Next, Chapter 48:
When, therefore, the boundary and limit, that millennial interspace, has been passed, when even the outward fashion of the world itself— which has been spread like a veil over the eternal economy, equally a thing of time— passes away, then the whole human race shall be raised again, to have its dues meted out according as it has merited in the period of good or evil, and thereafter to have these paid out through the immeasurable ages of eternity. Therefore after this there is neither death nor repeated resurrections, but we shall be the same that we are now, and still unchanged— the servants of God, ever with God, clothed upon with the proper substance of eternity; but the profane, and all who are not true worshippers of God, in like manner shall be consigned to the punishment of everlasting fire— that fire which, from its very nature indeed, directly ministers to their incorruptibility. The philosophers are familiar as well as we with the distinction between a common and a secret fire. Thus that which is in common use is far different from that which we see in divine judgments, whether striking as thunderbolts from heaven, or bursting up out of the earth through mountain-tops; for it does not consume what it scorches, but while it burns it repairs. So the mountains continue ever burning; and a person struck by lighting is even now kept safe from any destroying flame. A notable proof this of the fire eternal! A notable example of the endless judgment which still supplies punishment with fuel! The mountains burn, and last. How will it be with the wicked and the enemies of God?
Tertullian is confirming the destinies of the human race after death, either eternal life or eternal death, giving no evidence of universalism. The healing fire that is present is not a restorative fire, but simply fire that continues to burn, as if fuel is constantly being fed to it, prolonging it.
And finally, Chapter 49:
"These are what are called presumptuous speculations in our case alone; in the philosophers and poets they are regarded as sublime speculations and illustrious discoveries. They are men of wisdom, we are fools. They are worthy of all honour, we are folk to have the finger pointed at; nay, besides that, we are even to have punishments inflicted on us. But let things which are the defence of virtue, if you will, have no foundation, and give them duly the name of fancies, yet still they are necessary; let them be absurd if you will, yet they are of use: they make all who believe them better men and women, under the fear of never-ending punishment and the hope of never-ending bliss."
The argument that Tertullian means only for a time doesn't work in light of what he is saying and it's a similiar statement to what I and others have said. If hell is not eternal and conscious, neither is heaven. You cannot have one that is eternal but not the other.