Because I don't have it on a timer do I turn off my Co2 at night and turn on airstones or do I leave the Co2 on and turn on airstones?
I would just leave the CO2 running all the time.
If you turn it on and off, there is one day that you will forget (not to mention it is a hassle).
Where is the optimum place to put the diffuser?
At the bottom of the aquarium, directly under the filter return. This way, any rising bubbles are pushed around by the flow of water, allowing more time for CO2 to dissolve.
What is the optimum rate of co2 ie how many bubbles per sec?
Bubbles per second is not a good measure of how much CO2 is actually being dissolved. You should be looking at CO2 concentration, and not flow rate. You could have a very high flow rate, but poor dissolution of CO2, meaning your concentration would be low.
How long before I see growth?
I always give any changes in a planted aquarium at least 2 weeks.
- Do I stop dosing execel or reduce dosing?
You can stop using Excel if you are injecting CO2.
With me now using pressurized Co2 how importan will be the testing of PH/KH/GH do I check everyday, every WC or based on observations?
I do not test my water; the most important thing to doi s to watch your livestock to ensure that they are not being suffocated by the higher levels of CO2.