Rotala sp Green --what's wrong?

Tsunami,

I have experienced the same thing with Rotala indica, although not as severe. It would only be the ocassoinal stem that did it and I would cut it off. Often one side shoot of a stem would look like yours and another from the same stem would look fine. I have no idea. I will, though, throw in a couple of my own thoughts/observations.

When this started for me I jumped on the Ca bandwagon and got some Kent's liquid calcium. Dose 4-5 mls at the wc(in a 10 gallon, 4.5 watts and CO2) of the Calcium. I have a Gh of 9 so i shoul dalready have enough Ca. I have/had been raising my kH from 2 to 4 with baking soda. I am strongly associating this problem with an Na buildup.

I also was dosing more Flourish/Fe than now, although not nearly the levels you are. Only 1-2 ml every day for me. Maybe you are having a nutrient toxcicity situation? How often are your wc's. I assume 50% once a week. Could this problem be a buildup of some unusual nutrient(vandium or something silly like that)? Since this Rotala is suposedly so easy to grow, this theory could make some sense. Leave it alone and it grows fine, let NO3 climb, P drop and it is fine; start going "high tech" and the plants suffers? Maybe it is more sensitive to higher trace buildup? This does not make much sense though, Shane is dosing both his tanks the same.

Lighting... well one never knows but I had this problem before switchng to 9325k bulbs so....and not now.

K, well I do and always have dosed 10ppm of K2SO4 at the wc.

Well anyway, no answers but maybe some clues. If nothing else, you can just add this to the mix

NO3, double what you are using, I add 1/4 teaspoon/20 gal tank every other day or so for this weed at high light(5.5w/gal).

It does better and grows easier at less light, like most plants. There's more wiggle room with less light. Then you can add less NO3 etc.

If you are having trouble with some of these plants, try more KNO3.

The plants will take it from the water column.
I found this plants to fun but a bit too invasive/fast growing for what I want at the moment but has it's uses certainly. Easy to grow but at high light, it likes good NO3 levels, same can be said for a few other plants.

You folks with all that light might want to add 1.5-2x more KNO3. I think you will find along with weekly 50% water changes that the plants will do quite well that you are having trouble with.

Try it for 2-3 weeks and see for yourself. Instead of adding 1/4 teaspoon 2x a week etc, add it every other day.

Regards,
Tom Barr

How sure are you that NO3 are not the issue?
How sure are you that CO2 is not the issue?
How sure are you that these are constant?

If a plant is growing along fine, then suddenly you stunt it, some species do not recover quickly, some do, some are tolerant.

I think many folks go through a peroid where the levels of CO2 or NO3 dip too low and then the plants need recovery time.
Meanwhile algae will sometimes creep in.

Even if the other plants appear fine, one plant species may find if difficult to start up again.

Plants are fairly tolerant of PO4 limitation. Same can be said for traces and K+.

Ca/Mg somewhat, NO3 and CO2 cause much more impact.
You can always do large water changes and dose with KNO3 to make certain the NO3 is what you think it is and then double check the CO2.

Regards,
Tom Barr

Ok, it's been 5 days since I've increased NO3 levels. There have already been some major changes in the morphology of several plants. My "purple strain" Limnophila aromatica has tranformed from a beautiful lilac color to lime green. My Ludwigia arcuata is now orange. The Rotala sp Nanjenshan has shown signs of new, healthy growth (about an inch so far). On the flip side, the Rotala macrandra 'narrow leaf' grew very large leaves in the beginning of the week but has since begun stunting.

Most importantly, although the internodes and growth rate of the Rotala sp Green have both increased tremendously, the leaves are still small and curved downward like in the photo. Some stems have stunted even more, showing some transparent patches on the newest leaves along with the twisting.

Is Rotala sp Green really so nitrate demanding? My usual nitrate indicators --Micranthemum umbrosum, Hottonia palustris, and Heteranthera zosterifolia --grow very large, lush, deep green leaves in all the conditions I've tried growing Rotala sp Green in.

Rotala sp Nanjenshan is recovering? Still looks yellowish. Then again, all my green plants look yellow under the 9325k bulb.


One of my nutrient indicators. Showing very large foliage.


Rotala sp Green still looks horrendous, although growth has quickened and the plant is shooting out many, many sideshoots.


The entire tank has lost a lot of "sparkle" and seems "dirty." A lot of the bottom portions of the plants show considerably amounts of algae.


Carlos

Carlos,
I'm glad you tried upping the NO3. Keep with it for about 3 weeks and then see what you think.

I'm not 100% certain it's NO3 but it might be the K+ also + NO3.

If you like the lower NO3 colors, you can drop the NO3 down for a couple of day etc and get the "red in" take the photo, show your buddies etc then go back to faster growth.

You can also try limiting the PO4 more so that it slows down the NO3 uptake some and make it easier to maintain a lower level at higher light without bottoming out.
To this same effect, one can do this with less light as well.

This can allow good reds with easier wiggle room with NO3/NH4(fish sources at lower light have a larger % on the total N used by plants).

But I think running at higher NO3 for SOME plants might be needed.
Stunting has always been associated with bottoming out the NO3.
Some plants are more sensitive to it and instead of dying/melting etc, they just stunt and wait till the conditions are better and then start growing again.

Some plants seem to need more NO3 than others, wheat for example prefers NO3, not NH4. Sionme aquatic plants like Crypts can handle very low NO3 while Mic umbrosum may need 5-10x as much to grow well.

But few plants seem stunted by too many nutrients.
Perhpas that was what the whole high K+/Ca thing was all about it.

CO2 and NO3 are the two big players.

Regards,
Tom Barr