0 Nitrates 0 Phosphates, hornwort starving

[cervelo]

Hi everybody,
I have a 60 liters tank, 3/4 full (tap water with bio conditioner, quite hard, Ph 8), 25 Watt 6500K CFL, sand substrate, no CO2, no fertilizers, 10°C / 25°C winter/summer.
Inside there are some anubias, Java fern, Java moss, fontinalis antipyretica, all of them thriving, and some hornwort (Ceratophyllum).
Hornwort has been growing like crazy for 2 years but since a few months is slowly dying.
Today I tested Nitrates and Phosphates and the result was 0, so I guess hornwort sucked all nutrients and now is dying of starvation.
I'm not very keen on fertilizing (also) because in the tank there 4 1-year-old newts and I'd like to know how do you cope with this: fertilizing? Discarding all fast growing plants (this would be strange to me)? Fertilizing in some "natural" way not harmful for newts?
Any idea would be most appreciated

C.

 

[JM29]

Hi !

Hornworts are known to be very competitive.

Since we are in winter, I suppose your temperature is nearer from 10°C than from 25C. So it may be normal for the hornwort not to grow fast and they often lose part of their leaves in winter. You don't mention your day length.

About fertilizers, your newts probably release some nitrogen and phosphorous. After some bacterial action, they are converted into respectively Nitrate and Phosphate, but the plants (especially hornwort) possibly uptake all as soon as they are produced.

One solution could be simply have less hornwort at the moment. When the temperature is higher, the newts will eat more and the Nitrate and Phosphate production will be more active, with benefits for the plants.

 

[JM29]

The high pH of your water could also be a problem. Phosphorous is not very available for plants at such a value.

 

[cervelo]

Thank you for your reply.
I know Ph is a bit high, old issue, I just added some alder pines and oak leaves.
Day length is 7 hours, and since autumn I added a few Watt more and removed the lamps transparent plastic protection; so new growth in hornwort, before beginning to die, was reddish.
I guess I have to wait springtime to see how things evolve, It's just that in past winters hornwort wasn't behaving this way.
I've just read some posts here on Caudata that sometimes hornwort simply dies, so maybe it has just reached the end of his life cycle.
What I really wanted to know is if you use to fertilize (which I don't want to do), and you confirm that there's no need.

C.

 

[JM29]

No, I never add fertilizers in the water. Waste from the newts usually provide enough nutrients.
As for hornworts, most of them usually die in winter, or at least lost a lot of leaves (low temperature, short day light) but there remains a dense terminal bud which waits until spring.

 

[cervelo]

Thank you very much, waiting springtime :happy:

C.