what is "normal" lateral lines?

So like others I was having issues. After my research, at the time it seemed an aerorator was the answer, ch-ching $1500 later got one installed. A few months later the black sludge from the yard is gone!

Yay!

Then ~6months after that, ponding over my tank =( It seems the 'silver bullet' wasn't the answer, or I had compunded issues: I do have a single chamber tank, and high clay content soil, hard/well water with salt softner. That seems to be a deadly combination too; and could be why many folks around me have the sprayer style tanks (not sure of the name, it empties off fluid like a sprinkler)

So more research, finally found this place, Try oxy clean to 'clear' the lines, tried that, no help. Try jet washing them, bought a clog hog, seemed they were clear, I did get a little black sludge to come out; but thats all, the hose went it's full distance easily.

So then tried septic seep, it says it breaks up the 'hardpan' of clay soil & salt, and aparently oxy clean breaks down into salt; and that's been my 'homemade' laundy ingrident for years.

Well it's been about another 6 months, no more flooding over the tank, altho it's been more drought than rain in that same period.

BUt now to my question, I still have the ends of my lateral lines dug open, and even after adding septic seep, 2 of the 3 are always holding water, the 3rd only at rainy times.

So should they always be holding water, or should they 'dry' out at normal water usage?

Again nothing backing up to the house; not overflowing the tank?