What kind of deficiency?

[Lukara]

Hi, I have some ludwigia in my aquarium and I have nice reddish leaves, but they have somewhat greenish/yellowish veins. Can anybody shed light on this?

Useful Information:
50 gallon tank
Pressurized CO2
4x40watt (160watts) fluorescent lights
KH 5
PH 6.9
Nitrates 5-10ppm (Aquarium Pharmaceutical's test kit)

Maintenance:
50% weekly water change
1/2 tsp K2SO4 weekly
1/4 KNO3 weekly
2.5 ml Iron 2x week
10ml traces 2x week

[plantbrain]

The cure:

Lower the pH using the CO2 gas to 6.7-6.8 for the entire day length.
Add more KNO3, like 1/2 teaspoon 2x a week at least.

Try this and see.
Consider adding 3x a week KNO3 and traces, I add about 15mls of Flourish 3x a week to a similar tank(has more light also).

Also, add some PO4.
Fleet enema, KH2PO4 or H3PO4 can be used.

The KH2PO4 can be added at around 1/16" or a little over of the KH2PO4 powder.
If using the other 2 sources, try 3 drops 3x a week.

The AP test kit is not very good for NO3 measurement FYI.

Regards,
Tom Barr

[Lukara]

Thank you for the information. The only thing that concerns me is the KNO3. I used to dose KNO3 at 1/4 tsp 2x a week and the result was that my ludwigia leaves turned an almost rusty red burnt kind of color (for lack of a better description). It didn't look normal so I cut back to 1/4 a week only. The result is nice reddish leaves with greenish/yellowish veins. Given this history, should I still attempt what you suggested or do something different?

[plantbrain]

Well, red plants in this genus generally turn _Redder_ when deprived of NO3. When they have even less, they will turn pale/die off some.

Now if you have a good deal of fish and feed often , perhaps have high NO3 in the tap etc, then I could see not adding as much NO3.

But ..........if these issues are not the case, you certainly should add more. You are only adding about 4-5ppm of NO3 per dose of KNO3(gravel/rocks etc included here).

Your tank should be removing this in a day or two...............

Regards,
Tom Barr