I recently did a water change 2 days ago and I put some API stress coat in my tank. Today i finally found a shop that carries Purigen and Prime. I know that the API stress coat will foul the purigen and make it toxic so my question is...what do I do? Do I have to do another water change before I put the purigen in? Or does the fouling and toxic process only apply when recharging purigen with API products instead of using Prime?