If nobody ever tried anything new than we'd all still be using compact bulbs or driving model T's.
Like I said I'm not sure exactly what killed them and all I did was follow the instructions on a bottle of Phosphate Rx which is also tried and true.
I'm not trying to discourage research, quite the opposite. I am just weary when experimenting with chemicals on my DT - especially dumping in as much as you did
Your dosage wasn't anywhere near the right way to dose Phosphate RX, which is why you may have killed your red bugs (and likely more). Dosing 30 drops in a 55g tank would reduce your phosphate by just under 0.5ppm (10x what you should have in your tank) in the course of a single day - multiplied by 3 means you stripped the equivalent of 1.5ppm of phosphate from your tank. If your tank had 0.5ppm of phosphates to remove in a single day - your acro wasn't alive to begin with. Since you clearly couldn't have 1.5ppm of phosphates to remove from your water - it means there is probably free-floating lanthanum chloride in your system and absolutely no phosphates in your water column. I don't know about you - but extremely high lanthanum levels and absolutely no phosphate seems very troubling to me.
There is a way to experiment and a way to likely kill things. Of those options, what would you consider dumping a chemical into your tank you know little about at a dose 10-30x what it should have been?
Again, not trying to say don't research this - I am just saying be careful and for
display tanks I would stick with the tried and true...
I can tell you with 100% confidence that using Lanthanum Chloride, specifically Phosphate RX,
at the correct dose will not kill Red Bugs. I use this in my tank at work which I occasionally store shipped acros since there are none in the system (If I have to wait for my QT to be empty at home - I never mix new acros with acros that have been in QT for a long period of time) and have received several acros with Red Bugs that this had no effect on. Acros have been in this system for over a month without any signs of red bug death while using Phosphate RX. I use this every week or so to bring phosphates back down to 0.03ppm (According to the ULR checker) if my WCs don't bring it far enough down.
As for the correct dosage - directly from the Phosphate RX Bottle:
Six drops of Phosphate Rx will lower your phosphate by .5 ppm for every 10 gallons (37.9L) of water.