SO4 is the main anion in tap water, you drink it.
Does no harm nor leads to anaerobic conditions or any of that baloney.
Plants also take up this form of sulfur.
Anaerobic sulfur reduction bacteria requires
, not suggest or not sort of kinda maybe business...........it is obligate anaerobic bacteria, no O2.........
You can add lots of SO4(sulfate), tons of it.......and no reduction, even if the gravel 12 inches deep.
Does not matter, if there's no organic material.
If there's too much organic material, or the loading rate is high enough to cause the bacteria in the soil/gravel use all the available O2, then it can become reducing to H2S.
But you must have a rate high enough to prevent O2 from plant roots, and from the diffusion for that to occur and a large source of reduced carbon.
This is rare in most planted tanks.
Mostly due to dying plant roots/poor plant growth after a period of decent health, not the reducing conditions themselves.
In other words, black stank H2S is a result of poor plant growth in the root organs, which then leads to bacteria consuming all the O2 up(aerobes) eating all that organic carbon(we do the same thing when we eat carbs), which then allows for the sulfur reducing bacteria to use SO4 reduction as an electron acceptor instead of O2 (aerobic). Then you get H2S as an end product.
S-2 is the electron donor.
Heat cable people, power sand proponents, etc rarely have much understanding about the entire process unfortunately.
Good plant root growth cures it, and aquatic plants come from highly reducing sediments in nature, they are well adapted as long as they good growth parameters otherwise, to grow in very reducing anaerobic soils,.
It's not as simple as having just SO4 in tap.
Most harder tap waters are loaded with SO4.
If interested in more:
Dr Reddy is the
person to go to for wetland soils.