Minimum Flow Rate for Ozonator on Outdoor pool

[macmini]

Some specifics on my pool first:
- 18k gallon outdoor gunite pool with Pebblesheen
- Hayward Ecostar Pump
- Hayward 1HP Super II Pump for waterwall
- Gas heater
- Prologic PS8 with Aquapod
- Ultrapure ozonator
- Hayward C4030 cartridge filter

I have set the variable speed pump for my main pool filtration to 900rpms (30%) for 12 hours/day. The pump is extremely quiet and only uses 90-100 watts. The ozonator tube is installed in the pump basket drain port. However, tthe ozonator flow meter is reading 0 flow. The black bead in the flow meter is at the bottom regardless of the ozone setting I dial in. Even at the maximum setting, the black bead stays at the bottom.
Ozone is not my primary sanitizer (started using the BBB method from day 1), but the system is installed already and I want to take advantage of any benefits the ozonator can provide.

Is there a way to increase ozone production when the pump is running at low speed or is ozone still being delivered but the flow meter has to small of a range to display this?

Thanks.

[PoolDoc]

Ozone is not my primary sanitizer (started using the BBB method from day 1), but the system is installed already and I want to take advantage of any benefits the ozonator can provide.

Not to put too fine a point on it -- but you'll get the same "benefits the ozonator can provide" an outdoor pool with it turned off, as you will with it turned on.

[PoolDoc]

Here are several related threads, that cover the topics in more depth:

http://www.poolforum.com/pf2/showthread.php?332
http://www.poolforum.com/pf2/showthread.php?5115

http://www.poolforum.com/pf2/showthread.php?15920
http://www.poolforum.com/pf2/showthread.php?14621