PPG Omni MP 170 over Picklex

[KVP]

I have sheet metal that was treated with Picklex about 2-3 years ago. It's been kept dry and remains rust free. I plan to use Omni MP170 epoxy primer but see it has zinc orthophosphate as a component. Picklex says it's a no-no to use a primer with acid in it. Can I use this primer or do I have the potential of creating a problem for myself short or long term?
 

[CNKS]

I have used 170 over Picklex several times. I think what the Picklex info means is not to use etch primer, which has acidic properties. Picklex itself contains phosphoric acid and etch primer might result in too much acid causing the paint to lift. Do not confuse the orthophosphate with phosphoric acid, they are not the same. If mine I would sand it again and use wax and grease remover immediately before priming, as I do not like painting over any kind of residue. You can probably get by with scuffing it with a scotchbrite pad, then wax and grease remover. However, instead of that (due to the time since it was applied) you might apply Picklex again, let it sit overnight and then do the above. This will neutralize any rust you might miss.
 

[Rod (NH)]

Ditto what CNKS said. Picklex should not be used over any etch primer product. The OMNI MP170 has no etch component (e.g. phosphoric acid) in it and therefore is fine to use over the Picklex. I've done that many times with great success. Like CNKS, I don't like to apply the 170 over any obviously loose deposit so I just scuff any of that white stuff off with a Scotch-Brite pad prior to applying the 170.
 

[KVP]

Thanks for the prompt replies and the valued input based on your experience with both products,ROD(NH) and CNKS.
 

[CNKS]

You're welcome