Fertilizer Problems / Green Spot Algae

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crimsonpython24

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This conversation originated from this thread, but I moved the discussion here since it's becoming more of an algae problem.

Tank setup:
  • eight danios, two amano shrimps, two bristlenose catfish, and one albino cory catfish
  • 10-gallon tank
  • water temperature: 24-26.5 degC (75-79.7 degF)
  • currently lights on about 9.5 hr/day
  • hardness/pH/ammonia/nitrate/whatever test kits: haven't had them yet
  • fertilizer: npk booster, recommended dosage once per week
  • images of the live plants: (about the weird thing on top, there's a fan in the back to reduce the temperature; in the meantime, I must prevent danios from jumping out. That's the solution I came up with. The light is underneath the "roof." Air comes out through the front)

A few questions here:
  1. How dense should I plant my plants together to prevent algae growth? Are floating plants necessary to control algae growth?
  2. How much phosphate (as in plant fertilizers) should I add to my aquarium? They may be beneficial for the plants but also harmful to the fish. The balance is awkward: I've heard that too many phosphates will lead to blue-green algae, while too little will lead to green spot algae. Should I grab a phosphate test kit or something to measure the level as (like my previous shrimp tank) green spot algae is starting to grow?
  3. What types of nutrients should I add to my aquarium? Tank setup details are provided above.
  4. Will excess iron accelerate the growth of hair algae? I've had recommendations that I should turn to an iron-based fertilizer, but it seems like I'm lacking phosphates at the same time (assuming that #2 is true). I have dealt with hair algae before but I suspect that's more of an over-lighting problem.
  5. Do I over-light? I'd assume that the answer is most likely yes, but I'm not sure the minimum amount of light my plant and fish need.

Thanks in advance.
 

Byron

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How dense should I plant my plants together to prevent algae growth? Are floating plants necessary to control algae growth?

Yes, floating plants can often help. The aim though is to provide the level of light intensity required by the specific plant species, and then balance that with nutrients (which come from fish, fertilizers, organic decomposition, etc). Light intensity and spectrum both matter; once that is settyled, the duration can be used to achieve minimal algae.

How much phosphate (as in plant fertilizers) should I add to my aquarium? They may be beneficial for the plants but also harmful to the fish. The balance is awkward: I've heard that too many phosphates will lead to blue-green algae, while too little will lead to green spot algae. Should I grab a phosphate test kit or something to measure the level as (like my previous shrimp tank) green spot algae is starting to grow?

Assuming this planted tank is intended to be a low-tech or natural method, not an aquatic garden, and fish will be included and will be fed normally, there will be more than sufficient phosphate from the fish food. Fertilizers that do not contain phosphate are OK. The link to the NPK you gave even says this:
The addition of N – Nitrogen (Nitrate) and P = Phosphorus (Phosphate) is not necessary in normal community aquariums, because these substances usually end up in the aquarium in sufficient, or often even too high, volumes via the food.​

Problem algae is caused by an imbalance of light and nutrients, nothing else. If the light intensity and spectrum are adequate for the specific plants, and adequate nutrients are in balance, the plants will use the light and nutrients and algae will be disadvantaged. If the light is on for a longer period than what is balanced, algae can take advantage.

What types of nutrients should I add to my aquarium? Tank setup details are provided above.

A comprehensive fertilizer supplement may be required. It depends upon the plants, fish load/feeding, GH. Never dose individual nutrients like iron, nitrate, etc, as these are not necessary in a tank with fish and they will cause problems.

Will excess iron accelerate the growth of hair algae? I've had recommendations that I should turn to an iron-based fertilizer, but it seems like I'm lacking phosphates at the same time (assuming that #2 is true). I have dealt with hair algae before but I suspect that's more of an over-lighting problem.

Yes, too much iron can cause algae, it can also kill plants, and eventually fish. A comprehensive supplement will have sufficient iron in balance to be safe, and effective. And yes, lighting is usually the issue behind problem algae, though not always.

Do I over-light? I'd assume that the answer is most likely yes, but I'm not sure the minimum amount of light my plant and fish need.

We need the data on the light, but it is LED and I am not much help with that. But if the intensity is OK, and the spectrum (high red, blue and green in the white mix), the duration can often be used to keep algae under control. Tank lighting can be on for six or seven or eight hours (in one continuous period) each day, or longer...depending upon that balance. My tanks have 7 hours daily, and algae has never been an issue since I worked this out.
 

Stan510

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You can have green spot and BGA at the same time,no doubt about that. GS is much easier to eliminate than BGA and GS doesn't damage plant growth like BGA can.
A stable aquarium,less light than what caused the spot algae outbreak will work and fast.
BGA,..when you have high light and many fish in the plant tank? Bad combo. In that case,you really should thin out how many fish since that means less food going in and with also less hours of light and regular water changes will have an impact even on BGA.
A less organic soup aquarium is one free of blue green algae.
 

BluewaterBoof

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I know you have a lot of questions about the fertilizers and tank setup but I highly suggest only adjusting one thing at a time. If you go chasing multiple parts all at once you’re not going to figure out the issue.

I’ve had many planted tanks with all sorts of lights, filtration, plants, and fertilizer supplementation. Based on all of those experiences, length of photoperiod should be your first adjustment when trying to reduce algae. Knock it down to 6 hours. Your plants will be fine with this. Intensity matters more than duration for how the plants will react to the light. If you feel that your light isn’t strong enough, running it for longer does not really make up for the weak intensity. If the light isn’t all that strong then you’re just feeding algae after a certain point.

Anyway, yeah, cut the duration to just 6 hours. If necessary, pick up a cheap wall timer from Walmart for a few bucks. If you’re gone to work/school all day and want to enjoy your tank then set the timer to come on later in the day so that everything is still one and active when you get home in the afternoon. Manually remove as much of the existing algae as you can. Some people use things like toothbrushes for filamentous algae, but I prefer actually rubbing the leaves with my fingers. The finger rub is also pretty effective with removing some of the spot algae, as well. Once all the plants and decor have been rubbed down and the water is all nasty with the crap floating around, grab yourself your siphon and do a large water change and suck up as much of the crud as possible.

Watch the tank for a week and see how things respond. The plants look healthy so don’t worry about changing your fertilizer schedule for now. There are some images on Google that you can pull up to show you what certain nutrient deficiencies look like depending on how the leaves look.
 

StevenF

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You want your nutrients to be in balance with earth other. There are 14 nutrients plants need. Unfortunately you are dosing only 3. Nitrogen, potassium, and phosphate. You are not dosing any calcium, magnesium, sulfur, chloride, iron, manganese boron, zinc, copper, molybdenum or nickel. So the dose of of NPKis likely cause very low levels of some or alll of the other nutrients. So right off the start you are not balanced.

How dense should I plant my plants together to prevent algae growth? Are floating plants necessary to control algae growth?
IN my experience the density of plants doesn't really prevent algae.
What types of nutrients should I add to my aquarium? Tank setup details are provided above.
Ideally all of them. but your tap water likely have some of nutrients you need plus your fish are releasing nutrients in water as they process fish food. So it can be very hard to get them all in balance. And you cannot get cheep test kits that will measure all of the nutrients.
Will excess iron accelerate the growth of hair algae? I've had
Adding any nutrient that is in excess of need and causes other nutrients to be depleted. the resulting nutrient imbalance will fuel the growth of algae while slowing ors toping the growth of plants. One commen recommendation is that you should focus on plant growt. Generally the batter your plants grow the more algae will struggle in the aquarium.
Do I over-light? I'd assume that the answer is most likely yes, but I'm not sure the minimum amount of light my plant and fish need.
Light drives the growth plants and the consumption of nutrients. Too much light can cause a nutrient deficiency which can cause algae. Toomuch can cause unwanted swings in PH. The general recomendation is about 7 hours of lighter day. Preferably only buy lights with a buildt in dimmer so you can adjust the length of time it is on as well as the birghtness.

I have also found it helpful to measure the water PH before lights come on and then right before the lights turn off. When the lights turn of the PH can fall quickly.back to were it started in the morning. A big swing of PH probably means your lights are probablytoo bright or on too long. When I ran into this I saw a PH increase of 2 to 3 points during the day. I dimmed the lights and that kept the PH change to 1 point or less. The PH swine surprisingly didn't appear to aversely affect my fish. None died.

How much phosphate (as in plant fertilizers) should I add to my aquarium? They may be beneficial for the plants but also harmful to the fish. The balance is awkward: I've heard that too many phosphates will lead to blue-green algae, while too little will lead to green spot algae. Should I grab a phosphate test kit or something to measure the level as (like my previous shrimp tank) green spot algae is starting to grow?

I have had Green spot algae currently I have no GSA with no blue green algae. I do have a hair algae issue but it is not growing out of control and shrimp and snails are keeping it in check. I have found that 1ppm of phosphates tends to prevent GSA but on a couple of occasions it got out of control with 1ppm of phosphate. Removing the mulm buildup in the substrate got it under control.

Also when I was new to aquariums I I had plant growth issues and saw a phosphate test kit and purchase it. The Phosphate levels were off the color chart (If I recall correctly the max reading was 30ppm) fish were fine. Why was it so high? I had zero nitrate. Added nitrogen to my tank quickly brought the phosphte levels down and improved plant growth and reduced algae.

So overall I have not seen anything harmful with very high phosphate level and 1ppm of phosphate is not harmful. Currently I maintain a level of 10ppm nitrate, and 1ppm of phosphate. but I could go lower on each in my shrimp tank. As long as you have measurable levels you should be OK. Note the best phosphate test kit on the market is this one. It read 0.1ppm to 30ppm. they also have a low range version that can measure up to 2.5ppm. i purchased the low range version but I don't need the low range. the 0.1 to 30ppm would work just fine. Note exactly cheep at $50 but it is very accurate at low levels. Most low cost phosphate kits don't work well at low levels.
 

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