Having usb problems on mac book pro using asteroid

[liquidcoin]

I'm running maverick on mac book pro.

i have one 49 hub block erupter and 20 antminers.

asteroid is only seeing ten. All 20 antminers show up in the system info under usb but not in the asteroid.

I brought 10 and they work fine, but when i brought another ten there not working.

I rebooted asteroids 50 times and same thing happened.

I also was able to get the other ten antminers to work but nothing pass ten.

I'm using atx switching power supply with 430w peak power. model EP-43060

anyone have any suggestions.