You mentioned citric acid not completely eliminating the PM. It won't and nothing else really does. So it's not a problem with the citric acid so much as it is possibly your environment and the fact that once a plant has PM it can and usually does always come back because it lives within the tissue. What you need to do is keep the PM at bay and basically grow out of it and that can take a few cycles. You're going to want more than just one spray. Use Regalia to keep the plants in defense mode, it'll keep them strong and make it harder for the PM to infect. Use it up until week 2 or 3. PureCrop1 will kill PM on contact and keep the leaf surface PH high which PM doesn't like, and you can use the PureCrop1 daily and up until harvest but it will burn hairs in bloom. Oxidate 5.0 (10ml per gallon) will kill pm but it doesn't have a lasting effect, but it doesn't burn hairs. If I were you this is what I'd do..
Regalia: 30ml/gal weekly from the seedling/cutting stage up until week 3 bloom
PureCrop1: 30ml/gal weekly from the seedling/cutting stage until week 3 bloom (if you spray Regalia on a Sunday spray PureCrop1 on a Wednesday)
Oxidate 5.0: 10ml/gallon every 2-3 days after week 3 bloom.