Vallisneria spiralis is not growing well...

[DazzleDiscus]

I've had a few plantings of Vallisneria spiralis in my 29gal tank for about two months now, but it is doing worse. When I first put planted it, all the old leaves slowly dissolved/melted away. A few weeks after that I noticed a few new bright green leaves coming up, but later on realized that these too were dieing off...
The tank is low-tech, with no changes to the lighting fixture (24in. bulb) since I bought it 6 years ago. (it is a plant light) I don't dose any fertilizer, mainly because I am not knowledged in that, and none of the fish eat plants. I am going to get a new light fixture with bigger bulbs which will increase the lighting a lot, but am wondering if that is the main problem...

Any advice would be highly appreciated.

[Shadow]

My experience with Vallis, only plant the root otherwise it will melt away.

Bigger bulb, assuming higher wattage, will require extra CO2 as well as fertelizer. With low light, 2W/gall, you can go away without CO2 and fertelizer.

So you might want to post more detail, what is your light wattage, CO2, type of gravel, kH (if you know).

[luenny]

Do you do large water change recently? This may cause them to melt too.

[DazzleDiscus]

umm... yeah sorry I didn't post the water perameters... I'm not able to do it right now, I'll post them when I get back home.
I don't add CO2, type of gravel is small, river gravel- I didn't add any base fertilizer for I didn't know I should have if I wanted plants. Light is a little less than 2W/gal. But as I have said, that will soon change- probably next week or so.
There are not many plants... a few small plantings of dwarf hairgrass, two types of bulbs that I haven't looked up yet (these are fairing pretty well, yet have slowed growth since I moved them to the back corner, I'm thinking it is the amount of light hindering them. They still send up a few flowers now and then.) three onion bulbs, and some tiny dwarf lily pads I brought in from my garden pond. They are growing well and have numerous leaves on them.

I do a 20-25% water change every week, and haven't added any chemicals/salt to the water in well over 8 months.
I will post the water perameters later on today if I can.

[DazzleDiscus]

I'm sorry, our phone line has been down for quite a while so I couldn't post the water parameters until now. Somehow a tractor unknowingly dug up the phone line...
pH= 7.1
GH= 3*dGH (53.7ppm)
KH= 6*dKH (107.4ppm)
Nitrate= 10ppm
ammonia and nitrite both shown as 0.
I'm not sure how to use the GH/KH knowledge, and wether to post the dGH or the ppm.
Something that might help: I've noticed the past week that my lotus's new leaves are sortof rotting at the edges and only in a few places. Also, some new java fern leaves have splotches without any green color. They are kind of see-through. Sounds to me like a mineral deficiency of some kind. Any suggestions?

[DazzleDiscus]

Eveything that I have read about Vallisneria spiralis says that it is a very easy plant to grow- but I have not found any parameters to go by. I'm guessing I shall have to add fertilizer of some kind, but not sure which one(s). Does anyone have a suggestion? Please try to keep it simple though- I've already got a glimps of how complicated it can turn out to be! I don't want to have to worry about co2 equipment.