Is 20 wpg overkill for a glosso set up??

Get some tea bags as you should have boiling water in no time.

One of my favorite quotes about planted tanks comes from Kaern Randall who wrote:
Recently, in the typical American thinking of “more is better,” I’ve come across people using upwards of 5 watts per gallon on their planted tanks. While it is possible to manage such a system, it is more work. I have yet to meet a “high intensity” plant that could not be grown well in a tank of normal depth at around 3 watts per gallon. If the plant is not growing at 3 watts per gallon, look to other causes for the failure first.

You can read the entire article here http://www.csd.net/~cgadd/aqua/ah_main/mar1998.html
 
You can grow this plant fine at 1.5 w/gal FYI.
I've done it several times in 10 gallon tanks.
Much easier to control and have far fewer issues.

Sell the light, get a pair of 15w or a a single and add that.
Gloss and HC are not high light plants as many claim, they do just fine at lower light, they just grow faster with more, then later, they turn into weeds.

That is if you can keep up with the dosing and CO2 to get to that point.
Faster/more is not better.


Regards,
Tom Barr
 
AquariaCentral.com