As far as the lighting is concerned that is where I am still a little confused. I read from Doctors Fosters and Smith Veterian, (link to article below), that having a moderate level of lighting for Discus in a planted tank was recommended. In Watts/Gallon they said it should be 2-5 Watts per Gallon and I have an almost exactly 100 Gallon tank meaning that at a minimum I should run all 4 of my bulbs. Although I do definitely agree 100% with what you said about Watts per Gallon not being a proper unit of measurement because every bulb has a different efficiency and lumen output etc. Also from my last tank I remember leaving the lights on accidentally overnight once and seeing the tank much greener than normal. However I do need to reach a compromise so the plants can grow and if that means a bit more maintenance I guess I'll have to live with it, would you agree?
Article:
http
/www.drsfoster...2&articleid=524
Article first...that is basic "discus" advice that not everyone would agree with, but there are pearls of wisdom scattered throughout. As for the suggested lighting, this is a perfect example of why this won't work (using watts per gallon). There "2 to 5 watts per gallon"...what type of lighting are they using? T8 fluorescent like I have? Take my 90g, which is about 70 actual gallons when you discount the water displaced by sand substrate and all the wood: this would require 4 tubes (48-inch, 32w each) for 2 w/g, and 10 tubes for 5 w/g, which is ridiculously impossible to achieve. So do we then turn to your T5 and have 6 tubes for 5 w/g? You can imagine the blinding brightness this would be, and the poor discus would be shivering with terror.
None of my tanks have anywhere near 2 w/g even with my moderate T8 lighting. My 70g has two 32w tubes which comes close to 1 w/g, as there is likely less than 60 actual gallons of water. But my 115g 5-foot with two T8 tubes only has 64 watts which is about half a w/g, and the 90g not much more. I'll attach a couple photos to show the tanks. Any more light and I would have algae soup.
So the next thing after what I posted previously, is selecting the plants. Recognising that not all plants will thrive under the same level of light, or the same nutrient level, we need to find the plants that will thrive under the lighting we intend, and then we find the nutrient balance. Keeping in mind the CO2 issue, which is the one factor we cannot change but have to accept. This is where the experimentation comes in, and each aquarium is different. I have worked out the duration for my lights to 7-8 hours; even the increase in daylight during the summer entering the room through windows with closed blinds increased the light enough to increase brush algae. I solved this with heavy drapes that are closed all summer [this works when one has a dedicated fish room, but may not be feasible in the living room].
Trying this plant and that plant, I quickly found that some thrived while other wasted away. I have stayed with what works under my light, since for the sake of my fish I am not prepared to increase the light. Something else to consider is that many high-tech planted tank aquarists only have plants in their tank, no fish, so it is a different scenario. Unfortunately some of us think we can have that sort of aquatic garden, but there are ramifications. Anyway, I found that Amazon swords (the green-leaf species) do extremely well in my tanks; I use Flourish Tabs in the substrate so I can reduce liquid fertilizers (the liquid get inside fish, substrate tabs do not). You will see in the photos I have large swords,
Echinodorus grisebachii (often seen as
E. bleherae) in the 115g,
E. grisebachii and
E. major in the 70g, and
E. cordifolius [I think] and E. grisebachii in the 90g. The chain swords (the substrate cover in the 70g and 115g)
Helanthium tenellum (70g) and
H. bolivianum (115g) also grow like weeds. My crypts in the 90g are doing quite well, and I also have red tiger lotus in there, and seasonal Aponogeton. And of course I have floating plants in all my tanks for the fish, and these do lessen the light getting through so that must be kept in mind.
Would you say running the whole set for 8 hours a day would be acceptable or would the nutrient balance be incorrect or would it compromise the health of the disucs?
Light does affect fish. Not only the eyes, but every cell on the fish is light sensitive. Even when blind, they can discern day and night (studies have proven this) so light has a major impact on their homeostasis which governs their health. My friend Heiko Bleher might correct me if he read the next sentence, but so far as I know, there is no discus in the wild that lives in water that ever receives direct sunlight. Flooded forest is under the thick canopy, and most forest streams and rivers are so dimly lit plants can't even grow in them. The exceptions like the Rio Negro itself receives light and is planted, but the fish remain along the banks among the tangled roots and branches under the overhanging marginal vegetation which is quite dense. There are several videos on You-Tube illustrating this.
Once you decide on the intensity, then the duration is easier to work out. As you are not planning CO2, I would definitely only use two of the four tubes, and I would ensure a good layer of floating plants with this as it is still quite bright. One of each of the two spectrum you linked before should be OK. Then narrow down your plant species, as not all of them will thrive. There is another thing too, and that is keeping species limited. It seems to open up the space when there are fewer species of plants, probably because it is more natural. You will rarely find more than one, or maybe two, species of plant in any given stretch of river; flooded forests are the same with respect to aquatic (marsh or bog) plants, and the terrestrial plants will be more varied, but not much.
Feel free to ask questions, no problem there.
Byron.
)
