65W light on 20 gallon high tank. Light is on 6 hours/day

[gu2high]

I am setting up a 20 gallon high tank (16" high, but after less substrate, it is only 13" high), with a Coralife 65w PC light. If I let the light on 5 or 6 hours per day, do I need have pressurized CO2? I have low-medium light plants.

I am planing to have shrimp and other very friendly fish like cory cat and bristlenose pleco or fry in it only. I think they may like dark more and room light is enough for rest of daytime.

[neilanh]

I think you'll find with that setup you'll eventually want CO2. Can probably get away without it for a while though. I have that same setup and it does very well with CO2.

[travis simonson]

I with neilanh, you'll probably want to consider CO2 somewhere down the line if you plan on continuing to use that light. Light intensity and photoperiod are not linear when it comes to trade-offs. I suspect you may run into to some algae issues sooner or later, even with a six hour light-cycle. I hope I'm wrong though

[gu2high]

Yes, I know I will have algae problem. I want to try it first and I want to raise red cherry shrimps and American flag fish fry, may be other shrimps and snails too. They like to eat algae so I hope there is enough algae for them to eat, but not too overwhelming though. If really need CO2, I may use my current DIY CO2 bottles first.