Nitrates/algae driving me nuts!!

[birddancer]

Ok, I have a 4 foot tank with;

2 adult breeding Angelfish
4 mixed Corydoras
1 Peppermint Pleco

I've been doing 25% waterchanges every 2 weeks and 50% every month. (and for the past few weeks have done weekely 10% changes). Lately there's been a blowout of this thick fury black algae that covers everything. It grows sort of long a sways in the breeze. LOL. The fish are healthy with the Angels continuing to breed, lay eggs etc. Have treated with algae rid products but mindfull of not going overboard with it and I take out all the wood, ornaments etc and scrub them regularily.

The tank is free of Ammonia, Nitrites and PH levels are stable. But the Nitrates are @ 80 Is this why it keeps re-producing? And how can I get Nitrates down? I thought the amount of water changes would be enough.

[birddancer]

I should also add the lights are on from 7am - 7pm. Is that too much light?

And I'm running fluval canister and eheim internal filters.

[starsplitter7]

Do you vacuum the gravel during water changes? When my nitrates explode, I vacuum the gravel. Half the tank one week, the other half the next.

[Diana]

Beneficial bacteria keep ammonia and nitrite under control by turning it into nitrate.

There are bacteria that remove nitrate, but their side effect is toxic, so we do not encourage them in the tank.

Plants remove all 3 forms of nitrogen. Algae counts as a plant as far as removing this fertilizer.

If you do not want the bacteria that produces toxins (none of us do) and you do not want to plant the tank (ie: you do not like the algae) then YOU will become the nitrate removal system in the tank.

No, your water change system is not doing the job.

Try 50% water changes twice a week until the nitrates are under 10 ppm.
Then monitor the tank to see how long it takes for the nitrates to reach 20 ppm.
That is how often you will need to do 50% water changes.
If NO3 rises from 10 to 20 in one week, then you will need to do 50% once a week.
If NO3 rises from 10-20 in 2 weeks, then you will need to do a 50% water change every two weeks. I would not actually wait that long. I would do weekly 30% instead of every other week 50%. (No, the math is not simple. It is not half as much water change twice as often)

Vacuum all the gravel thoroughly with every water change while you are doing the 50% twice a week. One you have it under control, then vacuuming half the tank with one water change and half the next time will work just fine.

At every water change clean the filter in the water removed for the water change. Once you have the nitrates under control you might find it is OK to clean the filter less frequently, but all the food and other debris that is composting in there is adding to the nitrate problem. The faster you remove it from the system the better.

Feed less. Nitrogen enters the tank as protein. It is good that your fish are spawning. Means they are getting a luxury amount of food. But this also means there will be high levels of ammonia waste, either from the fish or from uneaten food. you are the lean up crew. If you cannot handle the water changes then back way off on the food. The fish will probably quit spawning. Try feeding only half as much food, and only half as often (Yes, this is 1/4 the ration you are now giving them)

Plant the tank. If there are so many plants that you cannot see the back of the tank then they will handle the nitrogen waste. Of course plants have their needs, too. Good light, some supplements to supply the fertilizers that are in short supply in fish food, extra carbon dioxide.

To control the algae:
Less light. If the tank is in a reasonably bright room then keep the tank light off. The fish will have a normal day/night cycle. Turn on the light only when you are there to view the tank. If the tank is in a really dark area then get a dimmer light for the tank. Keep the fish on a regular day/night cycle, but the light does not have to be very bright.

Squirt hydrogen peroxide on the algae. Here is how:
If you can remove the object from the tank, do so. Dip it in a bucket that has a cup (.25 liter) hydrogen peroxide per gallon (4 liters) and allow the object to soak for a few minutes. The algae will turn pink when it dies. You could even spray pure (well 3%) H2O2 right onto the algae while the object is out of the tank.
With the stronger treatment the algae will usually die with just one treatment. If you have to treat in the tank (see next section) it will tank longer.
A rinse to remove most of the hydrogen peroxide, and the object is safe to return to the tank. A trace of hydrogen peroxide in the tank is not a problem.

If you cannot remove the item then do this:
Do a water change.
Turn off filter and any other water movement (power head, bubbler). Put up to 27.5 ml or 5.5 teaspoons of 3% H2O2 in a syringe, no needle, and squirt it on the algae. For a 55 gallon tank, 5.5 teaspoons (27.5 ml) is maximum dose. If the algae is getting kind of long you may not get all of it treated in one day. If the algae is still pretty small, or you have mostly trimmed it off then you will probably treat more of it by squirting a drop or two at each clump. This sort of treatment is safe for live plants, too.
Leave the water movement off for up to half an hour, then turn things on again.
Repeat the next day, but always do a water change before dosing more H2O2.
You may have to hit each bit of algae 2 or even 3 times to kill it.

H2O2 breaks down in light. If you are running a UV, or this is a planted tank with high light, or the tank is exposed to direct sun the H2O2 is more likely to break down in 24 hours.
Since you can never be sure how much has broken down it is much safer to do a water change before dosing again.

[starsplitter7]

Hello Diana,

Just for my own information. I have always been told not to vacuum the entire tank at once to make sure and not remove too much bacteria at once. I know most of the bacteria is in the filter, but I thought a good amount was in the gravel too. I just wanted to make sure it is safe to vacuum the entire tank at one time. Thanks, Tanja.

PS Sorry about the double post. I can't find a button to delete the second one. I didn't even know one message posted, and there were three. Sorry about that.

[starsplitter7]

Diana,

Just for my own information. I have always been told not to vacuum the entire tank at once to make sure and not remove too much bacteria at once. I know most of the bacteria is in the filter, but I thought a good amount was in the gravel too. I just wanted to make sure it is safe to vacuum the entire tank at one time. Thanks, Tanja.

[cloudhands]

The bacteria we want is not so much free-floating, but stuck onto objects. It's not so much loose in the gravel, but adhered to it. Unless you suck up the gravel itself, you're not going to suck up all the nitrifying bacteria that may be associated with it.

[glenna]

Thanks, Diana, for the primer on using H2O2. I know I am tagging on to someone elses post ,but that was PERFECT timing and just wat I needed!!!!!!
ALGEA, BEWARE!!

[mistergreen]

Hello everyone!

I haven't been on here in a long while and I know this algae well. It's called black beard algae. All driving force for algae is light. If you can reduce that, you reduce the algae. Cut down on the hours or loose a bulb.

Another product that can kill the algae is Seachem's Excel. It's a carbon supplement for plants but it also kills algae.

[Diana]

Ditto cloudhands. The nitrifying bacteria is indeed stuck to surfaces, growing in a biofilm with many other microorganisms.

Yes, about 50% or more live in the filter media, and somewhere over 25% live on the surfaces of the substrate. The remaining 25% or so grow on all the other surfaces that meet their needs.

Large, coarse gravel does not have a lot of surface area, but has pretty good water flow. Medium or finer gravel has more surface, but the water flow is more restricted, especially deeper in the gravel.
The water exchange through the gravel brings oxygen and food to the microorganisms, and removes their waste. Under gravel filters were created to take advantage of this, and increase the water flow deeper in, and encourage more bacteria. These were developed before today's large, reliable filters.

Large filter volume, so there is plenty of room for extra sponge, floss and bio media is another way to encourage more bacteria. There is a LOT of surface area on the filter media. As long as you clean it frequently to assure good water flow, and use water from the tank (or at least dechlorinated water) the bacteria will thrive in the filter.

Other ways to encourage nitrifying bacteria:
Moderate pH. 6.5 minimum, but better in the 7s. As high as 8 is not a problem.
Some minerals in the water. Best represented by GH and KH over 3 degrees. There is not really an upper limit. Just different species of bacteria as the water becomes harder, and some salt is present. Such as a brackish water tank, and then a marine tank.
Good water flow for these bacteria is not too fast. That strong a flow starts to damage the bio film. (This is one way water companies keep the pipes clean) One very good way to maintain high water flow for the fish, but not too high for the bacteria is to use a larger filter with a thick mass of sponge and other media, not a thin cartridge. The force of the water is then spread out through the sponge. This traps the debris better, too.
Low light. These bacteria are better in dark places. They are not found in great numbers right at the top of the gravel, but under the first layer of rock where the water flow is still there, but the light is shaded by the top layer of rock.
Minimize the use of antibiotics and other treatments that might slow the growth of the bacteria. This is very important when you are starting a new tank that has not built up a varied population of microorganisms. When the tank is well established (really, the microorganisms are well established) then they are more tolerant of such things.
Side note: this is why some diseases are so hard to kill: the bacteria or other organisms that cause the disease are in a protected film and the medication does not reach them.

[franmorr1966]

I think lights are on too long; but is it because you're trying to simulate breeding conditions?

I believe in siphoning the gravel, I do that every time I change water. I used to do 50% changes every week but it's easy for me because my tap has no added chlorine so it's one less step I take.

Also rinse the filter media weekly too. It's amazing the crap that gets in there. I think that's a significant thing to do to keep nitrates under control. I had your problem years back.

[palaeodave]

I have black beard algae covering all the big rocks in my hillstream tank and I think it's beautiful. Less beautiful in my Botia tank, where it used to smother the Anubias. Four SAE sorted that out completely. Lovely fish, too.