Hygrophilia Polysperma Leaves Drooping

[bobfloyd]

Hi. Here are the details of my tank:

6' (~ 400 litres)
Red Sea CO2 pro system
Eheim 2217 canister
240W tri-phosphor lighting
pH: 6.8
KH: 4 degrees
GH: 13 degrees
Ammonia: 0
Nitrite: 0
Nitrate: ~ 10-15 mg/L
Iron: ~ 0.25 - 0.5 mg/L

I have various plants in the tank. Most of the plants appear to be doing quite well with the exception, strangely, of the hygrophilia polysperma!! For some reason, the leaves on this plant are drooping downwards and the stems are rotting! The same thing started to happen to some H. Stricta (both Hygrophilias). I have had this happen with pre-existing plants, so I bought some more, and the same thing has started happening to them.

I started off by dosing with Aquasonic Basic Grow and dosed Aquasonic Daily Grow every day at the instructed rate.

I know that Hygro is an excellent indicator plant - what on earth could be wrong? Has anybody seen this before?

I have just done a couple of large water changes in a row and I am holding back on the fertiliser in case there is something dodgy about it.

 

[bobfloyd]

Any ideas?

 

[Themuleous]

What fert system are you using? Also, do you know your co2 levels?

Sam

 

[Colin_T]

The water seems fine and Hygros are usually pretty tough. If the plants are new then they might have been damaged during transit. Or if you have been pruning them recently they might have suffered some serious damage.

 

[bobfloyd]

What fert system are you using? Also, do you know your co2 levels?

Sam

I am using Aquasonic Basic Gro/Daily Gro. Also, 100% Seachem Flourite substrate.

CO2 levels are around 20ppm.

 

[bobfloyd]

Could this be what they refer to as 'Biogenic Decalcification'? Is there where some plants do well and others don't?

 

[bobfloyd]

I notice that if I take a cutting of hygro, i.e. snip the top off a growing portion, strip the lower leaves and plant the cutting, the leaves droop and the plant starts to rot.

Any ideas as to why this could be?