Some of the stems and leaves of my L. repens are blackening and then 'wilting.' I'm not sure if it is exactly black, I'm a little color challenged, but not completely color blind. It's definitely darker. I've got leaves separating from the stems and suspending on the tank surface too.
The tank is a 10 gallon with 15 Watt general aquarium/plant fluorescent tube in standard reflector. The goal of the tank was to go low tech and balance the bioload. I have an 18 inch section of 3/4 in. diameter PVC
half filled with gravel as an external filter and current generator. A small pump lifts water from the bottom left and the pipe returns to the top right. The substrate is terraced using tiles so water flows down across the gravel through the planted region in the tank bed to the pump. The water surface is rippled without the significant bubbling I've seen on my power and UG filters on other tanks. I'm hoping that I can remove the DIY filter at some point and just pump water directly from Lower left to upper right to create that current/surface disturbance.
The L. repens shares the tank with a few bundles of Valisneria spiralis, a small offshoot of java fern, six neons, a juvenile Cory and a multiplying herd of hitchiking pond snails.
After identifying the snail as the "garden variety" pond snail, all references (and my observations) do not identify them as a hazard to the plants, just algae grazers. They slide and glide all over leaves of both plants. Observations of particular leaves have shown no damage from the snail travel.
The tanks stays mid 70 temps and recent tests had nitrates around 10 ppm
with a pH of 7 and a KH
of just two.
I know this means the CO2
is a little low, but both plant species have been putting out new healthy leaves. Especially the V. spiralis. I've added 1/8 teaspoon of baking soda to each gallon of water during changes and topping off to promote the KH
value a little. I don't think it's had a significant effect, but it made me feel like I was trying!
so I think I have three questions I need help on:
is this blackening followed by shedding of leaves a natural aspect of L. repens?
is the observation simply due to a low CO2
- should I need to fool with a yeast cell or step up the Khardening with bicarbonate?
is it possibly a plant parasite (and if so, what would I do about it)
any and all advice is welcome, I do not have photos of the tank at this time.
Oh, the tank lighting is timered to 4 hours in the morning and 5 hours in the evening.