Anyone familiar with salt water chlorinators?

[e100]

I'm seeing some strange voltage and current readings.
I believe that my unit consists of a mains fed triac which runs into the primary side of an isolation transformer. The low voltage output winding is centre tapped, and goes to the chlorinator +ve electrode. The -ve electrode return wire splits and goes to two thyristors that return to the current to the two transformer ends.
The thyristors provide rectification and are also used as gas detection switches by running the gate wires to the void above the chlorinator. When filled with water, current travels from the chlorinator +ve electrode through the water and to the gates.   

Measuring the voltage across the chlorinator electrodes, at the triac minimum setting it looks pretty normal although there is a small bump on the left.
I speculate that the 3v offset is due to the chlorinator electrodes behaving as a battery (is this correct?).
As I turn the triac dial, the bump on the left gets bigger and doesn't look like any pictures I can find on the web.
The current waveform tracks the voltage waveform and goes to zero at the 3v threshold. The peak current is about 15 amps. The bump is delivering current.
Picture below

Does anyone understand what's going on?

[tautech]

Looking at the screenshots and the frequency reported as 100Hz it's 2x your line frequency plus we see the amplitude increasing as the Triac ON time is longer. Longer ON time = higher amplitude = higher current.
I'm guessing the Triac ON time is controlled by phase control, that is some time after zero crossing of the AC for minimum current to shortly after zero crossing for max current.

[e100]

I should of posted this earlier, here's a drawing showing what I'm asking about. What's the little bump to the left of the main thyristor trigger point?

(The mains frequency is 50Hz)