MuAq on a pre-existing poison

Following my snakey bjornaer on ... se-arelie/

If you use a MuAq spell on a pre-existing poison, what happens? Say I take some arsenic (medium wound, difficulty to resist 6) and then MuAq to increase its potency to Heavy - is the difficulty to resist the base 3, same as if you were transforming a base liquid to poison, or is it enhancing the pre-existing poison and therefore the difficulty is still 6?

If you say it's base 3, that means if you can cast a spell to transmute a poison to base difficulty 3 then any magus with a decent strength can develop an easy counter-poison. If you say the latter, that means people with access to a dubious apothecary can find using MuAq to make a poison very vicious.

The other question I have is regards to a venomous Bjornaer wanting to transform their own venom - will target personal (target the venom inside your own venom glands) with an Animal requisite and duration diameter be enough?

I put a comment up but I think WP lost it. Can you also transform water to poison with a base which doesn't use the CrAq guidelines for an incap poison.
And I think the last spell on the page needs range touch too.

Thanks for pointing that out, I've edited the spell to add the touch range.

No sign of your comment, wordpress says nothing pending sigh this blogging technology isn't always as user-friendly as they claim.

The problem with transforming water to poison and vice versa is the massive change in volume - a single dose of poison is the equivalent of thousands of litres of water, so even a large barrel of water may not get you a full dose and if you try to turn poison to water, the recipient will need to vomit out more gallons of water than their stomach can hold, or a snakebite will suddenly gush like a fountain.

But I think the OP wants to change poison into a stronger poison. I am guessing if you had a medium poison and wanted to change it into a heavy poison that is base 4. To change it into a fatal poison is base 10.

You're completely transforming the substance, neh?
So I don't really see why the base difficulty to resist the new poison shouldn't be 3.