What causes old leaves to go a brown colour?

[TomMessenger]

I've found recently that stem plants in particular aren't as green below the first couple of nodes. The same thing for my Hydrocotyle too, but that seems to be mainly just round the edges of each leaf. The new leaves are nice and bright green in both cases, but the older leaves are a browny-green colour. It's not diatoms.

Is this down to a deficiency? It's happening in both my tanks at the moment, but here's the specs for one:

ADA Mini M
18w Compact T5 6" above tank
ADA Amazonia
ADA Brighty K and Step 1 - 1 pump each
Spezial N - 2ml (4ppm NO3)
Flowgrow - 2ml
KPO4 - 0.4ppm
MgSO4 (forgotten actual level, but worked it out with an EI dosing calculator!!)
CO2 at 1.5bps + 2ml Excel

Anyone got any thoughts?

 

[Crispino Ramos]

Trim the old leaf of the H. verticillata - it will encourage new leaves. You can also trim your stem plants, replant the tops and toss the old bottom stem in your compost pile. The replanted tops would grow faster accustomed to the tank environment.

 

[TomMessenger]

Thanks Crispino - All the old Hydrocotyle leaves have been trimmed, and everything there now has been grown in the tank. It's sibthorpioides by the way, not verticillata. The stems have already been replanted as of last week. Brand new leaves seem fine, but as soon as another sprouts, the older one goes brown around the edges, and it gradually covers the leaf. I'm seeing it in pretty much every plant I have, and have the same issue in the Do!aqua cube which has a similar fert regime minus the ADA products.


Here's a couple of examples:

Now, James' Planted Tank says that brown old leaf edges could be a Molybdenum issue or darker leaves could be Phosphates. I'm dosing 0.5ppm P or thereabouts plus 0.4ml TPN+ now, along with Flowgrow and Step 1 which both presumably both contain Mo (Yes I'm going for overkill and throwing every bottle I have at it out of desperation - things have improved, so something in there has worked)

Cheers,
Tom

 

[dutchy]

Your dosing regime is on the lean side (4 ppm NO3, 0,4 ppm PO4) and could be cause of a deficiency. It's easy to rule this out by adding more of...everything. If this doesn't resolve the issues, try adding more CO2 and stop adding Excel.

 

[Crispino Ramos]

It looks like an algae issue - a case of diatoms. I looked closely on the picture and I could see that it's more pronounced around the edges of the leaves but it's also sprinkled all over the plant. Here's an article of diatoms, it might help.

http://www.aquaticcommunity.com/aquariumforum/showthread.php?t=60144

Search this site for discussion about diatoms also.

 

[TomMessenger]

Thanks for the link Crispino - I would have assumed that diatoms would wipe off the leaves though? Whatever this is doesn't wipe off. I did get diatoms earlier in the setup, but they cleared pretty well and everything looked perfect. Shortly after that, I messing something up somewhere and ended up with Spiro, Rhizo, BBA and Staghorn. The Rhizo and Spiro have now all but gone, and I'm left with whatever this is (and old BBA and stag, but it's not spreading now).

Dutchy - so if I just add more TPN+ on top of what I am already dosing and see what happens? I started with just Amazonia substrate, Brighty K and Step 1, but was offered Spezial N and Flowgrow to try when my HC was struggling after fill-up (I did a dry start). Then I already had the liquid carbon so started dosing as a precautionary measure. During the algae problems, it was suggested that I try adding some MgSO4 and check for any improvements in growth. Then KPO4 when I started seeing a tiny bit of GSA (but was probably CO2-related like the rest of it). The TPN+ was started recently when it was suggested to raise the levels of everything like you say. I have quite a bit of it still spare from a competition I won in 2007 so thought I might as well use that.


Tom

 

[dutchy]

The problem is that I always see a lot of posts about this deficiency, that deficiency. My plants never have deficiencies (unless I make mistakes) because I add full EI and plants have unlimited nutrition. That way it's very easy to rule out that part. So if something is wrong, I already know that I have to look in the CO2 department. That makes it a lot easier.

if you have GSA that is typically a low PO4 issue, although CO2 could play a role, which is, IMO, part of the problem.

Dose more to reach 20 ppm of NO3, 2 ppm of PO4, and double the amount of Fe and traces. It will save you a lot of time. Then try to add more CO2, do it slowly, take some time and keep watching the plants.

 

[TomMessenger]

KNO3 now on order - I have the rest.

 

[Robert H]

Tom, have you found sibthorpioides to otherwise be a problem? My experience was it never seemed to last more than a couple months submersed. Each time I tried it would eventually disintergrate. I came to the conclusion it just was not a good submersible. If thats not the case for you I wonder what you are doing differently

 

[TomMessenger]

I've only had it about a month - I'm also growing it emersed in high humidity as well as in a bonsai pot on my windowsill. It's growing quickly in all 3 places so far. This brown colour on all the plants is the only problem I've seen with it so far.

 

[Tom Barr]

Tom, have you found sibthorpioides to otherwise be a problem? My experience was it never seemed to last more than a couple months submersed. Each time I tried it would eventually disintergrate. I came to the conclusion it just was not a good submersible. If thats not the case for you I wonder what you are doing differently

It grows very well, I have not used it in some 7-8 years but SFBAAPS, AFA etc, they have long running nice examples.
I see no issues with it, it's not as easy as say the reg pennywort, but.........it was not a hard plant to grow for me.

But........I say this about all plants.

I see brown diatoms on the plant leaves, newer tank, some otto cats, gold nuggets etc, very good at diatoms.
The leaves themselves do not look to be in poor shape though.

Trimming is fine, but for many of these species, lots of work.
Let the catfish do the work I say.

 

[Crispino Ramos]

It looks powdery all over the plant and on the tank's glass.

 

[TomMessenger]

Thanks Tom. Well as I say I'm starting EI whenever my KNO3 comes which will really rack up the nutrient levels. Then either way if it is diatoms or a nutrient issue it should sort itself out before long.

I did have a couple of Otos, but they didn't fare so well when I had to do a blackout a few weeks back (CO2 was off, yes!). I'll get a couple more next time I go. The Amanos are doing a great job with the remains of the other algae, but have an unfortunate habit of going for a walk along my floor at night.

Cheers