Join Date: Nov 2012
Location: Broomfield, CO, U.S.A.
29gal 18" high
I'm super glad that there is a PC chart there (Thanks Hoppy), it seems like info available on them is becoming a bit scant. I suppose the tech is just getting old or something. I'm trying to get the lights right on my 29gal which is 30w x 12d X 18h.
I have a dual bulb 65W power compact fixture and I'm only using one bulb, a 6500K 65W coralife 22" bulb that's new. I bought the fixture second hand and it is a 'current usa' brand that seems to have an OK reflector. Based on the PC chart, when its sitting about 2.25 inches above the tank, (about 18 inches above the substrate), I should have around 40 PAR.
I keep getting algae and the light seems bright at that height so I just got finished raising it to about 25 inches above the substrate. My tank could probably be called 'moderately' planted.
In this case, it looks like I might have just under 30 PAR. Did I go up too high? Would I have that much more PAR just because the light is 65W, instead of the tested 55W? It would seem that being in the meaty part of 'medium' would not cause fast algae bloom. I'm trying to have it low-medium light (I do have co2) to avoid algae and keep my shade-loving Tetras and Rasboras happy, plus also avoid what my wife and I were calling the 'x-ray' effect of the bright light on the fish.
Are all of my plants going to die off at the bottom part of the stem or does this sound like a good range of height to start from for a low-medium light tank?
I guess I don't want to be way-overestimating the power of the single lamp only to learn that I needed to look elsewhere to solve my algae problem after all of the bottom plants start suffering. In my house, with my water anyway, so far, the lower the light, the less algae no matter the set-up (so far), so I'm kind of going off of that.