Jeez guys
, I was just stating the fact that I would much rather have an AquaGro over my nano than my Arc Pod. I presumed that because Kogre seemed a pretty intelligent guy that he would understand that there is a need for CO2 and extra nutrients! Kogre, sorry to have this on your thread and feel free to get a mod to delete it but with the size of the tank you would need more lighting than you might need over a 60cm tank That's all I was saying. I hope you guys agree with that.
The reason we are so militant is that the world has been programmed to think that more light is always better. Whenever giving advice to newcomers about lighting we should always preface our advice with the caution that higher light intensities generally are associated with higher risk of plant health problems. There are many intelligent people who do not know this, and who experience failure as a result, therefore, intelligence has nothing to do with the success of a planted tank. Knowledge is the key. The OP seems fixated on WPG, which, for his size tank is a completely meaningless parameter, and so it would have been better if you had clarified that point instead of extolling the virtues of one system versus another. This is critical because peoples lighting choices are THE major contributor to problems in the tank. We are much too quick to talk about what WE would prefer when we really need to consider the needs and the experience of the person asking the question.
The OP also mistakenly believes that in order to grow carpet plants he requires a lot of light. This is another popular fallacy that you ignored, and it would have been better to clarify this point, that carpet plants simply grow faster, with high lighting but they require better flow and distribution in order to flourish.
To give context in response to the OP's question, ANY light is good for plant growth and health. The OP did not mention what kind of lighting came with the tank. It has been assumed that the lighting that comes with the tank is poor. It would have been better for the OP to describe in detail what kind of lighting the tank has an option for. It may in fact be poor, but we still need to assess the configuration as it may be an easier matter to modify the stock lighting instead of performing a new installation from scratch. With this in mind, one has to then think about the other issues such as cost, ergonomics, installation and power consumption.
Traditional T5 or T8 lighting systems require only ballasts, fixture and tubes. No controllers are required. The ballasts can be mounted in the fixtures or they can be separated so as to reduce weight on the fixture. There are plenty of options as this technology is mature. In post #1 it was mentioned that a series of 30 inch Arcadia tubes was preferred. If the installation is not difficult then this is as good a solution as any. Each tube will require it's own ballast, which can be remote. That would remove the weight from the fixture. Alternatively, few, longer tubes can be used depending on the fixture or hood. It's just not clear regarding the choice of fixture.
Depending on budget, hanging fixtures can also be used. The advantage here is that the fixture can be raised to control the light intensity and spread as well as the choice to leave some bulbs off. Even a metal halide hanging fixture can be used, however they tend to be more expensive and power consuming.
The LED fixtures can be used and they do not require the use of a controller, however a controller allows you to reduce the intensity and this is much more important. When you buy an LED fixture you typically get the tile, which is composed of the cluster of bulbs, as well as the power supply. The controller is an extra cost. Again, if you can afford this combination, then NanoJames contention that this is "better" is valid in the sense that it is a cleaner, neater and more controllable lighting system, and that's why it should be considered better, not because it is brighter, because massive brightness is actually a disadvantage.
So hopefully, this gives you a better general perspective on lighting systems. Apart from all that, in my opinion, what you should be more concerned about in a CO2 injected 180 gallon tank, is what level of pump strength or filtration strength you will have and how you will dissolve and distribute CO2, because that will have a greater effect on the health of your plants than what kind of lighting you have.
Cheers,
I still reckon that LED is your best bet as you could also bear in mind running costs. LEDs are going to be cheaper in the long run but most likely more expensive at the start! Your choice...