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How to easily setup and effectively treat algae problem in a 120p aquascape tank

How to easily setup and effectively treat algae problem in a 120p aquascape tank

Mar 10, 2021

Cheng Hoo Sew

So I finally decided to scape our 120p aquascape tank. This time I wanted to do something simple and conventional. Unlike the rest of our display tanks, this has smaller hardscape at the front which slowly builds up to the tall ones at the back.

For the substrate, I used SL Aqua soil because the usual Fluval Stratum that we use was unavailable when we were setting it up. SL Aqua soil is made for shrimp-keeping and therefore it will have low to no presence of ammonia. But we shall see how that turned out later. Early disclaimer, I didn’t use the ADA method of adding their crushed carbon or bacteria starter powder at the base of the tank, nor did I have stones to house bacteria (Power Sand).

For this tank I've already decided to use these very beautiful blueish light grey stones with some white lines as the main hardscape. We got this stock years ago once and it’s not available anymore due to its very high price. The problem was that since these are leftover stocks, we didn’t have an abundance of them, which made scaping challenging. I used another type of stone which has somewhat the same colour hue but lacks the texture for complete substitution, so they are smaller in size and only used in small quantities. After all, we should never, ever mix stones for hardscaping as the result will look unnatural.

Scaping with the lights on is a good practice as it will give you a better idea of how the scape will turn out to be. I used the NemoLight S72 for this tank. I tested with just 2 lights initially, but did add another one afterwards—we'll get to that later.

NemoLight S72 for Aquascape

Sometimes when I'm decorating a more complicated scape, I will glue the hardscape to the aquarium but in this case, I put the soil in first. This will be a typical design where there's hardscape on both left and right sides of the aquarium. I started by picking the most interesting rock which we may refer to as the main rock. Needless to say, the main rock needs to be the most beautiful and the largest rock. After selecting the main rock, I chose a supporting rock. A supporting rock is a rock that would complement the main rock but should never be considered as its equal.

After placing most of the rocks in the tank, I realised that we were running out of the same type of rocks I was using. To solve this problem, I added some wood to the decoration. While arranging the hardscape, it is very important to make sure the formation is as natural as possible and has harmony within its composition (avoid exact symmetry).

We filled up the tank with water and ran the filter for a couple of days to cycle the tank with Aquavitro Seed. We did a couple of water changes as the SL Aqua soil affected the water more than expected, but not as much as ADA soil would. I would have liked to cycle the water longer but some of the plants that I ordered from Taiwan had arrived and they were not in a very good state.

Plants are arranged by having the shortest ones at the front and then the fast and straight-growing types at the back. When planting in a scape that is designed with formations on the left and right, we need to make sure that most of the plants are planted on both sides to reach a harmonious and natural effect.

I was planning to use Ludwigia arcuata and Rotala macrandra but unfortunately, they were unavailable. I replaced that combo with Rotala macrandra red and Rotala macrandra green. I still might change them if I don't like how the overall look turns out. One tip for beginners is to try to plant as many plants as possible in the tank.

As for the equipment, aside from the NemoLight S72, I'm using a Fluval 406 with Seachem Purigen in it for filtration. I'm also using a Fluval surface skimmer. Part of the reason for that is I've lost the intake pipe and I don't really like using the glass intake as it reduces the flow of Fluval filters. As for CO2 I have a 2L steel cylinder with an Intense Expert regulator along with an Intense check valve, and a XL bubble counter. I got a sample unit of a Neo diffuser and I'm using it on this setup. The Neo diffuser has a very simple design with a unique feature whereby you can bend the pipe to whichever way you want by heating it up. The bubbles that it creates is rather good. Its performance is equal to an ADA diffuser but not as good as an Intense one. I raised the potassium to 20mg/L with Aquavitro Carbonate. I also use a single dose of Aquavitro Synthesis every week.

On the first few days, the tank was doing great but when I came back during Chinese New Year, the tank didn’t look so good. It had a rather high NO3 level which was above 10mg/l but not by too much. I suspect that it came from the SL Aqua soil which might have contained some ammonia, however it isn’t at an unacceptable range. If I didn't introduce Aquavitro Synthesis so early, the NO3 level should have been lower. Normally I would keep my NO3 level at 2mg/l, which is around 5mg/l of nitrogen as Synthesis doesn't use a single source nitrate as its nitrogen.

The main problem was the carbon concentration because the old regulator that I'm using is faulty. The gas release would slow down over time and cause the CO2 in the tank to drop below 20mg/l. Therefore, the high NO3 level was probably caused by the low CO2 level. Other than that, I also found that the lights were not strong enough. 2 lights would be considered alright for a tank with mainly low light plants, but for this one we needed 3.

Salifert CO2 tester

After replacing the faulty regulator, within a few days I noticed that the CO2 release speed dropped again. I concluded that the L size Aquario Neo Diffuser was not large enough for my tank. I was told that it will support a 4ft tank, but problems will start if it’s being used in an aquarium with water surface movement. In my case, I have a surface skimmer installed. That created extra surface turbulence which enhanced oxygen absorption into the water, thus releasing CO2 back into the atmosphere. This means that my tank would need much more CO2 injected to it compared to a same-size aquarium with less surface turbulence.

Unwilling to dispose of a perfectly working diffuser, I decided to run the tank without a surface skimmer. If I'm able to keep the tank healthy enough I wouldn't need one. But unfortunately I still ended up replace the CO2 diffuser. It is just not large enough for this tank size. I would say it will work on a 90p aquarium at most.

After a week, the plants seemed to regain health. This was a good time to get rid of the algae. I used 3ml of 6% hydrogen peroxide per 10L of aquarium water. After couple of days the algae started to turn white. So then I did an 80% water change and added 3 silver flying fox (algae eaters). 


Some algae remain on the lilaeopsis brasiliensis after adjusting the CO2 and hydrogen peroxide treatment.
I'm glad that the hottonia palustris made a full recovery. Was looking for this plant for years.
Pantanal red pinnate looks amazing under the Nemolight s72 light