Continued from page 1How to Proceed?
Whichever method you use (or perhaps you are using a combination of the two that I listed) is not important, as long as you persevere. This approach appears to be the main key in being successful.
The amount of phosphate in the aquarium water may be really high, and as a result, one or two water changes, or one or two treatments with the compounds mentioned are not going to solve your problem based on my experience.
You will need to do either of the following (based on personal experiences and suggestions by manufacturers):
Method 1
- Test your phosphate level and make a note of it (day 1)
- Perform a 10 percent water change (day 1)
- Test your phosphate level and make a note of it (day 1)
- Test your phosphate level (day 2 - 24 hours after the first water change)
- Change another 10 percent of the tank's water (day 2)
- Test your phosphate level after the water change (day 2)
- Test your phosphate level (day 3 - 24 hours after the second water change)
- Change another 10 percent of the tank's water (day 3)
- Test your phosphate level (day 3)
Keep doing so until the phosphate level has dropped and dropped and is in the neighborhood of 0.03 to 0.04 ppm.
As long as it is higher you need to continue to change water.
As you can see this method becomes pretty costly because of all the salt needed, the treated water you use, and the tests you perform.
Note that most tests on the market do not test below 0.1 ppm and that even if your phosphate level is 0.06 ppm (which is too high), therefore your test may incorrectly show that you have zero phosphates.
The reason for this is simple: your test is not sensitive enough to measure below 0.1 ppm and you will, therefore, not get an accurate result.
As you keep performing water changes though, and unless you introduce phosphate in some manner directly to the tank, the levels should go down, and the green undesirable algae that we call micro-algae should start to die off.
Thiel recommends that you siphon these out of the tank. This prevents them from decaying and adding more phosphate to the water (which would lead to more algae growth). I think his suggestion makes sense indeed and do practice that when I experience an algae bloom.
Method 2
This method relies on the use of phosphate-removing compounds, the metal oxides I referred to earlier.
What is suggested is to place a batch of this compound in the tank and make sure that contact between the compound and the water is high. These compounds work like sponges, and in order for them to absorb phospahtes, they need to be in contact with the water or they cannot absorb sufficiently.
Because such compounds become saturated (they can only absorb a certain quantity of phosphate), it follows that they will need to be replaced.
The higher the level of phosphate is that you start at, the sooner you will need to change them in the beginning as the high levels of phosphate will quickly saturate the compounds.
As the levels diminish you will find that they will remove phosphates for longer because they do not saturate themselves as quickly.
How do you know then when to change the compound? Test the water and determine what happens to the concentration of phosphate.
As long as the PO4 ppm level keeps going down, the compound is still absorbing phosphates. When the level stays the same or starts to rise again, you need to replace the compound with a fresh batch.
As I stated, the higher the initial level, the more times you will need to do this. The results of your testing will indicate when you have achieved a low concentration and when you can stop.
Of course, during this treatment period algae will die off, or change color (the green will tend to look less green). Siphon them out to prevent them from breaking down and adding more phosphates to the water (as this would give rise to more algae).
When either all algae have disappeared, or when the phosphate levels are low enough, put in a fresh batch and leave it in the tank so it can absorb whatever phosphate is being produced.
At some point your tank will be free of algae, but how many changes of compound this will take is hard to tell as it depends on each individual situation and how much phosphate there was to begin with.
Method 3
This is a simple method and relies on adding hermit crabs to the tank that consume the algae as they grow. This is a bit of a "patch method" since you are dealing with the outcome (growth of algae) and not with the cause (too high levels of phosphate).
How many hermit crabs are needed depends on the size of the tank. I do not know if there actually is a correct way to gauge this, but my suggestion is to use about one per 20 liters of water (ed. note: about 5 gallons).
If that amount of herbivorous hermit crabs does not keep the growth under control or eradicate it, you may need to add some more.
Keep in mind though that as the hermit crabs feed on the algae, the amount of algae diminishes and so does the food for the hermit crabs. There comes a point where the amount of algae in the tank is too small to sustain all the hermit crabs you have placed in your tank.
This can pose a problem in my experience. When not enough food is available in the form of algae, some of these hermits start attacking other animals in the aquarium. I have seen these hermits attach to snails and even shrimp. One of the problems sometimes reported is that the hermits attack other animals and are not just herbivorous but may be carnivorous or omnivorous, however this phenomenon may have to do with the fact that they are running out of food.
This could lead to predation in the aquarium because not enough food for all those hermit crabs is available (the first victims appear to be snails).
We may, under this method, have to lower the number of hermit crabs of various kinds to prevent this from happening.
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