How to open zoos?

[Kent E]

Everyones zoos always appear to be open. Mine are closed half the time anything I can do?
Kent

[mgk65]

Mine open and close periodically.

If they are closed more than open, more than likely there is something they don't like.

Check you water parameters.

What kind of lighting do you have? Zoos can be very light tolerant; living from 55w PC to 400w MH. However, anything dimmer and they have problems.

mgk