Maracyn oxy poisonous to snails?

[OdinValknir]

I'm treating a fish that looks to have scraped its "nose" on something and has a fungal infection. I don't currently have a hospital tank so I dosed the whole tank which does include other fish as well as a bunch of pest snails. 

 

Maracyn oxy does say it's poisonous to invertebrates, and I haven't seen any active snails in a few days. I'm guessing it killed all the snails. Problem is......

 

Now I've got a small ammonia spike. I just did a large probably 60%+ water change to help dilute and obviously dosed prime. 

 

I guess my question is, with the amount of small pest snails I saw in there, what kind of ammonia spike could I be looking for? I have to be out of town for work and probably not going to be able to do daily water changes. 

[Chick-In-Of-TheSea]

Vacuum as many pest snails as you can from the substrate.  Dose beneficial bacteria (such as Fritz Zyme 7) in case the medication killed the bacteria on your filter.  If you are using a hang-on back filter, you can take an extra step and put an ammonia removing pad into it before you leave for your trip.