Anubias growth dying, rest of tank thriving

[TXaggie]

Hi! I'm a little stumped as to what's wrong with my Anubias plants. I have a low tech lightly planted 29 g tropical aquarium.
Lighting - single T5 18watt
No CO2, flourish excel added kinda randomly
Root tab like fertilizer applied to appropriate plants, flourish comprehensive dosed weekly to water
Plants: crypt wendetti, val corkscrew and regular, Christmas moss, crypt parva (not doing well, shaded by driftwood) and two anubias plants that I can't remember the variety for.

Everything is thriving except the anubias, they send out new growth that often yellows or browns and dies off. Sometimes only half the leaf, which seems weird. But the crypts are doing great, and the vals seem fine although they occasionally loose some leaves. I recently trimmed the moss because it was attempting to take over.

I understand a lot of things can cause this, but I'm surprised its only those plants (I got them because I thought they were idiot proof!) and none of the others. Any ideas??

 

[aqua_chem]

Do you have a nitrate test kit? Can you check that and report it?

 

[Rivercats]

The leaf on the 2nd picture that you can clearly see dark veins and lighter leaf tissue looks like magnesium deficiency to me. And what your describing sounds like nitrogen (nitrates) or perhaps phosphate deficiency.

 

[aqua_chem]

Agreed, but nitrate is by far the easiest to rule out. Do you have a GH kit by chance?

 

[TXaggie]

Hi aqua_chem and Rivercats, thanks for replying.

I used my API test kit tonight and these are my params currently:

Ammonia - 0.25
Nitrite - 0
Nitrate - 5.0
pH - 7.6

I did a 10% (3 gal) water change on Sunday, and a 20% change the week before that. I usually change the water every other week or so, only 20% at a time.

Should have included the tank stock too, here it is:
6 longfin danios
8 neon tetras
2 longfin whitecloud minnows
1 honey gourami
4 cory pygmaeus/habrosus mix
2 mystery snail

I just find it so weird that most of my plants seem to be doing fairly well! But the dark green veins and lighter edges is common among most of my plants in the tank except the Vals.

Thinking back, I'm sure I was slack dosing ferts for a month or two in Dec/Jan - I had twin girls so I feel I have some excuse for neglecting my tank a bit.

But I will say the problem has been going on longer than a few months, it's just gotten much worse recently.

 

[aqua_chem]

Your low nitrate might be playing a part, but I also notice that you're not using any liquid ferts. Your other plants are getting micronutrients from root tabs, but the anubias isn't getting any, which might explain why it's not doing as well.

 

[TXaggie]

Your low nitrate might be playing a part, but I also notice that you're not using any liquid ferts.

Well, I do dose Flourish complete about weekly. As I was saying above, I think I was pretty slack on it for a few months but it's been some time and I've been dosing it more regularly.

How do you correct low nitrate? I guess I didn't realize that would be an issue for the plants, I always thought keeping it as low as possible was better for the fauna.

 

[aqua_chem]

Is the new growth also like that?

Correcting nitrate is just like correcting anything else - you dose something that contains it. Seachem makes a nitrogen fertilizer, or you can do dry ferts. I think you best bet at this point is to keep dosing flourish, maybe more than is recommended on the bottle.

Do you know how hard you water is by chance?

 

[TXaggie]

It is actually mostly the new growth that seems affected.

Oh right, just add nitrogen not necessarily nitrates. Sorry, my brains not firing on all cylinders. I'll recheck how much of the Flourish I'm dosing and maybe start dosing more often.

I'm not sure about the hardness here, but most Texas water is pretty hard and our area falls somewhere in that category. I only know that it's hardness is enough to keep me from having almost all of the smaller tetras due to their need for softer water.

Thanks for all the help!