The Planted Tank Forum banner
1 - 20 of 24 Posts

·
Registered
Joined
·
2,064 Posts
Discussion Starter · #1 · (Edited)
Like the cook who can't boil water, I can't grow Hygrophila polysperma Rosanervig. It never took off in a high tech environment, growing slowly and not spreading out. In a lower light tank, it forms new, closely-spaced nodes but doesn't really take off either. Many of the leaves have small holes inside the leaf and sections of the edges are missing as if munched. In this tank the plant seems to have a yellowish cast, although that could be the light itself.

Water params: 7.5 pH; 150 ppm GH, 120 ppm KH.

Tank 1: variable medium-high light, EI dosed, CO2 injected, 2 ml additional iron dosed 3x weekly. GH Booster not in use.

Tank 2: low-medium light (micromols unknown), Excel 2x/week, lightly fed RCS tank. EI variant dosing is 1/16 tsp KNO3, 1/32 tsp KH2PO4, 1 ml Fe 2x weekly; 1/32 tsp CSM+B or Flourish equivalent 2x week. I had been adding 1/32 tsp K2SO4 2x/week but have switched to 2 ml liquid potassium 2x/week.

Hygro Tiger grows well in Tank 1 but is similar to the Rosanervig in Tank 2. In Tank 1 it occasionally showed leaf edge damage, which I suspected was caused by mystery snails or tiny ramshorns at the time.

Theory 1 - Ca deficiency in both tanks. I don't know what the ratio of Ca to Mg is here but I understand Ca deficiency is relatively rare. Also the stems are not twisted nor are the leaves cupped.

Theory 2 - Insufficient lighting. Both tanks' lights come on in the early afternoon and run for 8 hours. Could indirect ambient light be enough to engage the plants' photoreceptors early, forcing them to shut down before the artificial photoperiod completes?

These are supposed to be notoriously fast growing, invasive weeds but I'm not seeing it. What's going on?
 

·
Registered
Joined
·
8 Posts
I have just joined as I have a similar problem. My polysperma has only once had what I would call a growth spurt. It has the pin holes in the leaves also but I have been dosing K, N and recently P. I was beginning to wonder also if it could be Ca, Mg issue so I have added some Mg and am waiting to see what happens. I have approx 3 wpg of light and have pressurized co2 at approx 30ppm last time I checked. I also added an extra powerhead for flow. other plants in the tank seem to do ok. The valls seem to grow well although they do tend to go slightly red on the tips near the light and occasionally rot.

As we seem to have a similar problem I thought would join in and ask. maybe we can figure it out... as you say I feel like a cook who can't boil water. Ive got to rush off, but ill think about this more.
 

·
Registered
Joined
·
2,064 Posts
Discussion Starter · #3 ·
Very good point about the vals. Of the two species I have in the high tech tank, it's rare that one more than reaches the surface before detaching. Usually it's around 2"-4" from the tip.

Oddly the crinum thaianum (water onion) plant with similar leaves is unaffected.

Another data point: snails do not survive in that tank. Mystery/apple shells disintegrate quickly; nerites die soon but the shells are still extant, despite having spent significantly more time there in some cases. Could be related to shell thickness.

I don't have enough experience with snails in the low tech tank (#2} to rule out CO2 as the culprit in the high tech one. Another calcium deficiency clue?
 

·
Registered
Joined
·
1,402 Posts
In the higher light tank especially, do not be too quick to rule out CO2 as the culprit. Perhaps you could reduce your lighting a bit, slowly increase your CO2, and see what happens with the plant.
 

·
Registered
Joined
·
2,064 Posts
Discussion Starter · #5 ·
Thanks for the suggestion. The CO2 is as high as I can take it without significant risk of shrimp casualties. I tried the Rosanervig both in the open and shaded by ludwigia - not much difference other than the lower leaves suffered. At that time I believe I was running 4 hours of high light and 4 of medium.
 

·
Registered
Joined
·
1,402 Posts
Oh, shrimp. Right.
Well then if you can't raise the CO2, can you reduce the lighting?

I am suggesting this again since I had a similar problem with Hygros in the past (stunting, huge crater like holes in leaves, cupping) and it did respond to a decrease in lighting. Even a small decrease might help. Anyway, I don't mean to flog the suggestion... good luck!
 

·
Registered
Joined
·
2,064 Posts
Discussion Starter · #7 ·
It's an interesting suggestion. I've since added some high light species like cuphea which I'm trying to develop so it wouldn't be practical just now.

The leaf problems you describe aren't what I'm encountering: pinholes, some leaf edge damage as if nibbled by a dwarf red gourami - not that I've just caught someone helping himself to a stauro salad bar - and no cupping.

I really appreciate the suggestion though.
 

·
Registered
Joined
·
8 Posts
Thought I would include some more details of what ive seen going on in the last month or so. I was thinking that it seems in my case that the fast/moderate growing water column feeders in general (Water Wisteria, Polysperma, Heteranthera zosterifolia (HZ), Pogostemon helferi) have not been doing so well recently. The HZ and Polysperma have always struggled whereas the wisteria was once growing very prolifically although not recently and the Pogostemon hasn’t grown much since I added it to the tank although it looks healthy. The slow growers and root feeders on the other hand (crypts, java fern, valls, dwarf sag) are looking healthy and are growing.
This could be pointing to low levels of something in water column. You mentioned Ca. do you use tap water? I cant see it being a lack of Ca if you do. I use tap water which has 80ppm according to my local water authority. It also contains 10ppm of Mg. I have read that there should be a Ca/Mg ratio of 4:1 which is why I recently started dosing a half tea spoon of Epsom salts to my 24*12*12 inch tank. I have seen in mentioned that if you don’t have Mg then calcium absorption stops. In addition you can have too much K and/or Mg which apparently also stops absorption of Ca as it competes for uptake. I haven’t tried changing the ratio by adding Ca but that might be an option.
Another possibility is that my nitrates are usually in the 5-10 ppm range. What is yours? Maybe this needs to be nearer 20ppm.
Also have you had any algae? I’ve had a touch of blue green (maybe pointing towards lack of nitrates) as well as some green spot (maybe pointing towards a lack of Po4).
I does micros everyday (Brightwells Florinmulti) about 5-10 drops. I am wondering if I should change to Seachem products as I’ve never heard much about Brightwell. I also don’t dose extra iron although my micros do contain some iron and I use iron rich fluorite substrate (which again won’t benefit the stem plants so maybe I should be dosing more iron).
I’m going to try upping the nitrates to near 20ppm, keeping the Mg and po4 dosing going for a while and see what happens in a week or two. If it’s not that I’ll have to consider something else.
Let me know how your experiments go :)
 

·
Registered
Joined
·
2,064 Posts
Discussion Starter · #10 ·
Yes, I'm using tapwater. As to the ratio of Ca to Mg, the local water supplier doesn't have that information. I don't recall the peak nitrates but Tank 1 is dosed per standard EI for a 29g tank and levels in Tank 2 are ~10 ppm just prior to a water change. Nothing notable on the algae front, though I've recently replaced the substrate so I'm waiting and watching.

I don't really know which stems are primarily water column feeders vs. roots. The ludwigia repens rubin, which has a large root system, does very well in the high tech tank, while the echinodorus vesuvius does merely okay (aside from a sudden boom in spinning off smaller plants awhile back). Occasionally I'll find a broken vesuvius leaf but nothing like the vals, which I've mentioned already. Myrio does very well but the limnophila aromatica is growing relatively slowly. Lysimachia nummularia aurea and hottonia do okay; the other stems are too new to evaluate.

In the lower light tank, I've already covered the hygros; lysimachia and myrio do well there.

It's just the hygros and vals, really, which are affected by this mystery deficiency. I've never gotten HC to take but think it's unrelated.

I haven't used root tabs in Tank 1 for several months; never for Tank 2.
 

·
Registered
Joined
·
5,370 Posts
I don't think the micros or CO2 is the critical with this plant, it has recently been outlawed in most states if not by the federal government, if your were in Florida or Texas you could find it growing almost anywhere and up to 6 foot in lenth or better. Viginia now has it and I think we also are getting it here in Maryland.

But it likes high light and other than that it's not a very demanding plant, I would try dosing in a normal fashion along with good CO2 levels but not cranked to the point of fish death (no Excel) and medium high to high light. It also seems to like warm water, so if your water temp is 76 you might want to try 78 to 80 degrees.

Your recent substrate change could be another reason for stunted growth, it's like a new set up.

My vesuvius only does well with root tabs, it's a very slow grower, likes light on the higher side so EI dosing alone won't do much for it in the growth depatment. BTW I use Flourite as a sub with Osmocote 00 gel caps under the root feeders every 3 to 4 months.
 

·
Registered
Joined
·
1,498 Posts
These are supposed to be notoriously fast growing, invasive weeds but I'm not seeing it. What's going on?

Same here, I have 2 different types (5 in all) in my 75 and they are VERY slow growing.
 

·
Registered
Joined
·
2,064 Posts
Discussion Starter · #14 ·
Are you sure you water parameters are correct? PH of 7.5 with relatively hardish water, your snail shells shouldn't be disintegrating the way you say they do. I would try testing the water again.
Within reason, yes. The LFS and several test kits agree that pH = 7.5 or more; two test strip kits used sporadically over nine months consistently report GH 150 ppm and KH 120 ppm. There's a lot of limestone in this area so it's unsurprising.

As for the snails, one of the poor things literally fell into pieces around the time of its death. One day I noticed it motionless in the java fern; the next evening the shell fell apart when I picked it up. Keep in mind this is in a CO2 injected tank.

The snails in the low tech tank have only been there a few weeks.

I don't think the micros or CO2 is the critical with this plant...
But it likes high light and other than that it's not a very demanding plant, I would try dosing in a normal fashion along with good CO2 levels but not cranked to the point of fish death (no Excel) and medium high to high light.
EI + Fe, CO2, variable high light - that's what I'm doing in Tank 1. Still stunted growth.

It also seems to like warm water, so if your water temp is 76 you might want to try 78 to 80 degrees.
You may be on to something there.

Your recent substrate change could be another reason for stunted growth, it's like a new set up.
Could be but the hygro was in the tank 3-4 months prior to the change. FWIW, the change was done in thirds over a two month period with no losses.

Once my last few plants are in place - anyone have a couple stems of myrio tuberculatum to spare? :) - I'm adding the rootmedic tabs I've had for a few months.
 

·
Registered
Joined
·
2,064 Posts
Discussion Starter · #15 ·
I confirmed that the local water board doesn't know the individual levels of Ca and Mg. For several weeks after the snail referenced above died, I added GH Booster to the tank, which should have raised both levels. There was no appreciable change in the Rosanervig growth.

Checked several sites; all agree on the Rosanervig doing well over a temp range from 18-28C.

Which puts me back at square one.

Any other ideas?
 

·
Registered
Joined
·
2,064 Posts
Discussion Starter · #16 ·
I've added root tabs which contain Ca and Mg to both tanks, using 1/3 of the larger with a high concentration of vals as a control. If there's an actual shortage of either mineral, I hope to see some changes within another month.

If the ratio of Ca-Mg is the problem, I don't know how to address that. The local water department doesn't have that information and I'm not aware of any cost-effective ways to find out.

Other possibilities?
 

·
Registered
Joined
·
8 Posts
Ive been dosing everything (N,P,K, Mg, and traces) and still polysperma is stunted. I didnt say before but mine are all cuttings. I decided to up root and replant it as it was beginning to look untidy. In the past the cuttings grew fast most of the time so I dont think this is the reason for slow growth. Everything else in the tank is growing. I cannot figure it out either. Im almost tempted to give up on it and order something else. It actually grew better when I wasnt using pressurised co2 which seems counterintuitive.
 

·
Registered
Joined
·
8 Posts
Sorry Rainer I didnt see your last post. See if theres any improvment in a month and report back. Id like to hear about it. I just put some crypto root tabs in but unfortunately it doesnt say whats in them. i think they are a trace element mix. Today im going to reposition my lighting right over the plants in question. I am also thinking of buy new t5 bulbs as mine are a year old now. It might be a long shot because nothing else seems to be suffering. Anyway hope the ca-mg works.
 

·
Registered
Joined
·
8 Posts
Not sure if you are still checking this post but thought I would update. Basically the polysperma is now looking much healther. The leaves which had holes have all been replaced with healthy ones. I make sure I dose Mg, P at water changes once a week and I dose nitrates every other day along with phosphate. Micros I dose everyday. So problem one overcome. They look MUCH better but they are still stunted. They seem to be growing leaves which are very small. sometimes they have a pale look othertimes not. Have you had any success?
 

·
Registered
Joined
·
2,064 Posts
Discussion Starter · #20 ·
The trial has another week to run but I've seen results from adding the root tabs...but only from the vals, not the hygro. It just sits there.

As a recap, I added Root Medic Complete tabs to 2/3s of the high tech tank and all of the low tech one. All the vals in that area responded favorably; the hygro is in the same area but did not. I can't say if the val deficiency was calcium/magnesium or NPK-related as the tabs contain both.

There were no changes in the low light tank, from which I conclude the deficiency there is in light, not fertilizers.

Next I will try trimming the hygro to stimulate a response.
 
1 - 20 of 24 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top