Help with Elodea densa

[Sanniejop]

Hello,
I need your help with this beginners plant.
Some time ago this plant was growing realy well. But at some moment it started to get brown tips and finally stopped completly with growing. After some time it started growing again and everything seems to go into the right direction. But now i see the same symptoms starting again. I cannot figure out what the cause is. Other plants seem to do well exept the hydrocotyle. It also shows pale stains on old and new leaves.

I have a suspicion it has maybe also to do with stems reaching the surface close to the lamps. Not all stems show the symptoms (yet)

So here the details of my tank.

1. Size of tank.
175L 45 Gallon

2. Age of the system approximately.
5+ years

3. Tap water parameters.
See attachment

4. Filtration and Media.
Eheim experience 150, sponge and Sera siporax

5. Lighting and duration.
4x 24W T5, starts on 8am at 30% with two lamps ramping up after one hour to 100% with two lamps, mid day 5 hours full power with 4 lamps. Then switching back to two lamps 100% ramping down to 30% at 11pm switching off.

6. Substrate.
Inert black painted quartz gravel

7. Co2 dosing or Non-dosing.
CO2 dosing with tank internal JBL taifun diffuser.

8. Drop Checker.
Yes green, not really lime green

9. Fertilizers used + Ratios.
KNO3, KH2PO4, MgSO4, KSO4, CSM+B (optional DTPA)
Last water change 65 liter added
15 ml MgSO4, 7.5 ml KSO4, 1/64 tsp KH2PO4, 1/64 tsp CSM +1/64 tsp DTPA. No KNO3 try to keep NO3 low.

10. Water change regime and composition.
65 liters weekly, see attachment for water analysis.

11. Plant list + Invitro/Emersed.
Crypto's, hygrophyla polysperma, anubias, hydrocotyle, elodea densa
All longer than a year in tank.

12. Inhabitants.
some platys, 3 oto's, 3 small siamese algea eaters, 1 ancistrus, 4 Trigonostigma heteromorpha, lots of small snails.

13. Full tank shot and surface image.
See pictures.

Hope someone can help me with this issue.

 

[Midwife]

I found with this plant it prefers cooler water in a non flow area. Fish like to eat it also.

 

[G H Nelson]

This looks like high lighting reaction!
Similar to Blyxa japonica under intense lighting.....so not a deficiency, as others have mentioned likes lower temperatures.

 

[dw1305]

Hi all,
It looks all right, I think @GHNelson may be right.

7. Co2 dosing or Non-dosing.
CO2 dosing with tank internal JBL taifun diffuser.

8. Drop Checker.
Yes green, not really lime green

9. Fertilizers used + Ratios.
KNO3, KH2PO4, MgSO4, KSO4, CSM+B (optional DTPA)
Last water change 65 liter added
15 ml MgSO4, 7.5 ml KSO4, 1/64 tsp KH2PO4, 1/64 tsp CSM +1/64 tsp DTPA. No KNO3 try to keep NO3 low.

It looks like a deficiency symptom on the Hydrocotyle. Plants can only make use of the added CO2 if other <"nutrients aren't deficient">.

It is very likely to be nitrogen (N), purely because that is the macronutrients you aren't dosing. Add some fixed nitrogen and you should get <"fairly instant greening">.

I'd just ignore what you read on other forums etc <"about nitrate (NO3-)">, it is mainly <"written by people"> who don't really understand what they are talking about. Have a look at <"What is the “Duckweed Index” all about?"> and subsequent posts.

cheers Darrel

 

[Sanniejop]

I found with this plant it prefers cooler water in a non flow area. Fish like to eat it also.

Hello Midwife, thanks for your reply. Which temperature range do you think it should be? It is now around 23-24 'C.

 

[Sanniejop]

To GHNelson and Darrel,
First of all thanks for your replies.

I also experimented with higher no3 levels (30ppm) but this did not help for the hydrocotyle.

Since it looks like there are stems that are doing wel and some not (those who are not are closer to light source) i though it could also be a co2 deficiency? Plants recieving more light want to grow faster so have a higher co2 demand? Also the leaves are turning very pale. And also the very new grown leaves are initially green. So i thought it could not be a salt nutrient dificiency?
Could that be right?

To test this i did several things (i know to much simultanously but all for the same reason) I increased co2 a little bit, switch co2 one hour earlier on before the lights go on. And cut the duration of 100% light intensity with 20%.

Also,
I cutted the most problematic stem down and planted it a bit lower. New growth (or young leaves which were showing discoloring) seem to be instantanously green again. See pictures
At the same time other stems reaching the surface are stunting. Others are doing fine.

See forward to your opinion
Thanks for your help,
Greetings Sandor

 

[G H Nelson]

Hi
6. Substrate......Inert black painted quartz gravel.
I would add root tablets/balls/sticks to improve plant root development!
Purchase a TDS Meter/Pen....and check TDS is not too high!

 

[dw1305]

Hi all,

And also the very new grown leaves are initially green. So i thought it could not be a salt nutrient dificiency?
Could that be right?

It is one of the mobile nutrients (plants can move it to new leaves, that is why they are green). Most nutrients are mobile within the plant, which makes diagnosis more difficult.

cheers Darrel