What means to use to combat lower algae.
To be continued…
If mechanical and biological methods of combating algae do not help, you will have to use chemical agents. Despite the fact that chemical agents are the most effective of all available methods, it must be recognized that remedies that can help aquarists in all cases have not yet been found. The issue of combating algae is one of the complex problems of modern aquaristics. Therefore, one should not forget about the preparations for the destruction of algae offered by specialized trade.
However, using them, one must also take into account the fact that the destruction of lower plants does not exclude harming higher plants, that is, our aquarium plants. The latest generation algicides, when properly dosed, inhibit the growth of green and some other algae. However, all these remedies cannot cope with “black beard”. In addition, the use of antibiotics in the aquarium is dangerous because it leads to the death of first all beneficial aquarium microflora, and then to dangerous diseases of higher plants and fish.
In the case of “water bloom”, a folk method has proven itself well – for 3-4 days the aquarium is completely closed from the light, at least with a blanket, and water is not changed. Fish and higher plants, as a rule, tolerate such darkening quite well, and algae die in the dark and in the absence of a fresh food supply. In addition, if possible, it is good to introduce a large number of Daphnia, Cyclops, which feed on these algae. Besides, medications such as bicillin-5, trypaflavin can be used.
Fairly universal means of combating algae (algicides) are copper or zinc compounds, which are introduced in the form of salt solutions. A solution is prepared from chemically pure or analytical grade copper sulfate at the rate of 1 gram of sulfate per 1 liter of water. Having previously removed fish from the aquarium, it is added to the water at the rate of 1–10 ml of solution per 1 liter of water. Start with a weak concentration, and if there is no result, increase the dose. Thus, it is easy to get rid of blue-green algae and “vietnam”. Copper and zinc also destroy brown algae. Their effect on filamentous green algae is less effective.
The concentration toxic to algae also has a detrimental effect on some plants and snails. Fish should be temporarily removed during treatment. For control, you can add a solution of trypaflavin or rivanol (0.1 g per 100 liters), streptomycin (3-5 mg/l) for 5 days, penicillin (300-600 units/l), 3% boric acid solution (1 ml per 1 liter) to the water. Against blue-green algae, a positive result is given by the use of penicillin at a dose of 10,000 units per liter. Algae die within 8 days. Fish and plants do not suffer.
Combating algae with hydrogen peroxide. There is a chemical that is best suited for use in an aquarium. It is cheap, sold 
in all pharmacies without a doctor’s prescription, and everything this reagent consists of is water and oxygen – hydrogen peroxide. The concentration of the hydrogen peroxide solution that we can find in the pharmacy is usually 3%. This is precisely the concentration that is best suited for use in the aquarium. The dosage of hydrogen peroxide is 0.05-0.4 of the aquarium volume (aquarium volume in liters x 0.05 = daily dose, ml). For 3% peroxide, this gives 1.5-12 mg/l. Hydrogen peroxide at such a concentration is completely safe for the bacterial colony in the substrate and filter.
A rather effective and safe way to disinfect plants from fish diseases and destroy absolutely all algae, even vietnam. The dose is 1.5 mg/l, 6-10 mg/l is also possible. Common algae, like hair algae, die immediately, while black beard requires repeated treatment the next day and dies off within a few days. The use of chlorine bleach is much more toxic and traumatic for plants and fish. Peroxide can also be used to treat the entire aquarium in combination with the darkening method. Create strong water circulation, and a large water change is done a few hours later.
Concentrations up to 15 mg/l for 48 hours are considered safe. At such concentrations, it is completely safe for the bacterial colony in the substrate and filter. Fish usually tolerate a dose of 30 ml per 100 liters without harm, but peroxide quickly oxidizes a lot of organics, which almost instantly removes all oxygen from the water, so monitor the fish, use strong current and aeration! If bubbles appear on filter sponges, aquarium walls, fish, and plants when using peroxide, it means the dose was too high. Only barely noticeable bubbles on mechanical filters are acceptable.
Do not leave the aquarium unattended. If the fish begin to breathe very heavily, immediately change 50% of the water and turn on powerful aeration. Another danger of high doses of peroxide with a large accumulation of algae and/or old organics in the aquarium is a large release of ammonium NH4 / ammonia NH3 and nitrites NO2 immediately after applying the preparation. This can cause fish death. In this case, nitrate and phosphate pollution of the water should be reduced before application. It is better to apply a dose of 6-10 mg/l, create a strong current with aeration, and change 50% of the water in a few hours. During the application of the product, remove dying algae as much as possible and change the water more often and in larger amounts.
If there are favorite plants in the aquarium, you should not exceed the dosage of 20 ml per 100 liters 1 time per day. Exceeding the dose of 15 mg/l of peroxide will kill many stem plants with finely dissected leaves. Hard-leaved plants can be bathed several times in a separately prepared peroxide solution of 40 ml per 100 liters for 40-60 minutes. The effect of glutaraldehyde on stem plants is milder. Attention cichlid keepers! At high pH (>7.2-7.5), the effect of peroxide is more dangerous, because at high pH a significant part of ammonium NH4 is converted into ammonia NH3, which is tens of times more toxic!
Using chlorine. Bleach (“Belizna”) has an unpredictable concentration of active chlorine, depending on the greed and/or negligence of the manufacturer and the time and storage conditions. It 
is diluted 1:30. A leaf overgrown with “beard” is taken and kept in the solution for two minutes. If the algae turned white during this time, I boldly diluted it four times. A sufficient concentration is when after a two-minute treatment and a half-hour rinse, the color of the “beard” does not change. But after the second two-minute exposure, it begins to lighten. In such a solution, bathe the leaves for one minute once, avoiding getting bleach on the roots. Vallisneria and Sagittaria may or may not die even after such treatment. Najas and Ceratophyllum always die. Echinodorus parviflorus, if it survives, withers. Bacopa, Rotala, Hygrophila, Limnophila aquatica, Echinodorus tenellus, Anubias endured without visible changes.
Glutaraldehyde. A great helper in maintaining a planted aquarium is glutaraldehyde. It is not only a source of CO2 for plants, smoothing out concentration fluctuations (which stimulate algae growth), but also a very strong and completely harmless algicide (kills algae). By adding it to the aquarium, you will regularly suppress algae, while “getting the hang of” entering the correct fertilizer dosages, controlling CO2 supply, and getting used to the discipline of water changes and timely plant trimming. Once you learn, you will only need it to speed up getting rid of algae right after starting a new aquarium, or you won’t need it at all.
Recently, Seachem Flourish Excel (glutaraldehyde) has started to be used to combat algae and, it seems, works very well against certain types of algae. To deliver a strong blow to algae, you can dose according to the instructions, or twice or three times more for two weeks. Excel mainly kills red algae, but also has an effect on Cladophora, Staghorn, and hair algae.
Excel negatively affects some plants – Egeria densa, Riccia, Vallisneria. Some report the effect of Excel on shrimp and Otocinclus. With proper dosage, glutaraldehyde will help get rid of all algae, even in the most severe cases, without any harmful consequences for most higher plants, fish, invertebrates, and without harming biological filtration. Another important factor is that the introduction of glutaraldehyde does not affect the pH of the water in the aquarium.
A 2.5% solution of glutaraldehyde is used as the active ingredient – a complex organic substance usually used in medicine and dentistry for cold sterilization of instruments, as well as in the preparation of specimens for electron microscopy. It is precisely the strongest antiseptic properties of glutaraldehyde that apparently provide the algicidal effect. Glutaraldehyde is suitable both for long-term use in a general aquarium and for a one-time pre-quarantine treatment of plants in order to get rid of algae, snails, their eggs, or various pests. An additional advantage of this method is that glutaraldehyde is a reducing agent and helps protect iron from oxidation.
Glutaraldehyde initially becomes very active, but quickly loses activity over time when a special activator substance supplied in a separate jar is added. Activation is necessary only for the sterilization of medical equipment; when used in an aquarium, we do not need it, and the 2.5% glutaraldehyde solution itself can be stored for 2 years. So, having bought a 5-liter barrel of Cidex (it is important not to make a mistake here – there is also Cidex OPA in which a completely different active principle is used instead of glutaraldehyde), it can be stored indefinitely.
With daily addition of 5 ml per 100 liters, noticeable death of algae living in the aquarium in large quantities does not occur. All fish feel great. I think this dose can only be used as a prophylactic. With daily addition of 12 ml per 100 liters for 7-10 days, green algae disappear. The aquarium walls are practically overgrown with nothing if there are no blue-greens. The fish feel great. I believe that such a dosage can be used for a long time.
With daily addition of 20 ml per 100 liters for 5-7 days, all algae die, except for bright green and black blue-green algae. Some fish begin to show mild signs of oxygen starvation within 3-5 hours after applying the preparation. I will add that fish tolerate large doses of glutaraldehyde much better if administered not all at once, but gradually. If the goal is to combat algae, usually half of the daily dose is added immediately, and the rest via a drip system over several hours.
Cidex is added every morning when the lights are turned on (glutaraldehyde in the aquarium breaks down by 50% in 12 hours, disappears completely after 48 hours), having been pre-diluted in a liter of water and mixed intensively when pouring so as not to burn fish and plants. The optimal dosage for long-term use is 12-15 ml of Cidex daily for every 100 liters of water in the aquarium.
The maximum dose – 20 ml per 100 liters – may be needed for particularly severe infestations. When using high doses of Cidex, it is advisable to increase aeration. At the specified dose, there is no harmful effect on fish, invertebrates, plants, and biofiltration. It can also be used to disinfect newly acquired plants and clean them from algae. Rinsing in a bath at a dosage of 1-3 ml per 1 liter of water for 3-5 minutes.
The effect of using glutaraldehyde is as follows: the “beard” changes color to an unhealthy grayish color within a few hours after the first application; 7-10 days after regular application, almost all algae disappear completely, and you also have to clean the aquarium walls much less often. When the recommended dose is halved, the small beard in a strong current tends to appear again slowly. When the dose is restored to standard, it quickly disappears.
Methods of combating lower algae. To be continued.
