WHAT IS IT AND WHY DO PLANTS NEED IT?
Since we are trying to house life (plants and animals) in our tanks, we need to make sure our water parameters are such that sustain life. You may have heard of incidents where water runoff into a lake caused high pH which killed off fish and other life forms. It is similar inside of our planted tanks; we are trying to find a balance of water parameters so that we don’t kill off the pretty, living things inside. The parameters that are of specific concern are oxygen levels, GH, KH, pH and Nitrogen (in several forms).
Oxygen – is required for animal life and “good” bacteria respiration. It is also required to oxidize compounds (as in turning ammonia→NO2→NO3).
pH – pH is the concentration measurement of hydrogen ions in a solution. But no sweat if you can’t remember what you learned back in chemistry 101, all you really need to know is there is an ideal range of pH that supports life. If you are getting your GH and KH levels where they need to be for the livestock and plants you are keeping, the PH will naturally follow. So there is no need to sweat about PH.
GH – GH or General Hardness is a measurement of dissolved solids in the water. Ideal water parameters are around 4º for GH (which is considered “soft water”).
KH – KH or Carbonate Hardness is the measurement of bicarbonate and carbonate ions in a solution. Again, Ideal water parameters are around 4º for KH.
Ammonia - This can come from other fish waste or rotting organic matter in the tank. Plants prefer ammonia over nitrates as a nutrient source , but ammonia can become toxic at around .25ppm, so this is why its important to cycle a tank WITHOUT fish in it before introducing them into the tank.
Nitrites - are slightly less toxic to fish than ammonia, but still toxic at around .5ppms.
Nitrates - This is the end of the nitrogen cycle and is also a macronutrient. We don't want zero nitrates, but we need to monitor nitrates to make sure they don't get out of control, and are in a specific ratio with phosphates.
Plants like all of these parameters to remain steady within a certain range. Large fluctuations in pH, GH and KH can create an unstable environment to which plants react negatively.
HOW IT WORKS IN A TANK
So let’s talk about water and keeping your water parameters stable for plants and livestock. The easiest way to go about it is... keep your GH and KH where they need to be for the livestock you are keeping and the PH will follow. Easy as that. This could mean that every time you process a water change you remineralize RODI water to the GH and KH where they need to be for your design and add that to your tank... and presto! You tank is happy an healthy.
The best way I find to add oxygen into our tanks is through surface skimming. This could be through a little surface skimmer you place in the tank, or through lily pipes that you attach to the inlet of your canister filter. Surface skimmers also remove a biofilm that forms on the surface of your water preventing gaseous exchanges like oxygen from getting into your tank, and your tank from off-gassing CO2. The most obvious reason why good oxygen levels are needed is for our livestock; like fish, frogs, shrimps, etc. A less obvious example would be organisms we cannot see, like beneficial bacteria that live in our substrates, biomedia, and on our glass.
Another way to introduce more oxygen into the water column is by having the outflow of a canister filter rippling along the water’s surface. This can be more than enough to keep optimal oxygen levels in our tank. This should be a small ripple and should not create white water or bubbles.
Lastly, if we an injecting CO2, while we are getting the right saturation figured out, we can have too much CO2 in the water column which can cause our fish to gasp for air. This can be rectified by letting our filters outlet splash a little on the surface of the water, or by adding an airstone into the water. Regardless of the tank size or setup, I would always recommend some sort of surface skimmer or a tank that has a built-in sump in the back that acts as a surface skimmer. Fluval sells an inexpensive surface skimmer that can be fitted to many canister filters to help with surface skimming, but I really like the clean look of a glass lily pipe.
pH, GH and KH
A common issue we battle in a high-tech tank is PH swings due to GH and KH water parameters. Ideal water parameters are around 4º for GH and KH. Some people are lucky enough to be in a sweet spot and be able to use their tap water. Some of us have to remove extra minerals in our tap water using RODI water and putting back what we need to get there. Furthermore, “buffing” substrates like ADA Amazonia pull down the KH of water over time. Understanding what we are putting in our tank is vital to having a thriving tank.
So how does one get to an ideal GH and KH? If your tap water’s is higher than in either parameter you will need to “cut” or dilute your tap water with distilled or RODI water because it essentially has 0º for GH and KH. Then, we “buffer” or add additives to get your GH or KH back to the ideal 4º for GH and KH. We use re-mineralizer, like Seachem Equilibrium, to increase GH, and Seachem’s Alkaline Buffer to increase KH. Seachem’s Alkaline Buffer is a sodium bicarbonate-based buffer, which is essentially baking soda, so I use that as my buffer in my tanks. So here is an example, if your tap water is at 8ºGH and 2ºKH, we need to cut the GH with RODI water, and then add buffers to get the KH back up. We would do 1 part Tap water, 1 part RODI, which dilutes the 8ºGH down to 4ºGH…. But lowers our 2ºKH down to 1ºKH, so we need to add sodium bicarbonate, baking soda to get it back up. GH and KH helps give us our PH. Your PH should hover around 6.5-6.8 during the day.
Here are some calculations to help you increase your KH with baking soda:
5 GAL + 10 Grams = 17dKH
10 GAL + 10 Grams = 8.5dKH
20 GAL + 10 Grams = 4.25dKH
50 GAL + 10 Grams = 1.7dKH
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, you’ll need to use or mix in RO/RODI water to help reduce the GH. If you use 100% RO/RODI water you need to make sure that you buff back up your GH and KH so that you don’t have PH swings. It is very important to keep the PH of your water consistent no matter what you are doing. PH swings are very hard on your plants and fish. You can grow soft water plants in a hard water setup, but it’s not wise to grow hard water plants in 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 the moment and base your tank around that.
Let’s talk about my experience in Long Beach, CA. My tap water was GH was testing at 15º (around 293ppm) and my KH was a 1 ºdkh (around 18ppm). This is highly unstable because the water was so hard (basic) that it was melting the fins of my fish down to their scales. Then I would introduce Co2 to the water which would increase my KH from 1 ºdkh throughout the day while it was on, and at night my Co2 would diffuse out of the water column due to surface agitation and it would drop back down to 1 ºdkh. Every day it the KH would shoot up for around 8-9 hours, then come back down. This creates a very unstable environment because of PH swings (GH staying the same, KH shooting up and down) which stresses out the plants and fish and excites algae growth. So, how does one fix this? I started using RO/DI water (reverse osmosis and deionized), which removes 99.9% of everything from the water, so my GH and KH are virtually at 0º. I then add Seachem Equilibrium, to get my GH back up to around 4º (or around 71.6 ppm). And baking soda to get my GH to around 4º. Some plants like harder water, some like it softer, so again where you keep your tank depends on the plants you selected.
What I would recommend is testing your tap water to see what you get out of that. If its close to 6º-8º GH/KH, I would try to avoid using RODI water and select plants that will thrive in those conditions. Remineralizing and buffering 100% RODI water is nice, because if you’re a control freak like me, you can get everything right where you want it. But it is another cost to manage, and if you can avoid it and just use your tap water, why not?!
If you just need a little bit of RODI water to dilute (aka “cut) your tap water, most local fish stores sell RODI water and canisters to transport the water in. However, if you plant to go full RODI, I found a great little product called the Aquaticlife RO Buddy. It's compact and inexpensive to run. You can choose to go with just the RO system which is the 3-stage filtration. RO removes up to 99%+ of dissolved salts, particles, colloids, organics, bacteria and pyrogens from the water thus greatly reducing the GH of our water and softens the water to somewhere around 2º. Deionization (DI) refers to the removal of elements like Chlorides, Sulfates, Nitrates, Carbonates, Silica and Hydorxyl which some of the mentioned, in small and large quantities, can be harmful to fish and plants. However, it also removes helpful elements like Calcium, Magnesium, Iron, Manganese, Sodium and Hydrogen. These are macro or micronutrients for our plants and fish need to survive. So again, make sure you are remineralizing with something like Seachems Equilibrium for GH boosting, and/or baking soda to for KH boosting. There is a link to the RO Buddie at the bottom of the page.
If you are interested in what your tap water has in it, the EPA requires local governments to publish what is in your tap water. You can find your city or town here.
Another big thing to address is “cycling a tank” which is the natural process where good bacteria in our tanks turn ammonia into nitrites, and then nitrites into nitrates. The problem with new tanks is they are void of this good bacteria. So if we toss a bunch of fish in the tank without that supporting bacteria, ammonia builds up from the fishes organic waste and gets to a point where it will kill them. Yeah, no fun. So we need to slowly introduce ammonia through adding 1-2 small fish, or throwing a couple of pellets of food or blood worms so they can decompose into ammonia. Once we start the process the ammonia will help stimulate the growth of ammonia-eating bacteria in your tank, from there the bacteria processes the ammonia, into nitrites. Then the nitrites in the tank help stimulate the growth of nitrite-eating bacteria, and these bacteria process nitrites into nitrates…and that is the end of the cycle. Now after about 4-6 weeks of steadily adding small amounts of ammonia, we have enough good bacteria to start adding fish into our tank because it will safely process ammonia into something that less harmful to our fish and plants, nitrates. We do want nitrates in our tank because this organic form of Nitrogen is a nutrient required by plants. However, nitrates are not good for plants and fish in large amounts, like 50, 80, 100ppm+ (similar to how humans can overdose on something that is good for us, like iron) so we need to get rid of any excess nitrates. This can only be done through water changes. When keeping a high-tech tank we are needing to process weekly water changes anyway due to build-ups of fertilizer, so this will just be a part of your routine and you won’t really have to think about it.
When starting an aquacape with aquasoil, it will naturally leach ammonia into the tank for the first couple of weeks kick-starting the cycling process. This prevents you from having to put fish in prematurely at the risk of them dying, or wasting fish food. After about 2-4 weeks you can start adding in some algae eating fish to help keep algae at bay while you tank is maturing.
The two best ways to add oxygen into our tanks is through surface agitation and airstones. The most obvious reason why good oxygen levels are needed is for our livestock; like fish, frogs, shrimps, etc. A less obvious example of would be organisms we cannot see, like beneficial bacteria that live in our substrates, bio media and on our glass. Having the outflow of our a canister filter rippling along the water’s surface can be more than enough to keep optimal oxygen levels in our tank, however, we can sometimes get a biofilm that ends up building up on our forming on the surface of our water. This barrier prevents vital gaseous exchanges from taking place which can reduce oxygen levels and cause certain types of algae like brown algae. This naturally forming Biofilm can be corrected by purchasing a surface skimmer. Also, if we an injecting Co2, while we are getting the right saturation figured out, we can have too much Co2 in the water column which can cause our fish to gasp for air. This can be rectified by letting our filters outlet splash a little on the surface of the water, or by adding an airstone into the water. Regardless of the tank size or setup, I would always recommend some sort of surface skimmer or a tank that has a built in sump in the back that acts as a surface skimmer. Fluval sells a great little $10 attachment that can be fitted to many canister filters to help with surface skimming.
Filtrations is all about mechanical, biological and chemical filtration. Check this video out on how to select a filter and how to set it up to have crystal clear water!