Finnex RayII Light Question

[JeepGuy91]

Hi everyone, Im in the process of getting my planted tank up to speed. I'm still figuring out how PAR's work and was wondering if ya'll could help me out. I currently have a 75g (48x18x18) and have one 48'' RayII light (rated at 39 watts). Was wondering if this is considered "high output or not as I cant read the graphs well. Heres a chart I found for the lights...

It would explain why I'm having algae and diatom issues since I wont be receiving my C02 rig until later this week. Im currently running a ghetto DIY setup with baking soda and citric acid. lol

I'm trying to carpet my tank with DBT so a high light output is what I'm trying to acheive.

 

[Fresh2o]

I am including the PAR chart for a 48" Ray2:

Based on this chart, the PAR will be 73 at 18" which is at the higher end of medium light. Without a decent, consistent CO2 supply, your tank will be an algae jungle. Is this enough light for growing DBT? IMO, yes assuming the CO2 and ferts are in great supply.
I tried DBT (HC Cuba) for a few months and all but given up on it. Would not stay rooted, even while super glued to stainless steel mesh. I do have a small clump glued to some DW and its doing fine. IT is even growing in a few terrariums I own. But I could not pull off a carpet with it. I am running 2 Finnex fixtures on separate times which deliver 65 PAR for 5 hours, ~110 PAR for 2 hours, and 45 PAR for 2 hours; pressurized CO2, PPS-Pro ferts.

 

[JeepGuy91]

Thanks for the info, I ordered the dr foster and smith auto c02 system so hopefully the money will be well spent! My DBT have stayed the same size for about 2 weeks, pretty frusturating. But yeah I plan on keeping certain patches of algae that airnt easily seen in the tank just to make more competition for nutrients once the c02 is added. If all else fails I hear dwarf hair grass is much easier to get to get going.