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MORE questions of light and nutrients!

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MORE questions of light and nutrients!
Old 04-29-2012, 07:26 PM   #11
 
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There is a lot of differing opinions on many aspects of the hobby, which is fine; but there is also a lot of misinformation that some do believe is fact, and this is not fine. One must also remember that well planted tanks operate rather differently from non-plant tanks.

Plants need 17 nutrients. All of these--except for hydrogen, oxygen and carbon--are included in Flourish Comprehensive Supplement, so using it is in fact adding (most) macro- and all micro-nutrients. The level of macro nutrients is not great because Flourish Comp is intended as a "supplement" like the name suggests. And there are two main natural sources of nutrients. Water changes and fish food. In most regions the tap water (source water for aquaria) is medium hard or harder, so this takes care of two of the macros--calcium and magnesium--which are also present in fish foods, so these are present but minimally in Flourish. Carbon occurs as CO2, hydrogen is water, and oxygen is not going to be lacking. The only other macro is nitrogen, and there is likely going to be plenty of that as ammonia/ammonium which is the form of nitrogen most aquarium plants prefer. Fish release ammonia in respiration, and it also occurs in the breakdown of organics as I'll come to momentarily. Those of us with very soft source water need additional calcium and magnesium because the amount in Flourish Comp is insufficient on its own.

The micros are all in Flourish, and these also occur in fish foods. Which brings us back to the organics. All foods digested by fish end up as waste, and this along with any decomposing plant matter settles into the substrate as organics. Here various types of bacteria break it down, releasing a lot of CO2--more than the fish and plants release by far--along with ammonia, nitrite perhaps, and nitrate. This has nothing to do with the nitrifying bacteria. Some of the substrate bacteria feed on nitrates for their energy. Some of the nitrates produced end up as nitrogen gas and escape into the air, completing the cycle. During this breakdown of organics, all sorts of nutrients are made available to plants. It is possible to have a healthy aquarium balanced with fish/plants that is as close to self-sustaining as it is possible to be. This is risky however, since we are dealing here with a closed and thus un-natural system, and expecting it to function as nature. This is not possible. So we assist it along the way with water changes, fish foods, and usually liquid plant fertilizer.

So leaving the substrate alone allows the greatest possible natural interaction. And no, I do not vacuum my substrates generally. This would only be depriving the tank of much-needed CO2. I have a couple of tanks where I may do some periodic cleaning on the surface, always in response to issues. There are many aquarists who recommend not cleaning the substrate even in non-plant tanks, due to the complex bacteria system. It is actually necessary to have some anaerobic areas in order to have a complete system. You can read a bit more on this in my article on bacteria:
http://www.tropicalfishkeeping.com/f...quarium-74891/

I have had a spare plant tank running for many months, with no fish, just plants (and snails). I use Flourish Comp once weekly, and do a minimal water change every couple of weeks or so. The plants which are the same species as in my main tanks, manage OK but with reduced growth by comparison. However, the more difficult high-requirement plants wold probably not last at all in such a setup.

On the nitrates. I see no sense at all in adding nitrates to a tank with fish, unless one wants to stress them out. Nitrates should be as close to zero as possible in any freshwater aquarium for the best health of the fish. Fortunately, planted tanks receiving regular substantial water changes will normally never have an issue with nitrates. As I mention above, they occur in the substrate and some bacteria deal with them, others return to nitrogen gas and dissipate into the air. This is a different process from the more commonly understood one involving Nitrosomonas and Nitrospira bacteria.

Byron.

Last edited by Byron; 04-29-2012 at 07:29 PM..
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Old 04-30-2012, 11:34 AM   #12
 
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What are your nitrates?
Some plants do poorly with nitrates below 20 or so... Sure, the lower the nitrates, the healthier the fish will be, but they surely have some immunity to low nitrates. (After all, the natural waterways where fish come from often have traces, 5-15)

As an experiment, (I think Hornwort is a Nitrogen hog, so it's great for cycling.. but doesn't get enough when other plants get well grown), try feeding the fish a little more and see if the growth of all your plants improves.

Ramp up slowly to the bacteria can catch up and there's no free ammonia, but I think it would solve your hornwort problem.

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Old 04-30-2012, 12:06 PM   #13
 
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Some plants do poorly with nitrates below 20 or so... Sure, the lower the nitrates, the healthier the fish will be, but they surely have some immunity to low nitrates. (After all, the natural waterways where fish come from often have traces, 5-15)
Assuming this is ppm (roughly equivalent to mg/liter), it is much higher than the norm. One of the most heavily planted rivers in Amazonia is the Rio Guapore, and the nitrate test in this water was <3 mg/l (ppm). And most rivers in SA have nitrates that are undetectable.

Karen Randall cautioned about dosing with fertilizers containing nitrates, suggesting that the nitrate in an aquarium should not be allowed to exceed 5 ppm at the maximum.

Keeping the nitrates as close to zero as possible will obviously be better for the fish because it lessens the additional work on their physiology. As for plants doing better with higher nitrates, this is rather misleading. A majority of aquarium plants will assimilate nitrate in the absence of sufficient ammonium (ammonia) and convert it back to ammonium in order to use it. No one is going to suggest adding ammonia/ammonium to a fish tank, so nitrates are assumed to be safer, and they may be, somewhat. But adding any form of nitrogen beyond a trace amount is likely putting the fish at risk. Minimizing stress is always safer.
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Old 04-30-2012, 01:06 PM   #14
 
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Hmm... lots of interesting stuff here, thanks for the replies!

Sorting through the misinformation/personal opinions and trying to find truth is 90% of all my questions! It's difficult for a beginner to try to figure out, so I appreciate you guys taking the time to go over this stuff with me over and over again! I'm a bit thick-skulled at times, but I'd really rather have the basics of understanding before I come across any true problems - and hopefully prevent a few!

Byron, I've read through your article on bacteria several times over now - and I DO learn more every time I look through it. Might be time for a re-read. I'm so glad that you have these out and available to me - they've proven invaluable time and time again.

I DO have soft water from tap, and have decided to stock in the future for my water conditions, rather than trying to adjust hardness. It's just easier for me, as a beginner, to do it this way. Ph is nice - 7.6, Kh is 2dgh (35.8 ppm) and Gh is 6dgh (107.4 ppm). I'm keeping a close eye on things here, especially with the Kh being so low. So from what you say, Byron, I can assume that calcium and magnesium are very probably lacking in my tank? What, if anything, do you recommend I do so supplement this? Calcium is something I've already been looking into, due to the snails, who really shouldn't be kept in my water to begin with. Still, at present time all plant-life EXCEPT for the hornwort is thriving and growing in quickly. That said - should I leave well enough alone and not fix something that doesn't appear to be broken? Or is it likely that I'll run into problems and have trouble back-pedaling to fix them if I don't act proactively?

The information you give regarding to vacuum or not makes sense, and does warrant further investigation. But. . . really. . . leaving wastes to rot in the tank, which IS a closed system as you've pointed out, will lead to the release of ammonia. I understand that the 'toxins' produced in this fashion, and co2 may be beneficial for the plantlife, and even the bacteria, but. . . the fish? I know you put fish above all else - but this is still confusing me, as it seems quite backward to everything else I've read. Are there any sources - books, articles, etc - you can recommend to me that might explain this more in-depth from a whole-aquarium viewpoint? I understand that CO2 in a low-tech tank is one of those things that puts a 'cap' on things. Something that you want to have enough of, but is a bit difficult to get without switching to high-tech, or supplementing in other ways. In this sense. . . what you say does make sense, but it still seems. . . dangerous to the finned ones! The information you give regarding the growth rate of the plants with and without fish interests me. . . and you know that I have many of the same plants as you do - all of mine are low light beginner plants, so this would likely apply to me, as well. Might have to do my own experimentation here!

I'm SO glad to find you in agreement with keeping nitrates as low as possible! That one made me nervous (didn't come from you, lol)

Redchigh, It's confusing, I have 3 planted tanks. My MAIN tank is the most planted, it's a 29 gallon tall and has had 0's across the board (nh4,no2,1o3,po43) for well over a month now. The 5g frog tank is all 0's, but nitrates are at 5 - steady and holding. The 10g tank is barely planted - this is where the problematic Hornwort lives (along with the accidental Spirallis Crypts now), again all 0's, but nitrate sits at 7.5. I might be wrong here, but from what I've read, it's actually not very common to find much nitrates in natural bodies of water. I might have to re-check this information with a few books I have. . . You ARE right in that Hornwort IS a nitrogen hog - which is why I got it to help with the accidental cycle situation I found myself in. . . and I see where you're coming from, but again the idea of over-feeding to encourage toxins just. . . doesn't sit right with me! Also considering that this is a QT/hospital tank, and stocking will change about from time to time. . . it's more important for the fish's health to maintain low levels of feeding and a very stable system. If I go mucking about with it, then it will be more difficult for me to track what's happening in there with the bacteria as I change out the fish. And that doesn't even get into the health of the fish themselves. Thanks for the idea, though. I won't do it, but I suspect you may be right where the hornwort is concerned. I think this is EXACTLY why it's failing - it's a nutrient issue.

I agree with Byron's last post 100% here. . . I'm really proud of my 29g tank with o nitrates, and I hope to keep it that way, though I know that this isn't likely to happen as it gets fully stocked. . . I'll still do my best. Which brings me back to the original bit about not vacuuming the substrate. . . which will cause ammonia - through the chain and ending up with a higher nitrate level! Or... is the theory that the plants will take care of the ammonia/ammonium BEFORE it gets through the entire cycle OR affects the fish. . . so, if this mulm is kept at the ideal balance. . . everything should be stable, but the plants 'fatter' for the extra food?
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Old 04-30-2012, 02:31 PM   #15
 
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Well, the 'overfeeding' technique is used often with soil. I'm not encouraging food to rot in the bottom, only to make the fish produce more 'fertiliser'. You're right though, in a lightly planted tank I wouldn't do it.

If you're interested in the biology of planted aquaria, try Diana Walstad's Ecology of the Planted Aquarium. It's quite detailed. My only disagreement, is that she describes soil substrates as the only way, instead of one of many.

She definately goes into good detail on how bacteria in the substrate break down wastes and produce CO2 and nitrogen gas.
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Old 04-30-2012, 02:38 PM   #16
 
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AWESOME! Thanks. . . I'm always looking for good books to devour! I'll definitely check into that one! You rock!!!
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Old 04-30-2012, 04:45 PM   #17
 
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Quote:
I DO have soft water from tap, and have decided to stock in the future for my water conditions, rather than trying to adjust hardness. It's just easier for me, as a beginner, to do it this way. Ph is nice - 7.6, Kh is 2dgh (35.8 ppm) and Gh is 6dgh (107.4 ppm). I'm keeping a close eye on things here, especially with the Kh being so low. So from what you say, Byron, I can assume that calcium and magnesium are very probably lacking in my tank? What, if anything, do you recommend I do so supplement this? Calcium is something I've already been looking into, due to the snails, who really shouldn't be kept in my water to begin with. Still, at present time all plant-life EXCEPT for the Hornwort is thriving and growing in quickly. That said - should I leave well enough alone and not fix something that doesn't appear to be broken? Or is it likely that I'll run into problems and have trouble back-pedaling to fix them if I don't act proactively?
From the plant perspective, a GH of 6 is fine. Walstad mentioned a GH of 4 being minimum with respect to the "hard water" minerals. After 2-3 months of using Equilibrium to raise my GH from zero out of the tap to 5-6 dGH in the various tanks, the plants have responded, except for a few which I have now narrowed down to potassium.

If you intend to keep soft water fish, your tap water is ideal. And you are wise to select fish that suit your water, it makes life much easier. All these additives are expensive, and over several months I have experimented with just about every method suitable for a planted tank.

Your pH should lower below 7 as the tank settles biologically. It needs to, in order to better match the fish (and plants for that matter) with the GH. So I would go with soft water fish and monitor things.

Quote:
The information you give regarding to vacuum or not makes sense, and does warrant further investigation. But. . . really. . . leaving wastes to rot in the tank, which IS a closed system as you've pointed out, will lead to the release of ammonia. I understand that the 'toxins' produced in this fashion, and co2 may be beneficial for the plantlife, and even the bacteria, but. . . the fish? I know you put fish above all else - but this is still confusing me, as it seems quite backward to everything else I've read. Are there any sources - books, articles, etc - you can recommend to me that might explain this more in-depth from a whole-aquarium viewpoint? I understand that CO2 in a low-tech tank is one of those things that puts a 'cap' on things. Something that you want to have enough of, but is a bit difficult to get without switching to high-tech, or supplementing in other ways. In this sense. . . what you say does make sense, but it still seems. . . dangerous to the finned ones! The information you give regarding the growth rate of the plants with and without fish interests me. . . and you know that I have many of the same plants as you do - all of mine are low light beginner plants, so this would likely apply to me, as well. Might have to do my own experimentation here!
The Walstad book redchigh mentioned contains about the best explanation of this. I have used this and some other works for my understanding.

The key is balance. Lots of plants, not overstocking fish [unlike Walstad, I have more than a moderate fish load, but that is why I stay away from soil, I have fish tanks that happen to have plants in them, not planted tanks with some fish], not overfeeding, and doing weekly 50% or more water changes. The ammonia released by the breakdown of organics will not overwhelm a balanced system. As Tom Barr told me, we would be amazed at how much ammonia a tank of plants can take up, either as nutrient nitrogen or as toxic ammonia. Now, I wouldn't overload this with soil, another reason i do not recommend it. I never have ammonia in my tanks, in more than 15 years.

Hornwort: this plant prefers medium-hard to very hard water, it even is found in the rift lakes. It is also found in soft water like the Amazon River. But Kasselmann says it does better in harder water. This is a case where you may need to get rid of it and go with what works. Just as not all fish can be in the same aquarium, so too with plants. Go with what works together in your water, and you will have a healthier tank because everything will do well. [Could also be some allelopathy with one of the other plants, just a thought.]

Nitrates. As I said before, you should never see nitrates above 10ppm in a natural planted tank, and very often well below this. Mine run 0-5 ppm with the API test.

Byron.
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Old 05-01-2012, 09:10 AM   #18
 
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To be honest, I've been captivated by the idea of the Walstad tank from the moment I read of it - someday, I intend to try to build one. . . lol, but that time is not now! I have too much to learn, and am enjoying the fishy side of things too much!

Thanks for the note - I have been keeping a close eye on the Ph, most especially since the addition of driftwood and plants, and will continue to do so. I really want to avoid being forced into doing anything to try to change the hardness of the tank. It gets too complicated to keep steady - at least for a beginner. I DO still have my Mollies, but thus far they're well. I got them before I knew any better, but won't be getting any other creatures that won't find my water ideal.

You might be right that it's just time for the Hornwort to be done. . . But it got my tanks through cycling, so I feel somehow indebted to it, and can't just toss it out, lol! I'll try to up the ferts, and if it doesn't make it, at least I know I tried. I hadn't read that it does best in hard water - that might just be the problem

Thus far, my Nitrates are well under 10, and as expected from what you've said, the more densely planted tank(s) have the lowest levels. I accidentally found that balance in my main tank, and hopefully have gained the understanding to keep it that way - and improve the others

Now I know I'm beating this thread to death. . . so I'm just going to ask ONE more question, and then leave it alone. . .

You continuously say water changes of 50% or MORE. . . thus far, I've been advised to keep the water changes to around 10% - maybe as high as 30%. But 50% only in an emergency/cycling situation, presumably because of the stress the process causes to the fish. So why do you recommend such a high volume to be changed out so often? Does this have to do with the fact that you don't vacuum the substrate surface? I understand that it's a closed system, but if the bacterial colonies are in balance as they should be, and toxins are not present in the water. . . why so much?
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Old 05-01-2012, 11:31 AM   #19
 
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Thanks for the note - I have been keeping a close eye on the Ph, most especially since the addition of driftwood and plants, and will continue to do so. I really want to avoid being forced into doing anything to try to change the hardness of the tank. It gets too complicated to keep steady - at least for a beginner. I DO still have my Mollies, but thus far they're well. I got them before I knew any better, but won't be getting any other creatures that won't find my water ideal.
If you want to save them, set up a tank just for them (size according to how many) using crushed coral/aragonite fine gravel or sand as the substrate. This will provide the mineral they need...and i can assure you they need it. Molly will not live well in soft water. They will be highly stressed, their physiology will be terribly affected, and they will slowly die over a period of weeks, perhaps months. They usually succumb to shimmy and fungus infections before actually dying, all caused by the soft water. We cannot change nature.

Quote:
You continuously say water changes of 50% or MORE. . . thus far, I've been advised to keep the water changes to around 10% - maybe as high as 30%. But 50% only in an emergency/cycling situation, presumably because of the stress the process causes to the fish. So why do you recommend such a high volume to be changed out so often? Does this have to do with the fact that you don't vacuum the substrate surface? I understand that it's a closed system, but if the bacterial colonies are in balance as they should be, and toxins are not present in the water. . . why so much?
I must get that article on water changes going.

Water changes are the most important aspect of tank maintenance. You can let the fish go without feeding for a couple of weeks and it will not harm them. But you cannot fore-go water changes.

At this point I will mention that this is contrary to Walstad and Barr. But they do not maintain fish tanks in the sense that most of us do; they maintain planted tanks that might have fish in them, or they have "moderate" fish stocking. But even so, they are missing something.

"Stuff" that I have often termed "crud" accumulates in any tank with fish, and the only way to remove it is with a water change. Plants can handle some of this, in time, and if not overwhelmed. But at the level of stocking most of us have, a weekly water change of half the tank is necessary. This crud is urine (about 30% of the fish's body mass is excreted as urine every day), pheromones, dissolved waste, bio-filtration end products and other pollution. TDS (total dissolved solids) build up quickly; these come from the water conditioner we have to use, from fish foods, from any medications, and from just about any substance entering the water. GH is one aspect of TDS, but only one. Increasing TDS with soft water fish is critical. There is not much point in fussing over soft water if one is going to ignore all the other TDS.

The other aspect is water stability. The larger and more frequent the water changes, the more stable will be the water. Now, this assumes we are relatively close in GH and pH and temperature. These are relatively easy to control--another reason for selecting fish that match your water parameters. They will be healthier than fish that do not match, either because of stress from inappropriate parameters or from stress caused by using chemicals with TDS to adjust the chemistry. Any biologist/ichthyologist will tell you this. The more water you change, the more stable the chemistry will be, and this is crucial for fish.

Jack Wattley is an acknowledged authority on discus, having bred and raised them for most of his nearly 80 years. In almost every one of his monthly TFH columns he mentions the necessity of water changes, pointing out that in his tanks he performs 90% water changes every day. There are hatcheries in SE Asia that perform 3 and 4 such changes every day. With respect to the water stability and health of the fish, you simply cannot overdo water changes. As for those who say water changes stress fish, the more you do the more accustomed they will be to the commotion, and even come to enjoy it. I've had fish nibbling the hairs on my arm when I've been in the tank trimming plants. And a siphon sticking in one end pulling out water or adding fresh water is not going to stress fish.

Byron.
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Old 05-01-2012, 03:48 PM   #20
 
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Originally Posted by Byron View Post
I must get that article on water changes going.
I agree! You must get tired of repeating yourself for every new aquarist that saunters through, and I've learned a lot from the other articles you've posted up!

Thank you for taking the time to clarify the points you've made! As I promised, I'll let this thread die now I have MORE than enough information to solve my original problem, and to understand the why if I can't - plus a whole lot of new stuff to look into!

Thanks again!
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