Flexwatt wattage

[Russellm0704]

On most sites, there is the option for 6 watt or 10 watt for the 3inch flexwatt heat tape. will 6watt be enough to get the temps up to 90 or do i need the 10watt. thanks

 

[Russellm0704]

Hoping someone knows this, need to order the heat tape by tomorrow