MORE questions of light and nutrients!
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MORE questions of light and nutrients!

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MORE questions of light and nutrients!
Old 04-29-2012, 09:43 AM   #1
 
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MORE questions of light and nutrients!

I have a 5 gallon hex tank - specifically:
this one this one
It's a 5 gallon hex, and is 16.8 inches tall. I dose flourish once weekly, but the lighting in this tank is way low - only a single bulb, one of these

It has recently been planted with Pigmy Chain Swords (Echinodorus tenellus), Fanwort (Cabomba caroliniana), Vals (Vallisneria Spiralis), a Marimo ball, and some Java moss. . .

I'm concerned that the lighting in this tank will not be sufficient - most especially for the Vals, which require brighter lighting than the others in there. Is there any other bulb that I can use in this tank to boost the lighting, or do you think just this one will be fine?



Next question. . .
When I initially got started in aquaria, I did the accidental fish-in cycle. At that time I got loads of Hornwort to help soak up the toxins and get the fish through alive. It worked, and I've since used the same batch of Hornwort to cycle a 5 and a 10 gallon tank.

Currently, it is in the 10 gallon tank, which is a standard rectangular tank. I dose once-weekly with flourish, and this tank has TWO of the bulbs that are in the 5. Again, these. All was going well, but now that the tank is cycled, and very lightly stocked, the Hornwort is failing. The leaves are getting brown and brittle and growth has dramatically slowed. I don't think that this is a question of lighting, as Hornwort doesn't need very much to thrive, and the pieces that are floating nearest the light are suffering in the exact same way as those that are weighted.

I *think* it may be a problem with nutrients, since Hornwort is such a fast-growing plant. . . should I be dosing this tank 2x weekly with flourish, or could this be another problem that I'm missing. . .



Last question (for the moment) also concerning the 10 gallon tank. I was sold some Cryptocoryne Spiralis mistakenly - it was supposed to have been Pygmy Chain Sword (Echinodorus tennellus), but the LFS stocked it in the wrong tank. They look similar enough that I didn't notice until I got home and went to plant it. These Crypts are not a plant that I would have chosen for any of my tanks - they get too big and probably need more light than I can give them - and will likely melt anyway (they were just added over the weekend). But if they don't. . . is there anything I can or should do to the lighting in this 10 gallon tank to bring the brightness up for these plants? Or will what I have be sufficient (providing the change of tanks doesn't do 'em in - I know Crypts can be tricky)? Last time... the 10 gallon tank has TWO of these bulbs. . . Also, will root tabs be necessary, or will flourish be enough?



Thanks in advance for any advice/info you guys have to offer - and just for reading through all of that!
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Old 04-29-2012, 10:04 AM   #2
 
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Forgot to add that the lights in both of these tanks are left on for around 10 hours a day. . . this should probably be increased, right? 10 hours seems perfect for my 29 gallon, at the moment - any more in THAT tank and I start to see hair algae forming, so I just kept the same amount of time in all the tanks. With the lower lighting, these could possibly stand 12 hours?

Last edited by Chesh; 04-29-2012 at 10:07 AM..
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Old 04-29-2012, 11:12 AM   #3
 
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From the data on the package in the link, that light might be fine. As for duration, anything above 6 hours minimum is fine provided everything balances. Increasing duration does not compensate for lack of intensity; no matter what the duration, the light intensity must be sufficient to drive photosynthesis. All of this is general and can be variable from tank to tank. What works in one tank may not in another. As you only have one socket, getting a higher wattage bulob to increase theintensity is the only option, if that seems needed.

On the Hornwort, nutrients may be the issue. Increasing Flourish to twice weekly might help. CO2 is the one thing you can't contorl as it just occurs from the fish, pants and organics, but at the surface plants can assimilate CO2 from the air so this is not usually a problem with surface plants.

Crypts are relatively low-light, so no issues there. Most willmelt initially, ust leave the roots alone and the plant should rebound. Sometimes within a few days, sometimes weeks.

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Old 04-29-2012, 12:20 PM   #4
 
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Originally Posted by Byron View Post
Increasing duration does not compensate for lack of intensity; no matter what the duration, the light intensity must be sufficient to drive photosynthesis. All of this is general and can be variable from tank to tank. What works in one tank may not in another. As you only have one socket, getting a higher wattage bulob to increase the intensity is the only option, if that seems needed.
This makes sense to me, though I never really thought of it as such.

In simpler terms so I'm sure I understand: the plant's photosynthesis is directly related to the BRIGHTNESS of the light - NOT the duration. So it can only photosynthesize as much as the brightness of the light allows it to, regardless of any other factor.

If this is the case, what role does the duration of light play? Is it only to allow the plant enough time to absorb and store enough nutrients? I know all tanks are different in this regard, and if the light is allowed to be on longer than the plant requires it will give algae a foothold. . .

For the tank with the Hornwort, nutrients are the only thing that I can think could be lacking. If CO2 is the problem, the floating plants would be fine while the weighted ones would be having the trouble. I'll up the dose to 2x weekly and see what happens there. . .

For the crypts. . . I get a lot of mixed information, both from books and from internet resources and forums! Some say low light, some say moderate to bright! Again, I'll just have to wait and see on this one, but thanks for the reassurance. I know that these will outgrow the tank-space if they DO decide to grow, but we'll cross that bridge when we come to it!

Always, thanks for your input, Bryon!
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Old 04-29-2012, 12:35 PM   #5
 
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It looks like those bulbs have a plastic cover around the fluorescent tube to make them look more like conventional incandescent bulbs, it also looks like that cover is not clear. Can you remove that? I think doing so would allow more light to get to the plants.
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Old 04-29-2012, 01:46 PM   #6
 
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It looks like those bulbs have a plastic cover around the fluorescent tube to make them look more like conventional incandescent bulbs, it also looks like that cover is not clear. Can you remove that? I think doing so would allow more light to get to the plants.
Good point. . . no, it isn't a cover, but the glass does have a whitish coating over it - possibly painted on. Either way, I can't remove it, and I'm sure it does diffuse a bit of the light. *shrug*

If I have to go up in wattage, I'll just have to find another bulb. Hopefully these will suffice for the crypts, they've been good thus far with the other plants, and I can correct the issues in the Hornwort with additional ferts, rather than stronger lighting!

Thanks for the thought! I didn't even THINK of that!
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Old 04-29-2012, 02:31 PM   #7
 
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sounds like those are different than the ones I've seen and thought they were - the typical spiral CFLs with a cover so they can be used where the bulb is exposed without seeing the spiral bulb
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Old 04-29-2012, 03:06 PM   #8
 
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Quote:
In simpler terms so I'm sure I understand: the plant's photosynthesis is directly related to the BRIGHTNESS of the light - NOT the duration. So it can only photosynthesize as much as the brightness of the light allows it to, regardless of any other factor.

If this is the case, what role does the duration of light play? Is it only to allow the plant enough time to absorb and store enough nutrients? I know all tanks are different in this regard, and if the light is allowed to be on longer than the plant requires it will give algae a foothold. . .
Photosynthesis is driven by light, so light that is of sufficient intensity for the particular plant species must be present or photosynthesis will not occur. [Spectrum is also important, I'll come back to this.]Once the light is of sufficient intensity, the plant then needs 17 nutrients in varying proportions to each other. [Briefly, some nutrients can be stored by some plants, some can't, and an excess of some will cause deficiency of another because the excess may affect the plant's ability to assimilate something else.] Provided both requirements are met, being sufficient light and all nutrients, plants will photosynthesize full out, which means to the max. [This is why plants can grow at incredible rates in high-tech systems.] This continues until something is no longer available, at which point the photosynthesis will slow or may stop completely. This factor that slows or stops photosynthesis is termed the limiting factor to growth. A botanist named Sprengel discovered this, but another botanist named Liebig expanded it so it is often termed Liebig's law of minimum.

Light should always be the limiting factor, never some nutrient(s), as this controls algae. In natural planted tanks, using nature rather than gadgetry, carbon (CO2) can often be the first thing to give out. We can control the light, and we can fertilize the other nutrients. But CO2 occurs naturally. This is why one often has to experiment a bit with light duration, to make sure the duration does not exceed the available CO2. IF this occurs, algae will take advantage, because it is able to find nutrients from many sources that plants may have difficulty with. So we tend to limit duration.

Duration is also of importance for the plants to photosynthesize. It is now considered that six hours of good light is the minimum for good plant growth. But as I noted previously, if the light is too weak to drive photosynthesis for the plant species, extending the duration will not compensate. But algae will be rampant.

Darkness is also essential to plants, just as it is to animals. It is the necessary rest period when the physiology can recharge itself. |So this must be factored into the duration too. Most sources suggest a minimum of 8 hours of complete darkness during each 24-hour period. This also benefits the fish, which is why "moon lights" and such should never be kept on all night. Darkness with no ambient room light is essential.

Last word on spectrum. Intensity is clearly the more important of the two, and if the intensity is high no matter what the colour, within reason, plants will photosynthesize. But for those of us wanting to limit the intensity for the sake of the fish, the spectrum becomes more important. Plants need red (primarily) and blue to photosynthesize, so providing peaks in these two colours should be helpful. Adding green/yellow helps prevent the blue/red from casting a purplish or ghoulish hue which distorts colours of fish, plants and everything else in the tank. This is where Kelvin enters the equation, as this is the measurement of the colour temperature of light. The spectrum is related but not the same as Kelvin.

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Old 04-29-2012, 03:35 PM   #9
 
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Originally Posted by Quantum View Post
sounds like those are different than the ones I've seen and thought they were - the typical spiral CFLs with a cover so they can be used where the bulb is exposed without seeing the spiral bulb
I think you're right, Quantum. These aren't those.

I was unable to use the 'standard' spiral lights to fit these tanks - you actually helped me out on this one on another thread, I think! You reccomended the Zoo Med Ultra Sun . . . the problem with BOTH of these bulbs was that the . . . I think it's called the electronic ballast?. . . the white chunky part at the bottom was too wide to allow the bulbs to fit properly - the metal part was sized fine. So I ended up with these.

I'm really thinking that this IS a problem with nutrients, rather than lighting - but it's really good to know all of this stuff, regardless, for any issues that I may happen upon in the future!

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Old 04-29-2012, 04:33 PM   #10
 
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Thanks, Byron... all of this makes sense, and much of it I understand from reading other sources as well as the articles you've posted on this sight.

I intend to keep all of my tanks low tech, and judging by the health of the other plants, I think that lighting is NOT the problem here. Nor CO2, though that might become an issue in the future, but we'll work that out when and if we come to it. . . for now, all of the other plants are all growing well, there is no problem with algae. . . I think I *might* have accidentally managed to do it right the first time (with your help, and the help of others). When I come on here with an OMG I KILLED THEM ALL thread, you can laugh at me for saying this

All of the other plants in the other tanks are doing well, except for the Hornwort, which is possibly the 'greediest' nutrient hog out of the lot, judging by how quickly it grows, which really has me leaning toward this being a nutrient issue. . . I'm going to test this by leaving the lighting as-is, at 10 hours a day, with the bulbs that I have already gotten with your help, and dosing the flourish twice a week. If that doesn't work, we'll try something else. I honestly don't even care about the hornwort at this point, it's done it's job and kept my fishy friends well through the cycle, now it's a bit of a messy nuisance - but I don't want to kill it, plants are people too! And it will do it's job well in the QT tank where stocking levels will change.

This brings me to another question of nutrients. . . I use the Seachem Flourish (again, on your recommendation ) in all of my planted tanks. They are ALL lightly stocked, however. I've been reading regarding the types of nutrients that the plants need, and I've a question relating to this that I'd love some clarification on. . .

IF I understand correctly, plants need a source of macro nutrients (which are produced by fish wastes) and micro/trace nutrients (provided by the Flourish). My tanks are ALL very lightly stocked right now. And the 10g is going to remain that way, as new fish are QT'd there before moving onto the other tank. Is it possible that my plants could not be receiving enough of the macro nutrients, due to the low stocking levels? THUS FAR it has not been a problem, again, only the Hornwort is affected in any way. EVERYTHING else is thriving. But I would like to know more about this for future reference.

A related question is this: I've been told by several people on this forum that you recommend NOT vacuuming the SURFACE of the substrate in a planted tank during weekly water changes. Are you being mis-quoted? And if not - why do you recommend this? It seems very contrary to everything I've learned about fishkeeping to date!

My tanks have a substrate purely of Tahitian Moon Sand, from 2 - 4 inches in depth. I have a small and thriving MTS population to help aerate the sand bed, and I know that the plants release oxygen through their roots that will help keep the sand from forming anaerobic pockets. I also am aware that they will take nutrients from what wastes do get trapped around the root systems. I do, every month or two, sift the sand in the area that is NOT densely planted (a large area of my tank has no plants), and I vacuum up the debris from fish/food/plant wastes during my weekly water changes. I've been taught, from a FISH KEEPING point of view that this is very important to do. . . and I own and have read Peter Hiscock's Encyclopedia of Aquarium Plants - he also recommends a regular vacuuming of wastes from the surface of the substrate.

I just want to check with you on this . . . I know you put the fish first in all things, and it seems like you may be getting misquoted. If not. . . please clarify!??

And FINALLY. . . ONE MORE QUESTION on nutrients. . .

In my seemingly thriving 29 gallon fully planted tank my nitrates are at 0.It's a new setup still, but when I learned about the Nitrogen Cycle, I put in a HUGE amount of floating hornwort, along with Java Fern and Anacharis, to help keep the fish safe through the cycling. I tested daily through the cycle, and really up until the last week or so. Monitored the nitrate through it's initial spike, and watched as the numbers slowly fell to zero. When I actually planted the tank as it is today (several weeks ago now) there was a short period when the numbers rose slightly, and then fell back again. The other 2 planted tanks have a No3 reading of 5 and 7.5, respectively, and are far less densely planted than my main 29 gallon tank (you've seen it here).

From my limited newbie understanding, this is AWESOME, and shows that my tank is currently in perfect balance between stocking and planting. . . the plants are thriving, growth is seen daily, and I have many daughter plants in this tank in a very short time. However, some have told me that it's NOT a good thing, and that I have to/should be sure to keep nitrates in the tank (even if I have to ADD them by some other means) in order to keep the plant-life healthy. I'm a bit baffled by this, as the plants are growing so well! Can you (or anyone else reading this!) offer me some clarification here? I'm a bit confused . . .

If you got through all of that - a MILLION thanks to you! I'll be eagerly awaiting any enlightenment anyone can bring me!
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