A lot of people talk about finding the balance in your tank but never talk about practical ways to achieve it. In this section, I want to talk about a couple of different setups and how balance is achieved. To achieve balance, I tend to look at the tank as a system, and the system needs to be designed as a whole to achieve balance. The biggest elements in this hobby are the balance of light, nutrients and plant selection.
SCENARIO 1: THE LOW ENERGY SETUP
Let’s say that someone in the hobby does not have a ton of money to spend. They want a lushly planted tank but cannot afford a high-energy setup and want low maintenance. So they go out and buy a tank kit from a local fish store with a low PAR (low energy) light and a Co2 system.
In this scenario, the equipment is going to dictate how we balance this tank. One can still achieve a nice little scape with a low energy setup, but they are going to need to choose plants that complement the low energy light and lower injection rate of Co2 injection. Let’s start with plant selection. Because we have a low energy light, we are going to need to choose slow-growing plants like Anubias, Java Fern, bucephalandra, Jungle Val. Faster growing plants like Rotala mancrandra, Hygroiphilia, or carpeting plants like staurogyne repens (s-repens) or Hemianthus callitrichoides (Baby Tears) will not do well in this tank because they are happier with higher light, lots of available nutrients in the water column including Co2 injection. The slower-growing plants will be happy with the lower light and because there is not an excess of light, it will help fend off algae. Over time these slow-growing plants might absorb all the nutrients in the tank so a basic fertilizer like NilocG’s Thrive would help make sure there were enough nutrients in the water column at all times. Since these plants are slow-growing, we don’t need to go crazy with these fertilizers and could possibly even get away with using less than directed. You will just need to watch your plants for signs (e.g. yellowing, small pinholes, twisting of leaves) that the leaves are needing more nutrients. As a side note, there are a lot of slow-growing plants that do not need a high nutrient substrate, so one could get away with an inert substrate like EcoComplete, Seachem Flourite and/or pool sand. For example, the Anubias and Java Fern can benefit from, but do not need an aquasoil to do well. Low light and a little nutrients in the water column and these plants are happy. Lastly, since we aren’t adding in large amounts of nutrients daily, we won’t have to process water changes as often. However, you will need to regularly monitor nitrates in your water and process water changes if/when they get too high. You should make sure your nitrates are never above 20ppm in a planted tank. You’ll need to ensure the water parameters of the water going in are similar to the water that is in your tank. Again, steady water parameters have a big impact on the stability of our tank.
So to recap, we have low light and low Co2, so only slow-growing, low demand plants. Because they are slow-growing we do not need a lot of fertilizers, but a little in the water column help and we do not necessarily need a nutrient-rich substrate if we choose plants that are not big root feeders. If one does choose to grow something like a cryptocoryne, an aquasoil would help. Ultimately, this is how we can achieve a balance in a low-energy setup.
SCENARIO 2: THE HIGH ENERGY SETUP
Let’s say that someone sees another tank that is super lush, densely packed and full of plant species including a massive carpet of baby tears. They have an unlimited budget and don’t care what it takes to get this lushest looking tank.
The balance of this tank is going to be designed around what the hobbyist wants to achieve and not around what equipment they can afford. Demanding plants, like carpeting hair grass or baby tears, need a high PAR light because the light needs to penetrate all the way down to the substrate and still be intense enough to give the hair grass or baby tears the intensity they need to thrive. Something like a Kessil 350, or a Twinstar 360E, or a fully loaded Coralife Aqua LED light would have more than enough intensity (PAR roughly around 120+) to power it's way down to the substrate. Now, with lights that have a high PAR output, the plants will require a lot of nutrients and Co2 as we are asking them to grow quickly. Generally speaking, the more intense the light is, the more nutrients the plants are going to go through. The less we limit, or the more we inject Co2 into the tank, the faster the plants grow. So we are definitely going to need to do with a pressurized Co2 system with something like an inline Co2 diffuser or a ceramic disc inside the tank connected to a timer that comes on around 1.5 hours before lights come on and 1.5 hours before the light turns off. Now, because we have high light and lots of CO2 for the plants to grow quickly, they are going to need lots of readily available nutrients at their disposal. I would address this by using an aquasoil like ADA’s Aquasoil, Fluval Stratum, or Dennerle Scaper Soil. I would also suggest liquid or dry dosing of fertilizers into the water column. This can be done easily by following the EI dosing regimens. This is where you mix your own fertilizers by following a recipe and dose little bits every day to ensure there is never a drop-off of available nutrients in the water column. With dosing large amounts of fertilizers we just need to make sure that we are processing frequent water changes to make sure that there is not a buildup on one type of nutrient. Generally speaking, water changes in a tank like this are processed once per week. When running the EI method, you change 50% of the water each week.
To recap, we have high light which stimulates fast growth. This fast growth is going to need to be supported by injecting Co2 and fertilizers into the water column to ensure the plants have all the nutrients they need at all time. Aquasoils are a great way to make sure rooted plants have lots of readily available nutrients. And because of all of the nutrients in the water column, we need to make sure we are processing weekly water changes to makes sure we don’t have a buildup of one fertilizer in particular.
FINAL THOUGHTS
No matter the scape, steady water quality is key. We need to be aware of our tanks GH, KH, PH, and nitrates as these can cause issues or instability in our water parameters. If your tap water is hard, get plants that like hard water and stick with that. If you want to keep softer water plants but your tap is too hard, you’ll need to remineralize RODI water to gain control of your water parameters. You can grow software plants in a hard water setup, but it’s not wise to grow hard water plants in a soft water environment. Overall, GH, KH and injecting Co2 are going to have a play on your PH. Don’t try and chase a specific PH, but learn what water parameters come easiest to you and what you have available at the moment, and base your tank around that. Furthermore, we need to make sure our Nitrates aren’t getting too high. This is more for the low-energy setups as the plants in the high-energy setup will soak up the available nitrogen. If your nitrates get over 20ppm, you'll need to process water changes to reduce the excess nitrates. Again, steady water parameters have a big impact on the stability of our tank.
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