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DamianWarS 09-23-2009 07:07 PM

green tank randomly cleaned itself
i have a 30 gallon take. I do 5 gallon water changes and test the ph and ammonia levels. the ph and ammonia are always the same, ph is always usually 7.2 but has been 7 the odd time and ammonia 0. I only have the kits for testing the ph and ammonia so i don't know what the other levels are (to be honest i really don't know what the other levels mean)

a few months ago the water started to turn green and it seemed it didn't matter how many water changes i would do it would remain green. the ph and ammonia levels were always the same and my fish, when I could see them were alive and seemed well. From the research I could find it suggested the it was some sort of algae bloom and it is not harmful for the fish. I finally gave up on the battle and just thought i would always have a green tank. I kept up with my weekly water changes and and testing the water condition but just let the green water be .

well a couple of days ago I noticed the tank appear clearer than it has been. then a few hours later it appeared even more clearer. When I woke up the next day the tank was perfectly clear and had no green colour in it at all. It just seems in a matter of hours the tank changed. I did a water test and still ph 7.2 and ammonia 0. I was finally able to look at my fish and they all seem fine even though I haven't seen a lot of them in months.

So I was just looking for a reason of why this happened? And is there another level that i should be testing for that can help control things like this? What level should I test for?

Lupin 09-23-2009 07:15 PM

Welcome to, Damian!

I suggest you get a nitrite and a nitrate test kit by API. Here's the excerpt from my goldfish article.

The water parameters must be given of utmost important so pay attention to this as this may seem complicated to those unfamiliar about it. Nitrogen cycle must be considered when starting a tank setup. Why is that? To explain this, the wastes produced by the fish serve as ammonia source. Without the Nitrosomonas bacteria that converts the ammonia into nitrite, the ammonia will simply elevate dangerously thus the fish suffers ammonia intoxication as indicated by listlessness, gill burns, “peppering” or development or black spots, clamped fins, gasping for air on the surface, red streaking on the fins and extreme flashing around due to burns suffered. The next thing that will develop after Nitrosomonas bacteria, is Nitrobacter bacteria. This other strain of beneficial bacteria helps covert nitrite into nitrate, although nitrate itself is not the final byproduct of the nitrogen cycle yet. Nitrite is another dangerous substance that can also cause the fish to become intoxicated. Usually, most references will cite the use of sodium chloride to battle the nitrite intoxication as chloride ions can inhibit the toxic effects of the nitrite however dechlorinated clean water will help equally as it reduces the nitrite thus preventing possible intoxication. In the end, you want to make sure you have zero ammonia and nitrite with nitrate not exceeding 40 ppm if you are keeping fish in your tank. Ammonia and nitrite exceeding 0.25 are highly toxic especially if the pH is alkaline (more than 7) as the ammonia’s toxic effects were not deactivated by converting it into ammonium which only happens when the water becomes acidic (lower than 7). High nitrate level is a result of wastes building up and is extremely dangerous as it can push the fish’s immune system to a breaking point that they become susceptible to health issues and become easily stunted as well.

It has already been noted that nitrate is not the final byproduct yet. This is especially true as most of us tend to forget the nitrate will simply remain in the water elevating dangerously if not for the anaerobic bacteria (anaerobes) that help convert nitrate into the last byproduct, nitrogen cycle. So how do we culture the anaerobes? Simple. In freshwater setups, we do not whereas in saltwater setups, we do using deep sand beds. Why not? Anaerobes form best in dead areas of the substrate and filtration (especially during long power outage periods). Once the organic matter has accumulated and bound tightly where the anaerobes thrive, hydrogen sulfide also forms. Hydrogen sulfide is an extremely powerful acid capable of performing pH steep dives which is extremely dangerous to the fish. As it also reeks of rotten egg odor, the acid can also pose a health hazard to the owner himself and thus is best avoided. A safer way to utilize the anaerobes is by using denitrators where the anaerobes colonize. The water containing high nitrate content is passed through the system where the anaerobes then convert the nitrate into nitrogen gas. The use of denitrator however is not necessary as water changes and use of plants will help reduce the nitrate which is why the use of plants and water changes is widely encouraged. More options and information are covered here.

To be able to determine the exact ammonia, nitrite and nitrate levels, please be sure to invest yourself in a liquid test kit (Aquarium Pharmaceuticals in particular). From this point, biased views will be displayed towards the use of particular test kits. Why? Unfortunately, most test kits manufactured by some companies are none to reliable especially test strips and we are hoping as responsible hobbyists to point everyone new or returning to the hobby in the right direction and as much as possible, minimize the probable issues that may happen. Although, in some cases, test strips have shown their reliability, in general, they tend to be rather misleading and do not give assurance to the owner that the water conditions are within expectations, therefore, these must be avoided altogether. If you can trust your stores to test the water sample for you, this is fine but be sure you understand what they are talking about. Purely comments such as “fine” are very vague. You need to make sure their test kit is a reliable brand, within expiration date and in good condition (albeit not contaminated or tampered with).

The last variables not explained well yet are the pH, KH and GH although the pH has been mentioned a couple of times in conjunction with the toxicity level of ammonia as ammonia is readily influenced by the alkaline or acidic state of the water. Although goldfish have shown to be rather adapted to various water conditions due to generations of selective breeding in the trade for decades, they still are found to do better in hard alkaline water than in a soft acidic environment.

Green water is often a cause of high nitrate and phosphates along with excessive lighting. I actually have no luck growing green water in my tanks except ponds due to insufficient lighting conditions. I know I always have a knack for being a little thrifty with my electric bill.;-) Aside from that, fast growing plants such as Egeria densa and water lettuce help a lot y outcometing the green water completely for nutrients.

Green water has no lasting harm done except that excessive green algae also does respiration process during the night and may compete directly with fish for oxygen. That is the only trouble with green algae especially if oxygen is not maximized. When the algae dieoff begins, more oxygen is consumed during the decomposition stage. This is why in green tanks, over 80% of the green water has to be replaced from time to time while retaining a smaller percentage to serve as green water seeding for those who want to maintain their tanks green.

DamianWarS 09-23-2009 07:28 PM

thanks for the reply. what should the levels of nitrite and nitrate be? my ammonia levels have always been 0 but since I don't test nitrite and nitrate i really have no idea what they have been. Can my ammonia levels and ph be fine but the nitrite or nitrate be off?

Lupin 09-23-2009 07:39 PM

Nitrite should remain zero as it is also as toxic as ammonia especially when your pH and temperature together are high. Nitrate should not exceed at least 20 ppm.

Actually, pH is not always the issue. It is KH and GH that are as these are the buffering properties that help stabilize the pH itself. As long as your hardness levels are high, your pH will remain stable. Check the KH and GH and if low by about 3, you may need to increase it a bit to prevent your pH from dropping steadily. High nitrate also influences the pH and make it more acidic especially if your hardness levels are very low (albeit soft).

DamianWarS 09-23-2009 07:55 PM

well my pH has always been very consistant so I gather that means their buffering properties are fine as well. the pH mainly is 7.2 it rarely is 7 and sometimes has gone a little higher. so testing kh and gh doesn't seem like its going to help me. For that matter my ammonia levels have also always been at 0. I don't care about kh and gh but can the nitrite or nitrates be off and my ammonia levels be stable. If so what is considered toxic to the fish?

Lupin 09-23-2009 08:10 PM

Well then, check the ammonia toxicity table.
Ammonia Toxicity

MoneyMitch 09-24-2009 01:06 AM


Originally Posted by Lupin (Post 247592)
Well then, check the ammonia toxicity table.
Ammonia Toxicity

great great link Bookmarked.

Romad 09-24-2009 05:19 AM


Originally Posted by Lupin (Post 247592)
Well then, check the ammonia toxicity table.
Ammonia Toxicity

Great link. Thanks.

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