QUOTE from a plant forum:
I've had planted tanks for years now. My 75 gallon is fitted with Kissell lighting, pressurized CO2 and dosing with dry fertilizers.
For years plants kept growing like crazy and I was sick of trimming them. Then, suddenly they stopped growing completely and started getting covered with diatom algae. Most fast-growing plants died off and I was left with just the moderate/slow growing plants. There was no change in terms of the tank's maintenance/conditions...
Now I've started again with new plants, CO2 and dosing, but my plants are not pearling again!!! I used to read forums where people complained about their plants not growing and used to wonder how that was even possible - coz plants need light, CO2 and fertilization. But strange that despite my providing all three, it's NOT working!!!
I've even tried switching from dry ferts to Flourish line of products, but that didn't work. Could my Kessil Tuna Sun lighting be an issue? (I used them when my plants were growing like crazy and the lighting is still pretty new and bright).
ANY suggestions/recommendations would be MUCH appreciated!!! I'd love for my plants to start growing/pearling like they used to!!!
Thanks in advance!”
What is being asked above is just one example of what happens when plants need a resting period and/or your substrate is exhausted of all nutrients to accommodate your plant’s needs. Nonetheless, if you read the top question carefully you may find there is a lot of information missing like parameters of CO2, pH, Nitrates, does substrate sit directly on bottom of tank, substrate oxygen levels, Redox, TDS, etc.., etc... The questions to this question could go on and on and most hobbyist will think it’s time to start anew with newer and better substrate; some costing hundreds of dollars.
However, don’t throw that old substrate away because it’s time to rejuvenate it with iron once again. In most cases it’s not the substrate but it’s how the tank was initially set up in the first place. Very fine substrates, example: sand and/or dirt, will cause the most problems in the long run because they will compact even more so than other mediums will or should I say they will show the first signs of trouble in the least amount of time given. This has already been scientifically proven, but some hobbyist refuses to heed to science disciplines an insist on using these mediums as a cheap alterative substrate in closed systems. Water movement through the substrate will change and so will its electrical properties as far as mV readings go. Hobbyist do not own the right testing equipment to test such changes in the substrate so these insults, chemical and biological changes go unabated far months or even years. If back in the late seventies using these substrates failed: Then why would they work any differently today using the same methods?
The link above will tell you of a very cheap product that will once again enhance your substrate to its original state. The product/s are called Ironite (this is a substitute for Laterite clay because it’s getting harder to find in the UK and USA) and CaribSea's Eco Complete substrate. In the USA Ironite is sold in most garden centers and hardware store across the country. It does require some rethinking on the hobbyist part on how and why your substrate became exhausted and did not replenish itself from the water column with new nutrients and ions.
As we all know farmers rotate their crops as not to exhaust the ground of all its nutrients and sometimes even plant nutrient giving plants in their fields like Medicago sativa (Alfalfa) so as not to exhaust any available nutrient supply that is left in the soil.
Well the same thing happens in our aquatic planted tanks but hobbyists think just because they add fertilizers to the substrate that, that will do the trick. Moreover, because the substrate has not been lifted off the bottom of the aquarium (like using a plenum) the chemical and biological pathway that were once open to chemical and biological mediators has now stopped or slowed down to the point that available ions are not moving in and out of the substrate as freely as when first set up. Now the substrate has become and algae friendly source of food and higher order plants hobbyist use are exposed to these inhibitors from anaerobic zones from the substrate that impede the plants ability to photosynthesize. Algae on the other hand is a lover of Nitrates, ammonia ions and phosphates and the soil/substrate then become too acidic, that they become the dominating factor in the ecosystem along with the unwanted cyanobacteria that plagues ponds and aquarium alike. Until the substrate becomes open to the chemical and biological mediators and once again to oxygen it will stay as a death pool or a plant inhibitor.
As we all know farmers an even golf courses as with their turf, will aerate the ground by either turning it over or by aerating tools that will punch holes or core the turf to keep it open to aid beneficial bacteria. Aerating or aeration is nothing new to gardeners and formers but it seems to be something that hobbyist have overlooked by placing a substrate directly on the bottom of their tanks and not allowing oxygen to penetrate unabated into their substrates. Time then become their enemy and it seems like time always wins the battel of oxygen depredation in the substrate. Hobbyist depend on the diffusion of ions will always be open to mediators but this has been proven it’s just not so.
When I experimented with different substrates with the Anoxic Filtration System, permeability and porewater capability with different substrates change with time because of unforeseen insults that change the electrical properties of the substrate. Over time the permeability and porewater management will change and in most cases, will change for the worse than the better.
The biggest biological filter of a planted tank is the substrate yet most hobbyist fail to realize their mistakes until the precipice of algae and cyanobacteria take over and dominate the higher order plants they are trying to grow. Affirmative action now must be taken and soon. It will not matter how much light, fertilizers or CO2 is added to the system because chemical and biological mediators are not working properly any longer.
To rectify this problem is easy and it does not require the hobbyist to buy new and/or better substrate. It is now time to do it right and forget about what you thought was the right way and this time do it right once and for all. The substrate has to be one that is lifted off the bottom of the tank glass bottom using a plenum and then add a ½” of substrate on top of the plenum. Then add Ironite, about 1/8” or less on top of that, then add the rest of the substrate to build the substrate up to 3-4” high for good root and root hair development. Make sure when you plant your plants that you do not disturbed this Ironite layer are it will turn your tank cloudy. It will look unsightly for a few days but it will eventually subside.
You have now have added iron back into the substrate to benefit not only the plants but also the bacteria that in their initial inceptive cell development need the iron ion to speed up growth. Now the diffusion of ions through the substrate will be unimpeded and oxygen and ions through electrical charge will stay open to biological and chemical mediators for years to come. I have had tanks set up for over 10-years without ever having a complete teardown of the system and Nitrates were at a low 5-ppm or less. Oxygen levels were at 1-ppm to .5-ppm in the substrate, low, but still good enough to keep heterotrophic facultative bacteria alive and working and leaving the ammonia ion for the plants to assimilate. I have Biocenosis clarification baskets set up in a similar theoretical way in an Anoxic filter stay open to chemical and biological mediators far over 28-years now without clogging and changing the porewater and permeability of the baskets themselves.
Plants look for the ammonia ion first before they will use the Nitrogen ion because it is a food source that requires less chemical work and energy for their amino acids and proteins. Nevertheless, hydrogen sulfide and methane are not part of the equation that plants as a foodsource need, but this is exactly what hobbyist are producing when they add a substrate directly to the bottom of an aquarium. If you could look underneath a fish tank with the substrate directly on the bottom you would see in just a few months the blackening of the substrate.
Here is a true example of just how important oxygen is to plant roots. Martha Stewart opens her house and gardens for people to visit from time to time. After showing her garden off to onlookers a few days later her lawn began to die off. Her gardener was perplexed over this very strange outcome and thought it was some kind of lawn disease that was killing off the grass. However, what they found out was prior to the showing of her garden it had rained and made the ground soft. By people walking on the lawn they compacted the earth to the point that oxygen depredation was taking place and the grass started dying off. It was not because of a diseased as they had thought, but because the roots of the grass no longer received oxygen and nutrients as they did preceding the showing.
The same thing happens in our aquariums. The substrate become more compact as time goes on just through gravity. If the substrate was on the low side of oxygen requirement by placing the substrate directly on the bottom of the aquarium in the first place then it will not take much more to cut off the oxygen altogether and cause oxygen depredation in the substrate. The exchange of ions will be hindering the chemolithotrophs/chemoautotrophic to fix their carbon needs.
Here is another interesting read on my blog about Nitrates in ponds but it also applies to aquariums, too. Think very hard about placing fertilizer tabs that are nothing but nitrates into your substrate. In fact, anything that can saturate the substrate full of Nitrates and phosphates be apprehensive about using.
QUOTE from Takayuki Ezaki MD; Ph.D. Prof. bacteriologist.
“Nitrate will affect your TDS readings - the other damaging effect of nitrates were explained 14 years ago, Takayuki Ezaki MD; Ph.D. Prof. bacteriologist, writing on behalf of the ZNA Research Division, shared his observations of the effect of nitrates on the white ground of Kohaku. He urged that the maximum concentration of nitrate be 15 ppm, stating: "Anything more than this and the skin gradually begins to deteriorate, improving again as the concentration lessens." He recommended that if nitrates can be kept at 5 ppm or less, "the skin becomes so white it virtually shines". He ascribed the negative effect of nitrates on (1) reduced the ability to discharge metabolic toxins from the body, resulting in buildup of metabolic wastes in the skin, and (2) on the pond water becoming less receptive to dissolution of atmospheric oxygen into the water. He expressed the view that nitrate levels above 10 ppm adversely affect oxygen dissolving into the water column such that saturation levels at given temperatures cannot be readily maintained.” Several scientists have studied mineral levels in different bodies of water, and have found that the levels of phosphates and nitrates heavily impact the overall health of the water and its inhabitants. (Yanamadala, 2005)
Remember that plants will only start pearling during photosynthesis only when oxygen levels in the tank are at saturation point for a given temperature. The colder the water is, the easier it is for plants to start pearling at a given temperature and the easier it is for the water to reach oxygen saturation point. The warmer the water, the harder it is for oxygen to reach saturation point of that given temperature. As an aquarium substrate begins to age and chemical and biological pathway becoming impeded oxygen saturation levels cannot be reached as easily as when the aquarium was newly setup as explained above.
I’m trying not to get into a lot of science here like I do in my blog:
But sometimes understanding what we scientist know will really help the hobbyist in understand why some things go array and for what reasons they do.
Some more interesting reading that hobbyist may like to read about fertilizer tabs that so many use in ponds and fish tanks and the reduction of ions in the substrate.
 QUOTE: “With CaribSea's Eco Complete substrate, you can add vibrancy to your freshwater or saltwater aquarium as well as bring out the color of your plants, fish and other aquatic life. Containing essential nutrients, including iron, calcium, magnesium and sulfur in addition to over 25 other mineral supplements, CaribSea Eco Complete Planted Black Aquarium Substrate is the healthy choice for your aquarium plants and other aquatic life. CaribSea's all-natural formula makes the perfect substrate to not only enhance the look of your aquarium, but to also maintain the health of your live plants and keep them well nourished. Unlike most synthetic aquarium rocks, CaribSea Eco Complete contains a live Heterotrophic Bacteria, which is beneficial for sustaining a healthy aquatic environment as it helps to convert organic waste into a natural plant food. This Eco Complete fish tank rock gravel comes in a range of large and small grain gravel sizes that makes for a porous foundation for plants, which stimulates for healthy root growth and optimal bacterial efficiency. This substrate helps to maintain a healthy aquatic environment as it will not increase pH or water hardness as it is free of any carbonates and nitrates. This beautiful dark substrate creates a stunning contrast, which not only brings out the brilliant colors of your fish and live plants, but also helps to reduce fish stress. Add CaribSea Eco Complete substrate to your aquarium today and watch your plants flourish and your fish thrive.”
NOTE: Cyanobacteria is about 4-5 billion years old and becomes the dominating bacteria once other bacteria become depleted or reduce.