As I understand Chlorine Dioxide:
Warmer temperature means a shorter treatment time. I think MicroPur is speced for 70 degree water. If the water is 88 degrees, you don't have to wait as long. I remember an old rule of the thumb from chemistry that increasing the temperature 10 degrees C doubles the reaction rate. So, I figure that 88 degree water only needs half as long to treat. Conversely, 52 degree water would need twice as long.
You can adjust the treatment time and dose over at least a factor of 2. You can use a double dose (two tabs) and wait half the time or you can use a half dose and wait twice as long.
There is already a significant safety factor built in to the recommended dose, so you don't have to add your own safety factor to the manufacture's safety factor
You could consider using a coarse filter to get the cysts (Giradia & Cryptosporum) out of the water.
I hike in dry places, so the water often looks like a food source. I'll filter through a bandanna to get the big floaters and small swimmers out of my drinking water and then treat it with a double dose. If I have any question about the water possibly containing cysts, I'll wait at least 2 hours (with a double dose).
Here's a somewhat technical reference. They say that an 10 degrees C increase in temperature increases the inactivation rate by a factor roughly 3.
from the document above commenting on crypto (which is tougher than Giradia) "Based on a typical chlorine dioxide dosage of 2.0 mg/L for a water system, contact times of 115 - 915 minutes (2 - 15 hours), depending on temperature, are necessary to achieve the CT values in Table 3."
Note that organic matter and silt in the water will "soak up" the chlorine dioxide before it gets a chance to inactivate cysts. I also don't know what the ClO2 concentration is from one tablet of MicroPur.
"The CT is the product of disinfectant concentration (C in mg/L) and contact time (T in min)."