To mitigate radon, is a "positive" basement pressure possible during balancing?
Ventilation/ pressurization based solutions can be advised, and often are in commercial design. In residential a reduction of 50% average Radon readings is usually considered an upper limit with HRV/ERV mitigation. Modifications to the recommended HRV install with some exhaust drawn from near the basement or crawlspace floor can improve this. If you have measured your intake/exhaust volumes and adjusted for slightly more fresh air in , say 15%, than indoor air out (and you don't want to T into to your HRV pipes to modify) then you've done all you can with your HRV. Volume is not pressure. Measuring airflow alone gives you zero idea of across slab or exterior wall pressure differential. This is the force behind soil gas, Radon, entry. Maintaining a small level of vacuum, just a few Pascal usually, under the slab through your Radon pipe should not take more than the installation of a small quiet fan and should yield 75 - 95% Radon reduction.