Thank you all for reading my post and replied with all the suggestions. i know my original post is long... maybe even paranoid but i am hoping that will help others trying to setup these filstar XP filters.
I also observed another fact that: IF the spray bar is placed above water and placed too close to the inlet pipe in tank, little tiny bubbles will get suck into the canister. and it will also cause water inside the canister to drop.
The propeller being used in these filter is water lubricated. so I think you dont want too low the water level inside your canister.
I can say I follow everything by the book and my filter is still trapping air(ie canister level dropping slowly) so I have been performing the procedure to restore flow every 2 days. I wish I can do without it.
I also observed another fact that: IF the spray bar is placed above water and placed too close to the inlet pipe in tank, little tiny bubbles will get suck into the canister. and it will also cause water inside the canister to drop.
The propeller being used in these filter is water lubricated. so I think you dont want too low the water level inside your canister.
I can say I follow everything by the book and my filter is still trapping air(ie canister level dropping slowly) so I have been performing the procedure to restore flow every 2 days. I wish I can do without it.