It's just that i read everywhere, hairgrass is a high light plant that worried me.
So i hope my hairgrass will do well at 4.5 watt per gallon (is that really the count? i read that formula can't be applied to smaller tanks).
If anything, you have too much light, you have HLD, high light disease.
Hair grass is not, like most all FW plants. a high light obligate plant, if fact, there is not a single species that cannot be grown at about 2-2.5 w/gal unless the tank is really strange shaped etc.
Folks have never bothered to test light and make assumptions, much like they did about CO2, nutrients etc.
To make matters worst, they have never bothered to test light in tanks at the plant leaf surface with the proper units such as micro mole/M^2/sec etc,m instead using some green light lux standard that is focues for our own perception.
Another issue is that many folks about 7-8 years ago, of which there are few today posting etc, used 2 w/gal or less, heck........that's all that was availble for most of us at the time prior to that.
HLD is namely a USA disease, few others seem to suggest or tell folks that hair grass requires high light.
Another problem is the types of FL lighting have changed and the reflectors and T5/PC lighting have developed and add even more light per watt.
More light is not better, it places more demand on CO2 and nutrients and that can give folks problems by giving you method adjustments that use to work well on the lower lighted tanks, but now cause issues at higher light.
Non CO2 vs CVO2 methods are one example of what happens when you add more light, you need more CO2, then nutrients if you add the CO2.
The amplification of growth has it's trade offs, but many are too stubborn to acknowledge it and use that knowledge to modulate their routines to reduce the rate of growth. Some still want break neck growth, but not after a couple of years, it gets tiresome.
Having the control to do slow, moderate and fast growth is a far far better approach. If you are new, suggesting you need super high light would not be a good idea.
But they still do it.................:icon_idea
Several shops and scapers routinely use 1.7 w/gal of T5 lighting and have super short dense hair grass.
Miracle?
No, common sense and seeing if you can limit the light and supply good nutrients/CO2.
Stop off at Aqua Forest if you do not believe me.
2x54w on a 65 gallon tank and it's enough light for any ADA style set up you and or anyone might have in mind and a nice short lawn of hair grass.
Shading is an issue as mention it will grow taller if that is done.
Regards,
Tom Barr