You are at The Krib ->Plants ->Plant People ->George Booth [E-mail]
From: booth-at-hplvec.LVLD.HP.COM (George Booth)
Date: Tue, 16 Feb 1993 20:09:27 GMT
[...] Let me expound on my experiences to date.

For people who joined *.aquaria recently, my wife (Karla) and I have 4 heavily planted tanks based on the priciples outlined in Dupla's "The Optimum Aquarium". Like most folks, we started out with a typical setup and have "progressed" towards higher tech equipment. Karla has a PhD in Biochemistry and I am an Electrical Engineer, so we attempt to maintain some semblance of scientific methodology in our aquatic efforts.

Until we read The Optimum Aquarium (TOA), we had pretty poor luck growing plants. We bought random fertilizers and additives but nothing really worked. We maintained a nice looking plant tank only by continuously buying new plants to replace those that died. We were frequent visitors to the local fish shop and became friends with the owners (no doubt because we looked like walking dollar signs to them).

Reading (and rereading many times) TOA led us to understand the principles that took us from the "luck" category of planted aquaria. I'll be the first to say that the book is hard to read and is a blatant sales pitch for the Dupla products. It takes some independent research and experience before you catch on to what Horst and Kipper are talking about. They (or the translator, Albert Theil) left out some key connections about the concepts behind TOA that put it in an understandable form.

Some people complain about the "10 Golden Rules for the Optimum Aquarium" presented in the book, especially since each of the 10 rules has some Dupla products associated with them. Some folks say "There are only three [or four or five] rules for fishkeeping". TOA rules are mostly common-sense things that everyone does anyway, with only two that go beyond standard practice - CO2 injection and substrate heating. Granted, Dupla has products, usually very expensive products, that optimize the application of the 10 rules, but most of the stuff can be purchased or DIY with some understanding of the basic principles.

So, enough background.

We have 4 plant tanks; 55 gallon, 85g, 90g and 100g. We have set up each tank with differing equipment so we can "compare and contrast" the effects of the equipment and technologies involved.

Low Tech 55 gallon Tank

The 55 gallon tank is the base level and is set up pretty much the way 80% of U.S. aquariums are set up. It's a standard 55 gallon glass tank with an undergravel filter (UGF) run by two Hagen 201 powerheads. The UGF is supplemented by an Eheim 2213 canister filter with various "efie-things" inside. An Eheim "Surface Extractor" is the input to the canister and removes the oily protein scum that tends to form on the surface of freshweter (and saltwater ?) tanks. An Ebo-Jaeger 150w heater keeps the water at 78 F. A Sears shop light with a 40w Triton and 40w Penn-Plax Ultra Tri-Lux provide light. The light is on 11 hours per day. Around 2.5" of 1/16-1/8" quartz gravel is used. Some laterite balls are placed around the base of some of the plants. No CO2 injection is used.

50% of the water is changed every 10 days (or two weeks, depending on our mood :-). Duplagan water conditioner is used at water changes along with DuplaPlant tablets. One DuplaPlant-24 drop is added daily, starting 3 days after a water change. We add some magnesium sulfate to the water to boost GH but do not change the KH (our tap water is very soft). The pH of the tank stays around 7.0, KH=1 degree, GH=3.5 degrees.

The tank has 4 adult Rainbowfish (4-6"), 1 large angelfish, 1 clown loach, 1 unidentified "pleco" and 3 corydoras. There is 1 large E. bleheri, a few stems of Hygrophila polysperma, some ambulia, and 3 or 4 varieties of crypts. Nothing does very well except for the crypts. They seem to like this tank better than most of the others.

We had an outbreak of blue-green slime algae last summer that was cured with Maracyn. We get a greasy, dark grey algae growing in little smears on the front glass (removed during water changes). The plants don't grow very fast, making this tank relatively maintenance free. We vacuum the gravel as much as possible since the UGF collects a lot of crud.

This tank is pretty boring. We often think about taking it down and selling it to avoid the extra half hour on water changing day.

85 Gallon Rainbow Tank

We bought the 85g tank 5 years ago and was our first aquarium since we moved to Colorado in 1977. We had tanks during college ('70-'74) and while living in LA ('74-'77), but never tried to grow plants beyond an occaisional "Wonder Bulb" (aponogeton). We struggled with the 85 until we discovered TOA. The difference was CO2 injection.

The 85 gallon acrylic tank is the next level of technology by virtue of a manual CO2 inection system. Like the 55g, it has an UGF with powerheads and an Ehiem 2217 canister with a Surface Extractor. Two Ebo-Jaeger 100w heater keeps the water at 76 F. A pair of Sears shop lights in a custom hood holding 2 40w Triton and 2 40w Penn-Plax Ultra Tri-Lux provide light. The light is on 11 hours per day. Around 2.5" of 1/16-1/8" quartz gravel is used. Some laterite balls are placed around the base of some of the plants.

The CO2 system started as a Dupla "Starter Kit" but has been upgraded with a 5 pound bottle and a commercial regulator. The CO2 goes through a Dupla bubble counter then into the inlet strainer of the canister filter. In general, I would not recommend the Dupla starter kit (or any other Dupla CO2 setup). The Dupla bubble counter is very useful, but the other parts of the system are much cheaper if you DIY.

30% of the water is changed every 10 days or so. Duplagan water conditioner is used at water changes along with DuplaPlant tablets. Two DuplaPlant-24 drops are added daily, starting 3 days after a water change. We add sodium bicarbonate and calcium carbonate to set the GH and KH at desired levles. The pH of the tank stays around 6.8, KH=4 degrees, GH=3.5 degrees, CO2=15 ppm.

The tank has 10 adult Rainbowfish (4-6"), 1 unidentified "pleco", 4 corydoras, 1 farlowella and 6 ottocinclus. There is 1 large E. hormani, large clumps of rotala macranda, bacopa caroliniana, ludwigia sp., a dozen or so samolus parviflorus and amoreacea aquatica, a large Jave fern, a clump of Java moss, various anubias, a clump of hydrocotyle leucephalia (sp?), 6 stems of nomaphila stricta and a few crypts. All the plants except the crypts are thriving.

About the only substantial difference between this tank and the 55g is the CO2 injection. The difference in plant growth is amazing. The difference in appearance is amazing. We trim plants at every water change and put cuttings in the 55g and sell the rest to the local store.

The drawbacks to this tank are the UGF and the manual CO2 system. The tank will exhibit long term cycles of looking great and going downhill. The downhill periods are usually turned around with a thorough gravel vacuuming. We also see a long term drift in pH due to the manual CO2 system. It runs continuously and it is hard to get just the right bubble rate to offset CO2 outgassing. We don't see more than 0.2 pH units difference between daytime when the plants are using CO2 and producing O2 and nightime when they are using O2 and producing CO2. There is a 10 ppm difference in CO2, but the 4 degrees of KH keeps the pH fairly stable.

This tank clearly refutes the myth that under gravel filtration per se is bad for plants. The plants thrive in this tank. IMHO, what is bad for plants is excess decomposing crud building up in the gravel.

Unfortunately, UGF tend to pull crud into the gravel and people tend to not clean the gravel as much as they should, creating poor conditions for plants. WHEN PROPERLY CONFIGURED AND MAINTAINED, an UGF will work about the same as substrate heating coils. I don't believe that RUGFs will perform as well. Again, IMHO, RUGF *seems* to work better because it is difficult to properly set up an UGF for plants. Ditto for "rich" substrates of potting soil, laterite, Hilena-D and other mung. An understanding of how the substrate works with plants and nutrients leads to this conclusion (see the last section for more details).

100 gallon Discus Tank

The 100 gallon Discus tank was set up over 2 1/2 years ago when we decided to get closer to an Optimum Aquarium. It follows all the principles of TOA except for undergravel heating coils (because of the expense). This tank is called the Almost Optimum Aquarium (AOA).

The 100 gallon tank is the next step in technology because it uses a trickle filter instead of an UGF. Like the 85g, it has an Ehiem 2217 canister filter for additonal mechanical filtering and water circulation. Two Ebo-Jaeger 150w heater keep the water at 82 F. Rena end caps, Triton Enhancers and magnetic ballasts in a custom hood hold 2 40w Triton and 2 40w Penn-Plax Ultra Tri-Lux provide light. The light is on 11 hours per day. Around 3.5" of 1/16-1/8" quartz gravel is used with powdered laterite in the lower inch.

The automated CO2 system uses a 10 pound bottle, commercial regulator, solenoid and valves, a Dupla bubble counter and CO2 reactor and a Sandpoint II ORP and pH controller (ORP is not controlled).

30% of the water is changed every 10 days or so. Duplagan water conditioner is used at water changes along with DuplaPlant tablets. Two DuplaPlant-24 drops are added daily, starting 3 days after a water change. We add sodium bicarbonate and calcium carbonate to set the GH and KH at desired levels. The pH of the tank stays around 6.8, KH=4 degrees, GH=2 degrees, CO2=15 ppm.

The tank has 5 adult discus (one pair spawns every 10 days), 24 cardinal tetras, 1 unidentified "pleco", 6 corydoras, 1 farlowella, 2 Siamese algae eaters and 2 ottocinclus. There is 1 huge E. bleheri, large clumps of rotala macranda and indica, ludwigia sp., 1 large E. maior, clusters of E. quadricostatus, a clump of Java moss, various anubias, 6 stems of nomaphila stricta and a few crypts. All the plants except the crypts are thriving.

About the only substantial difference between this tank and the 85g is the lack of forced water circulation in the gravel and the temperature. Different plants are used becuase of the temperature difference, but growth is the same. We find the gravel stays much cleaner than in the 85g since detritus is not pulled into the gravel.

We were unsure about not providing a water circulation mechanism in the substrate but reasoned that plant roots would provide oxygen and Malaysian snails would keep it from compacting.

What we found was that the plants flourished for about a year. At that time we noticed a general decline in the overall appearance of the plants. Nothing dramatic, perhaps a little more red algae on the anubias and a tendency for hair and thread algae to grow a little faster. A slight slowdown in growth was noticed. After 18 months, we removed all the plants and did a complete gravel vacuuming and added some laterite balls. This restored the tank to it's previous conditions and we again saw great plant growth.

90 gallon Discus Tank

The 90 gallon Discus tank was set up about 1 1/2 years ago when we decided to go all out. It completely follows all the principles of TOA. This tank is called the Super Show Tank (SST) and was described in the Aug, Sept, Oct and Dec (1992) issues of Aquarium Fish Magazine (AFM). The SST is the next (last ?) step in technology because it uses substrate heating coils and metal halide lighting.

The tank is all glass and has an open top so plants can grow emeresed. A trickle filter is used for all filtering and uses Dupla Yuppie-media BioKascade balls for media. It does not use a canister filter. An Ebo-Jaeger 200w heater augments the 250w heating coils to keep the water at 82 F. A Hamilton hood with 2 175w 5500K MH bulbs and two 40w Agrolite bulbs is on 11 hours per day. Around 3.5" of 1/16-1/8" quartz gravel is used with powdered laterite in the lower inch.

The automated CO2 system uses a 20 pound bottle, commercial regulator, solenoid and valves, a Dupla bubble counter and CO2 reactor and a Sandpoint II ORP and pH controller (ORP is not controlled).

30% of the water is changed every 10 days or so. Duplagan water conditioner is used at water changes along with DuplaPlant tablets. Two DuplaPlant-24 drops are added daily, starting 3 days after a water change. We add sodium bicarbonate and calcium carbonate to set the GH and KH at desired levels. The pH of the tank stays around 6.8, KH=4 degrees, GH=2 degrees, CO2=15 ppm.

The tank has 4 adult discus (one pair spawns every month), 10 lemon tetras, 1 Pekoltia "pleco", 7 corydoras (a baby showed up recently), 1 Siamese Algae eater and 2 ottocinclus. There is 1 huge E. osiris growing emersed, large clumps of rotala macranda and indica, ludwigia sp. and cardamine, 1 Barclaya longifolia, clusters of E. quadricostatus, 6 stems of Ammania gracilis, various anubias, 6 stems of nomaphila stricta (emersed and submersed), a clump of Heteranthera zosterifolia and a four varieties of crypts. *All* the plants are thriving.

The only differences between this tank and the 100g are the substrate heating coils, MH lights and lack of canister filter. The light levels as measured at the surface are about the same (12-15,000 Lux), so except for a spectral difference, the lighting is equivalent. The canister filter in the 100g provides extra mechanical filtration and, since it isn't cleaned as often as it should, probably acts as a nitrate source. As far as I'm concerned, the only substantial difference is the substrate heating coils.

The biological differences between this tank and the AOA and the 85g tank are very striking. The main thing that is noticable is the almost total lack of algae. While the other two tanks always seem on the verge of an algae outbreak, the SST seems to surpress aglae. We do find an occaisional strand of thread algae and the anubias get a little red algae, but other than that, it's algae free. Even the glass stays much cleaner.

All three tanks have the same additives (water conditioners and fertilizers) and are on the same maintenance cycles. All three are treated the same. The SST just seems to "work" a whole lot better.

Note that the SST has been running for about 18 months and has not shown any signs of a decline like the AOA and Rainbow tank. Why? Let me give my hypothesis.

Substrate conditions

After seeing how our tanks work, I've become convinced that substrate heating is the hot setup for plant tanks (no pun intended). A guy who was posting a couple of years ago (Jeff Frank) spelled it out, but it took this long for it to settle in.

Aquatic plants take in nutrients from both leaves and roots. Different plants get different proportions from leaves or roots, making it necessary to provide nutrient sources in the water and the substrate. As plants grow, they will deplete the nutrient sources and the depleted items must be replenished.

Nutrients in the water are easy to replace. Fish waste will provide nitrogen and phosporus compunds (usually too much :-). CO2 injection will provide carbon. Iron sources (Wimex, Dupla, Greenol, etc) will provide iron. Trace element formulations (Wimex, Dupla) or water changes (if you are lucky) will provide trace elements.

Note that iron needs to be in the proper ionic state (Fe++) to be used by plants, so it should be chelated with EDTA or some such. Unchelated iron will quickly oxidize to the Fe+++ state, making it unusable by plants. Other trace elements also exhibit this behavior. This is why Dupla has "daily drops" - they contain elements that are relatively unstable (or toxic in large doses) and need to be added in small doses at frequent intervals.

Nutrients in the substrate are a little tougher. A very common thing among aquarists is to provide a "rich" substrate. All kinds of goop is put in the bottom of the aquarium to provide the required nutrients. Peat, potting soil, laterite, Hilena D (whatever that is) and sheep manure are some of the more common items. These items may (or may not) provide the required nutrients, but the question of long term viability is unanswered. As the plants use the nutrients, what mechanism is replacing them? There is also a question about the "rich" substrate leaching who-knows-what into the water.

Perhaps long term viability is not a concern to some aquarists. These folks change aquatic interests (and their tank setups) about as often as they change underwear. If the rich substrate produces good results for 3 or 6 months, that's great. Or perhaps the plants they are using are "easy" plants and don't even need a rich substrate. As far as they are concerned, the peat and potting soil mixture "worked" and that's all they need to know.

Some folks aren't as concerned about water quality as others and as long as the 6 assorted tetras in their plant tank survive, they could care less about what the sheep manure is doing to their water.

People think that laterite is used in the substrate to provide iron. This is true to some extent since it does contain some iron. But the iron it contains will be used up fairly quickly. What laterite (and peat) really is providing is a chelating action. It has many negatively charged sites that attract positive ions (like Fe++ and NH4++) and hold the ions in the proper oxidized state until plant roots can use them. When the nutrients are linked to an organic compound, they are easily assimilated by the plant roots.

The substrate heating coils play a role in this by transporting the nutrients in the water to the laterite binding sites via the gentle convection currents created by the heat. The slow currents are good because they give the chemical binding a chance to occur. I would guess that rapid water flow would have a negative impact on this process. The heat in the substrate also speeds up the biological processes involved in the adsoprtion of nutrients. I also think that the aerobic bacteria in the gravel will tend to deplete oxygen, preventing or reducing the amount of oxidizing taking place.

Some speculation:

I think a properly tuned UGF would be able to perform this same function, but to a lesser extent. Laterite plugs, as well as decomposing crud, offers negative binding sites. A slow flow of aquarium water will move nutrients to the binding sites. Negative aspects of the UGF are too much oxygen, causing nutrients to be oxidized before becoming chelated, and the build up of excessive amounts of crud.

I think that RUGF would not work as well, since the water is biologically filtered before getting to the binding sites giving NH4++ a chance to be converted to NO2 and NO3. Also iron and other trace elements have a greater chance of being oxidized before arriving at a chelating site.

Summary

By having a range of technologies in our aquaria, I have satisfied myself that substrate heating and laterite are the best alternatives for providing nutrients to plants. As time and money permit, we will change our other tanks over to substrate heating.

The substrate heating coils and laterite provide an optimum *and* renewable source of nutrients for plant roots. In addition, they don't pull crud into the gravel like an UGF. There are other approaches to this, but the coils/laterite combination are easy to setup and operate.

I haven't worked out the costs yet, but I think you can get substrate heating for a lot less than the cost of a pure Dupla setup. I would recommend the Dupla heating coils, since they are not that costly by themselves and are very high quality. If a heating coil should go bad, you have to tear down the entire aquarium to fix it. Not a very appealing thought.

The 24v step-sown transformer can be had for a lot less than the DuplaMat transformer. This will be a big cost saving.

I have seen various temperature controllers offering in the magazines, all for a *lot* less than the Dupla or Tunze controllers. Extreme accuracy and rapid response aren't very important since the substrate coils are very slow acting (slow to warm up, slow to cool down).

The last component of the Dupla setup is the cable anchors. They offer suction cups with little plastic cable holders for $2 each and you need 60 or so of them. I would think there must be some kind of DIY approach that would work just a well, if not better.

------------------------------------------------------------------------
George L. Booth                           /\           I am
booth-at-hplvec.lvld.hp.com                 /vv\          here
Software Development Engineer       /\  /    \  /\      |
Manufacturing Test Division      /\/  \/      \/  \     v
Hewlett-Packard Company      ___/      \       \___\___________
Loveland, Colorado        
------------------------------------------------------------------------
[Continue to the next update or up to contents.]
Up to George Booth <- Plant People <- Plants <- The Krib
This page was last updated 21 February 1999