Plant Issues - Stem & Sag
Four weeks ago I started a 30 gallon (36" footprint) as grow out tank for 15 very young Juvie A. Cacatuoides fry.
The substrrate is Tahitian Moon Sand
Dosing with Comprehensive twice a week and Seachem root tabs.
Initially I installed a single tube T8 32 Watt Grolux bulb – I do not know the K rating (it came with a used fixture).
Lights are on for 10 hours per day.
Temp is 75 degrees
Hard water with a 7.6 ph.
Ammonia 0 – Nitrites 0 – Nitrates 10 or less and several readings with 0
Hygrophila pinnatifidia (I love this species)
With the Grolux
Crypts – grew great
Pinnatifidia – grew great
Java's – grew great
Stem Plants – grew great on TOPS – seemed to rot & melt at base of stem above substrate
Sag – did horrible, all plants experienced yellowing of leaves on ends and then melt. 3 of the sags melted away.
Thinking I might have a light issue, a week and half ago I added another 25 watt 6500K T8 Zoo Med Ultra Sun
This gave me 57 watts of light between the two lamps.
Even with the additional light I am seeing the same conditions, except now some of the Crypts are experiencing the yellow leaves.
Do my plant symptoms appear to be a lack of Nitrogen?
What do you think I need to do?
I have another planted tank with low light levels, minimal dosing and low light level plants which has been doing great, but I've always struggled with stem plants.
To me it sounds like when my plants aren't getting enough light. I'm hardly an expert at figuring out plant symptoms though. The total lack of nitrates could certainly be a problem. Is it all of the stems doing that, even the Rotala? Are you giving root tabs to the sag?
BTW I'm jealous that you both own Crypt nurii and can get Hygrophila pinnatifidia to grow well. I've had success with a number of different plants, even some that are harder to keep, but never with the pinnatifidia.
Yes, I did provide root tabs to the Sags.
I am praying the Pinnatifidia continues to prosper, it is a beautiful plant and one of my favorites.
In my experience, the "grow light" and other plant bulbs are heavy in the red spectrum and actually provide less PAR (photosynthetically active radiation) than the "Daylight" full spectrum bulbs. I'd first suggest changing the bulb.
Dwarf Sag will occasionally fail if moved form a high-light environment to a very low light one. But dwarf sag does ok in low light for me. I'd also say look very carefully at how you planted the dwarf Sag. Never bury the leaves or root crown, the plant will die if it's planted too deep. Easy to say, but hard to plant the dwarf sag correctly sometimes.
With your lighting, I'm just not positive the stem plants will thrive. They are more picky regarding light intensity and require higher intensity to do well. That's why the tops are doing well = closer to the light.
Try floating small portions of each stem plant on the surface. If your floating stem plants do ok and the rooted ones slowly fail, then it's the light, not a nutrient issue.
Interestingly, I have a couple of crypts and have, to date, never experienced "crypt melt" yet.
I agree with what's been posted. The crypt issue is the light change, leave the roots (siphon out the mushy leaves during the water change) and they will recover.
Stem plants generally need more light than rooted plants. The lower leaves dying off is common unless the light is quite bright. All species of Hygrophila are prone to this.
The Grolux-type tubes are less intense light than daylight, part of this is undoubtedly the green-yellow light and this is more important to aquarium plants than some of us might think. I happened to post on this very issue only yesterday, so here is that copied over; this is a citation from Diana Walstad's book where she is commenting on the results of the study that determined plants grow best under what we now call "daylight" tubes.
The fact that plants did very well with Cool-white, which produces mostly green-yellow light was an unexpected result of this study. One would have expected the plants to do better with Vita-Lite [this was the "full spectrum" tube used in the study]. This is because Vita-Light was designed for growing plants; its spectrum, which is rich in red and blue light, matches the light absorption of plant chlorophyll much better than Cool-white and many other fluorescent bulbs.Here again we have the 6500K "daylight" mix that all agree works so well; red, blue and green-yellow. Changing to one of these tubes will probably help.
To expand up on Byron's information regarding photosynthesis. It's important to understand that different plant pigments absorb light differently. Note that a significant absorption of energy is from the "blue" portion of the spectrum. In this case, the higher the peak the better. Daylight bubs most often come closest to matching this using a single light tube. Simply put, you get more energy delivered (PAR) for photosynthesis from a Daylight tube than a red-spectrum "plant" bulb.
I think the replies are excellent and point me toward the direction of replacing the Grolux, which I did today.
I purchased a 6500K Daylight Deluxe Bulb (2 pack) from Home Depot - $9.00 for the pair.
No question I had the sag too deep in the substrate so I moved it up where the root crown is at the surface.
It was interesting to read that the sag might have experienced issues coming from a high tech to low light envirnoment as this was excatly the case. Most, but not all, of these plants came from a club brother and a very high light, heavy fertilization, CO2 tank.
The spectrum chart is super, thanks!
I've been reading a lot of Tom Barr's opinions lately, and he really doesn't seem to buy into the "MORE LIGHT!" train of thought, and instead argues that co2 is key.
I don't use co2, nor do I plan on it. However, I do feel that nutrients are probably the problem. I think the fact that your other plants are doing well proves nutrients are the problem.
In short, I think you need more macro-nutrients. Flourish, although it has everything, is pretty low on the macros (especially Nitrogen, Potassium, and Phosphorus).
I use soil in my tanks, but I feed varying amounts. I've noticed when I feed less, the rooted plants (dwarf sag, crypts, and swords) are the first to suffer. My theory is that the root feeders absorb nutrients more slowly, and the stem plants suck them up before they can pass through the substrate to the plants roots.
Are your crypts melting or yellowing? I've had my crypts yellow but remain firm- this is not "crypt melt". I would either feed your fish slightly more (what they can consume in 2-3 minutes, but one more time per day, or else look up some "Osmocote Plus Aquarium Root Tabs". They're homemade, and look funky, but contain more NPK and have been used by a lot of hobbiests.
However as suggested by the forum members who posted, I also felt that I needed to boost my lighting. Most of what I read indicated 2.0 watts per gallon was kinda the basic minimum to meet most of the needs on lower end plants without the need for CO2. At this point that's what I have 2.0 watts per gallon with fresh bulbs.
When I installed my crypts for the first time, they all melted away, but all of sudden they sprang back.
The only yellowing to the crypts occurred when I added the second light.
Are you using just root tabs?
Do you feed your plants Macro specific ferts? If so, what type - dry or a liquid form?
Another item I am curious about: this is 1 of 7 tanks I keep, my other tanks generally carry 10-20 ppm Nitrate. This tank is carrying 10 or less and on several readings is 0. Is this in an indication of potential Nitrogen deficiency or is it unrelated to nutrient anaylsis.
Might would expect the symptom's from plant's moved from high light,CO2 injected tank. Much like plant's going from emmersed state to submerged.
Would were it me,,reduce lighting to eight hour's a day for a few week's and continue with flourish comprehensive twice a week and maybe a pinch of dry fertz KNO3,KH2PO4 once a week.
Believe at this point,,it may be lack of CO2 that is hampering the plant's.
Is said that plant's can and do adjust to low level's of CO2 like which that occur's naturally in the tank so maybe just a waiting game.
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