fal3 said:
Wow! Thanks for such a detailed reply. Ok first, The light is on for most of the day, now its on from about 10am-11pm. However when i had the plants previously it was on for longer. Around 7.30am-11pm.Its a tube. It has the two prong things at each end and it slots in to place. Sorry, really bad with lights and stuff
As for the ferts, I used easylifr easycarbo for the carbon. And easy life profito I think it was called for the rest of the nutrients. I also used api root tabs and put them where the pack told me to.
OK, now we're getting somewhere. The fluorescent tube, I will assume is T8 rather than T5. It will (should) have this printed at one end. The "T" number refers to the tubes diameter in eighths of an inch, so a T8 is 8/8 or 1 inch diameter, while a T5 is 5/8 and thus thinner. There is another possibility, and that is a T12 which is 12/8 diameter and thus much thicker. This T12 was the original fluorescent tubes and are no longer being made as the T8 iuses less energy, etc. The T5 will not fit a T8, and vice-versa; the T12 will fit T8. Perhaps you could let me know which you have, but I will continue for the present assuming it is the standard T8.
One tube will be plenty of light over your 15g tank. I had this same setup many years ago when I had a 15g. At this point, we come to spectrum, which refers to the colour wavelengths emitted by a tube. Without going into detail which would only bog us down, I will just say that your best tube would be one with a "daylight" spectrum. This is usually identified by the Kelvin number, and you want somewhere between 5000K and 6500K. I'm not sure what tubes may be available in the UK, but other members likely will. Akasha72 and daizeUK come to mind, they have both posted on lighting.
As for duration, you want this much more controlled and regular. This is better for the fish as well as the plants. I am going to get a tad technical here in order to explain things. Plants grow by photosynthesis, and this is driven solely by light. Different plants have different levels of light needed to photosynthesize, from low light requirement plants like Anubias, Java Fern, Java Moss, to high light requirement plants like most of the stem plants and usually most of the so-called carpet or lawn effect plants. In between are plants like swords, crypts, Vallisneria and others. Now, this is very general, but it gives you the idea. Intensity is the main issue here, obviously, with low to moderate to high light. The intensity must be sufficient for the plant species; leaving the light on longer does not make up for light that is not bright enough to drive photosynthesis for that particular plant. However, once you have the intensity suited to the plant species, then we come to duration. For the plants you initially mentioned, your single tube is more than adequate intensity (spectrum enters into this as I said above). So this brings us to duration.
Plants that have sufficient light intensity will photosynthesize to the max, i.e., as much as they possibly can. However, at this poiint the nutrients enter the equation. Aquatic plants need 17 specific nutrients, and some of these have to be in protortion to each other; here again I'll leave this aspect or we'll never get through this. Using your comprehensive liquid fertilizer will deal with this. I don't know the Profito line myself, but other UK members use this and it appears to be good. However, as the plants use these nutrients, they become exhausted. And at that point, regardless of the light, the plants cannot photosynthesize fully so they slow down and may even stop altogether. So we need to balance the light duration with the nutrients. You don't mention algae issues, but usually when the light is on past the available nutrients, algae takes advantage.
Another aspect of duration is that plants, just like fish and all animals including humans, must have a period of rest or they literally "burn out." With plants, this is a period of complete and total darkness, and it has to be for several hours within each 24 hour period. You can adjust the light/dark somewhat, but remembedr that the light will drive photosynthesis and the plants have to have everything on hand to do this. Most of us find that around 8 hours a day of tank light is usually workable. A timer to keep this regular is a good idea. The period of tank light can be adjusted to be when you are normally home to enjoy the aquarium.
The liquid Profito is all the fertilizer you should need. Substrate tabs are not necessary in this small a tank, as you will not have plants that are heavy feeders as one does in larger tanks where these help as additional to the liquid. The API tabs also have a habit of making quite a mess if they are disturbed. As for the carbon, I personally would not use Easycarbo as here again in this small a setup you shouldn't need this. There is a fair amount of natural CO2 (carbon dioxide) occurring from primarily the breakdown of organics (fish waste) in the substrate, and in this size tank with the plants you will have, this should be adequate. To avoid the natural CO2 running out, we limit the light duration. Again, around 8 hours should work. You can always tweak this later, once everything is settled and you observe the plants' response (and algae).
To some plants. Once we know the tube is a good spectrum, and you have the duration down, some plants that should do well include Anubias and Java Moss (you had these previously); these attach to wood or rock--you didn't mention it, but if the rhizome of Anubias is buried it can rot, so it is best attached to wood or rock or decor. As for other plants, the chain sword will thrive and spread via runners. The corkscrew Valisneria is another, especially if you have moderately hard water. I would avoid stem plants as they will grow so fast in this setup you will be continually pruning/trimming, though that is up to you. But some will need more light and CO2 that what will be available. Floating plants are always good, as almost every forest fish appreciates a roof above them to shade the light. Enough light will get through for the lower plants I've mentioned. This is where the stem plant Pennywort is ideal. The roots are not too extensive as some floating plants, so it will do the job without taking up too much space.
Feel free to question anything here, but this is I think a start.
Byron.
