because we have a septic tank.
If we were on a municipal system I'd just flush it . The last time I poured two bottles through the overflow tube.
Makes a big difference.

 

[Reach4]

Hydrochloric acid puts out strong fumes, so lungs and eyes should be protected.

 

[Breplum]

The EdFred cleaner is a terrific cleaner that will "not harm septic tanks" and really does a good job.