Need help controlling algae bloom

Hi all.

I am facing algae bloom in a 60 litre (~15 gallon) tank I have. This started about a month back. During weekly water changes, I have used a scraper to clean the glass walls and a brush to clean the hardscapes (rocks) of algae. Then syphon the water and refill with tap water. But within a few days it appears again. Till date the fishes are not effected and there is no change in their behavior, which makes me think that its one of the harmless forms of algae (can attach pictures if that will help better). However, it definitely looks dirty with patches on the aquarium wall.

I do have a high nitrate problem, which is because the tap water I use has nitrate of around 40 ppm. So the nitrate in my tank is always between 20 - 40 ppm. The tank is well planted (2 amazon swords, 1 java fern, 2 vallisneria, 4 argentine sword, 6 water wisteria (1 planted, 5 floating), 1 anubias nana, 2 pogostemon stellata, 4 Cabomba (green). I also added a pothos last week (roots are still establishing). The java fern, amazon sowrds, water wisteria, and vallisneria are growing very well, while the rest are not showing any growth. In fact, it seems the cabombas are dying now. which could be because of the algae? I switch on the light for 8 hours only (and sometimes little less, but never more), which I thought is okay for a tank with this many plants.

Now the question I have is: how do I solve this algae problem? I change 30-40% water weekly and use API tap water conditioner, which however does not help with the high nitrate. Using a chemical to bring algae in control is the last think I want to do (as I have heard that wrong dosage can kill fishes). Is there a balanced and natural way to solve the algae problem? Any tried and tested method that has worked well? Tank might be a bit overstocked, could that be the reason?

Looking forward to help on this. Thanks!

 

use API tap water conditioner, which however does not help with the high nitrate.

Water conditioners are only de-chlorinators. They have nothing to do with Nitrate.

Is there a balanced and natural way to solve the algae problem? Any tried and tested method that has worked well?

Depends completely on the algae.

Tank might be a bit overstocked, could that be the reason?

Maybe. Depends.

So some questions:
- How long is the tank running?
- Do you add any kind of fertilizer?
- What substrate do you use?
- I assume not, but do you use CO2?
- What fish and how many are stocked?
- What's your feeding regimen?
- Can you please post a picture of the tank?

Otherwise let me sum up:
- You do 30-40% waterchanges a week
- You scrub glass and decorations clean.
- Your tap water has 40mg/l nitrate.
- Your choice of plants encompasses mainly slow growers/consumers and low numbers of fast growing plants.
- The light period is roughly 8 hours daily.

I have an idea what might be going on, but it takes the questions to be answered and absolutely requires a picture of the tank to be sure.

I also added a pothos last week (roots are still establishing).

This will be your saviour, so much I can tell already. You grow it emersed, right?

 

Water conditioners are only de-chlorinators. They have nothing to do with Nitrate.

Depends completely on the algae.

Maybe. Depends.

So some questions:
- How long is the tank running?
- Do you add any kind of fertilizer?
- What substrate do you use?
- I assume not, but do you use CO2?
- What fish and how many are stocked?
- What's your feeding regimen?
- Can you please post a picture of the tank?

Otherwise let me sum up:
- You do 30-40% waterchanges a week
- You scrub glass and decorations clean.
- Your tap water has 40mg/l nitrate.
- Your choice of plants encompasses mainly slow growers/consumers and low numbers of fast growing plants.
- The light period is roughly 8 hours daily.

I have an idea what might be going on, but it takes the questions to be answered and absolutely requires a picture of the tank to be sure.


This will be your saviour, so much I can tell already. You grow it emersed, right?

Thank you for the message. Here are the details -

- How long is the tank running: About 4 months now (I use API test kit regularly, and it shows 0 ammonia and nitrite)
- Do you add any kind of fertilizer: No
- What substrate do you use: Its tropica aquarium soil as the base layer, which is fully covered by very fine gravel.
- I assume not, but do you use CO2: No to CO2 (should I be doing this?)
- What fish and how many are stocked: 3 mickey mouse platy (juvenile), 4 dwarf red coral platy, 3 cory cat, 2 dwarf gourami
- What's your feeding regimen: Twice a day. Roughly a gap of 12 hours between feeding. Feed for around 30 secs or little more at time. Gouramis seems to be slow eaters, so it takes around 30 sec or little more at times.
- Can you please post a picture of the tank: Will do this for sure.

Yes, the pothos is emersed. Should I add more? I have lots with established root system, but in soil (garden). In can take those out, wash the soil thoroughly and put it in the aquarium (emersed form) if that will help.

 

picture of the tank and the algae would be great to see what you are dealing with.

THis "I am facing algae bloom in a 60 litre (~15 gallon) tank I have. This started about a month back. During weekly water changes, I have used a scraper to clean the glass walls and a brush to clean the hardscapes (rocks) of algae. Then syphon the water and refill with tap water. But within a few days it appears again."

connected with water changes, getting better initially than worse in a day and onward, settling on glass and hardscapes and running for about a month so far.

I have my suspicion also on what it is, but need to see what it looks like. people generally use "bloom" to describe cloudy water whether it's algae, bacterial or diatom, but the blooms are different colors of cloudy unless it's more than one at the same time.

Anyways a picture of this algae would be very useful to see what it is and what it's doing.

 

picture of the tank and the algae would be great to see what you are dealing with.

THis "I am facing algae bloom in a 60 litre (~15 gallon) tank I have. This started about a month back. During weekly water changes, I have used a scraper to clean the glass walls and a brush to clean the hardscapes (rocks) of algae. Then syphon the water and refill with tap water. But within a few days it appears again."

connected with water changes, getting better initially than worse in a day and onward, settling on glass and hardscapes and running for about a month so far.

I have my suspicion also on what it is, but need to see what it looks like. people generally use "bloom" to describe cloudy water whether it's algae, bacterial or diatom, but the blooms are different colors of cloudy unless it's more than one at the same time.

Anyways a picture of this algae would be very useful to see what it is and what it's doing.

Will surely post the pictures tomorrow. Its night here (almost 1 am) and sleep time for my fishes, so will click and post the pictures tomorrow. Thanks.

 

About 4 months now (I use API test kit regularly, and it shows 0 ammonia and nitrite)

Ok, so you are in the first 12 months. Be aware in the first 12-18 months algae come and go on their own.

- Do you add any kind of fertilizer: No
- What substrate do you use: Its tropica aquarium soil as the base layer, which is fully covered by very fine gravel.

Well, actually, the substrate is full of nutrients. That's probably why the plants don't suck up much nitrate from the water column. -> nutrient surplus.

Makes 2 reasons. Moving on:

- I assume not, but do you use CO2: No to CO2 (should I be doing this?)

Good. CO2 isn't necessary per se.

What fish and how many are stocked: 3 mickey mouse platy (juvenile), 4 dwarf red coral platy, 3 cory cat, 2 dwarf gourami

That is indeed a lot for a tank that size. I would probably rehome the livebearers and stock up the Corydoras to 6 and call it a day. With this stock you will always have trouble in this tank size.

- What's your feeding regimen: Twice a day. Roughly a gap of 12 hours between feeding. Feed for around 30 secs or little more at time. Gouramis seems to be slow eaters, so it takes around 30 sec or little more at times.

And what do you feed? Although here I see the least problematic things.

Yes, the pothos is emersed. Should I add more? I have lots with established root system, but in soil (garden). In can take those out, wash the soil thoroughly and put it in the aquarium (emersed form) if that will help.

Long term this will be the only way to keep your tank in balance. Just make 2-3 more cuttlings.

I have my suspicion also on what it is, but need to see what it looks like. people generally use "bloom" to describe cloudy water whether it's algae, bacterial or diatom, but the blooms are different colors of cloudy unless it's more than one at the same time.

Anyways a picture of this algae would be very useful to see what it is and what it's doing.

Absolutely agree.

Yet, there is one thing that has to be adressed: There is a massive surplus of nutrients from soil, from overstocking and from the nitrates in the tapwater.
Long term all three will have to be solved one way or the other.

 

Ok, so you are in the first 12 months. Be aware in the first 12-18 months algae come and go on their own.

Well, actually, the substrate is full of nutrients. That's probably why the plants don't suck up much nitrate from the water column. -> nutrient surplus.

Makes 2 reasons. Moving on:

Good. CO2 isn't necessary per se.

That is indeed a lot for a tank that size. I would probably rehome the livebearers and stock up the Corydoras to 6 and call it a day. With this stock you will always have trouble in this tank size.

And what do you feed? Although here I see the least problematic things.

Long term this will be the only way to keep your tank in balance. Just make 2-3 more cuttlings.


Absolutely agree.

Yet, there is one thing that has to be adressed: There is a massive surplus of nutrients from soil, from overstocking and from the nitrates in the tapwater.
Long term all three will have to be solved one way or the other.

Wasn't aware of the 12-18 months algae issue. Thanks for this info. Is this the time anaerobic bacteria takes to established? What is the science behind this?

Will rehome the livebearers. But the only spare tank I have right now is a 5 gallon nano tank, that I kept for a betta. 5 gallon I guess would be too small for that many livebearers. The other tanks I have are full.

I feed hikari micro pellets and algae flakes (crushed). I have tried feeding cucumber on few occasions, but couldn't succeed. None of the fishes touched the cucumber slice even after 6 hours, which is when I have to take it out

Will add more pothos, its something I can do easily - I have lots growing in our garden.

I will add photo of the algae patches on glass and hardscape today.

 

Wasn't aware of the 12-18 months algae issue. Thanks for this info. Is this the time anaerobic bacteria takes to established? What is the science behind this?

Experience rather, science for sure too, but I'm not a biologist. In this time frame not only bacteria but also other microorganisms grow to sustainable populations, plants establish firmly and nutrient influx and use clos in on each other.
Also the human factor developes experience with the tank in question and so does the maintenance.

Will rehome the livebearers. But the only spare tank I have right now is a 5 gallon nano tank, that I kept for a betta. 5 gallon I guess would be too small for that many livebearers. The other tanks I have are full.

Until you rehome them, keep them in the tank they are in now. A week more doesn't do much damage.

I feed hikari micro pellets and algae flakes (crushed). I have tried feeding cucumber on few occasions, but couldn't succeed. None of the fishes touched the cucumber slice even after 6 hours, which is when I have to take it out

Unsurprisingly. Cucumber is not on the menu for any of your fish. Once the livebearers are out you can also scratch the algae flakes. Then you have mainly carnivores.

Will add more pothos, its something I can do easily - I have lots growing in our garden.

Perfect. I grow four of them out of my tank up and along the wall of my room.

I will add photo of the algae patches on glass and hardscape today.

And one of the full tank please. The overview is the most helpful picture usually.

 

Here are the pictures.

Hope these helps. Thanks.


Just saw your message on the aquarium picture, will upload it as well - in a couple of hours.

 

That’s diatom algae. Feeds off of silicates leached from the silicone seals on the tank and silica in the substrate. It can take a while to die down, but regular cleaning and biweekly water changes will have it resolved fairly quickly.

not sure why the previous person made it harder than it is. The tank is fairly overstocked but not unmanageable.

co2 Injection actually will solve the issue if that’s the route you want to go. You’ve got a well planted tank that would take off with co2. With the infusion of co2 the plants will pull far more silicates from the substrate and reduce algae significantly.

 

not sure why the previous person made it harder than it is. The tank is fairly overstocked but not unmanageable.

Because I have a different approach. Plus overstocking does not only concern bioload, these fish belong in a bigger dimensioned tank as well.

Also silicone doesn't leach silicates and plants don't absorb a lot of silicates either.

Only thing I can agree on - it's diatomes. They usually go away by themselves in a fairly new tank, if just left alone, after a month or so. It's completeley sufficient to clean the front glass, do regular waterchanges as they are done already and that's it.

Leaves the nutrient overload.

 

Silicone seals do leach silica and every plant on earth needs silica for photosynthesis. Less so in aquatic plants which is why I suggested co2 to increase nutrient usage.

 

Silicone seals do leach silica and every plant on earth needs silica for photosynthesis.

The amounts possibly leached are minute and don't matter.
At which point are silica involved in photosynthesis? I know it's involved in other processes, but this is new to me.

 

No. They’re not minute. Glass tanks are notorious for diatom algae due to leaching alone. Without any plants it can be never ending.

As far as silica and photosynthesis, as I said, aquatic plants are much less relient on it than terrestrial plants but introducing co2 is a sure fire way to allow plants to use any and all excess nutrients at their disposal.

I don’t want to be rude, but I’ve been doing this a very long time. I have a career in the field. Please don’t give advice to someone if you’re not certain.

 

No. They’re not minute. Glass tanks are notorious for diatom algae due to leaching alone. Without any plants it can be never ending.

In many years in the hobby I have not encountered this. Diatomes have never been a problem in any way to me and I only use glass tanks, even had tanks only containing silica sand and sandstone, which didn't develop perpetual Diatome colonies.

As far as silica and photosynthesis, as I said, aquatic plants are much less relient on it than terrestrial plants but introducing co2 is a sure fire way to allow plants to use any and all excess nutrients at their disposal.

That doesn't answer my question, though. I know if you tweak one of the main factors the others have to follow, but where exactly is silica involved in photosynthesis? If you don't want to explain, give me a source to read up.

I don’t want to be rude, but I’ve been doing this a very long time. I have a career in the field. Please don’t give advice to someone if you’re not certain.

I'm certain of what I know, yet missing some information it seems. That's why I'm asking.

 

I see a fair bit of empty space, and between the aquasoil and your tap water, there's a ton of nutrients available. With all those nutrients, and all that space something will certainly grow to fill the void.

So fill in the gaps. Pack that tank full of plants. Better to pack it full now, and trim later as the bigger plants grow in. That way algae never gets a foothold.

The diatom problem will solve itself. But when its gone, something else will take its place. Better that it be plants rather than algae.

 

No. They’re not minute. Glass tanks are notorious for diatom algae due to leaching alone. Without any plants it can be never ending.

As far as silica and photosynthesis, as I said, aquatic plants are much less relient on it than terrestrial plants but introducing co2 is a sure fire way to allow plants to use any and all excess nutrients at their disposal.

I don’t want to be rude, but I’ve been doing this a very long time. I have a career in the field. Please don’t give advice to someone if you’re not certain.

Huh? So what you are suggesting is plants use Silica?

You are suggesting silicone sealant or glass or rocks or sand, that silicon materials are heavy leachers of silica or silicon?
Suggesting that maybe an acrylic tank is diatom bloom proof?
Can you please explain your position on this further? or was it just an oversimplification and over exaggeration?
Which field do you have a career in also? You put that in there to gain credibility for sure, but didn't give enough information on the field to prove it's even relevant.

I don't have a job in this field, whatever field it may be, but I know bologna when I taste it and the claim that glass or silicone sealant leaches more than a minute amount of silicates annually, or even over the course of a decade sounds absurd, as well as fixing nutrient excesses with more CO2 as if you just need to pump in more and more and the problem is eventually solved. it doesn't work like that, there's a balance.

Plants don't use silica at all, microbes use silica, plants use silicic acid that is created by microbes in the soil from free silica for cellular health and chlorophyll production.
Diatoms use (silicic acid) to form their shells (a glass house) that is the method of locking free silica back as unaccessible in the form of their fossils as diatomaceous earth. they consume nutrients like nitrogens, to live and reproduce and bloom.

when a balance is reached, diatom bloom is gone, plants do well, you don't need extra CO2 because there's a balance of plant to O2 and CO2 production and usage. it's the imbalances that cause blooms, diatom, algae, bacterial, ect. and excess nitrates or excess nutrients will be removed one way or the other.

I'm sorry, and not trying to be rude, but I'm astounded by the statements posted about the aquarium glass or the silicone sealant, or the CO2 to fix nutrient excesses.
Most everyone is using some form of treated water devoid of life as a starting point, and natural processes have stopped with it. As water becomes live again, natural processes are restarted, balances must be achieved and maintained, imbalances accounted for. It's got little to do with CO2 amendment, or glass or acrylic and how much silicon source there is because locked silicon is locked silicon, it's not bioavailable.

Most folks don't know what PPM (or mg/L) of oxygen or PPM of CO2 their tank even has over the course of any given day, or how many watts per gallon (wpg) of water of light they have or even need for low, mid or high usage plants, nevermind that it takes microbes they can't even see to make silica bioavailable to plants and diatoms and algae alike.


Ritam23, it's diatoms, it's ugly if you don't clean it off of stuff, but it's not a big deal, it doesn't hurt the fish, it can interfere with photsynthesis of your plants if it allowed to really coat them.
They will settle down eventually but they are exploiting your nitrates in your source water and what the tank is producing, So you are always going to have them to some extent blooming unless nitrates were taken down low to at least end this bloom.

A fix would be, short of finding another source for your tank water, or using RO or distilled water and remineralizing just to remove the nitrates from the source water, it would be planting much more, and trying to get a consumption that uses up the nitrates after each water change, then not changing the bioload to add even more nitrates to the equation.
All in one fertilizers would be bad also, you'd be better served with a nitrogenless fertilizer or one with a really low value. the light is of little consequence and doesn't make much difference in controlling the diatoms, it does help with the plants consuming the nitrogen though.

Or, another option and what I do: no plants, and live with the diatoms and the higher nitrates, clean the glass stir the substrate flip over larger rocks, it comes and it goes, depending on my stocking level.
I don't have nitrates in my source water it's all created in tank, I do build over 100 nitrates in a week from my current stocking level, so I go from 50 to 100+ ppm nitrates with 1 50% change a week, or 25-50ppm nitrates with 2 changes a week and it never hits the 100ppm. getting it lower than that is impossible without cutting the fish I have there.
also not a big deal, water changing every week and cleaning the biggest eyesores. for me plants are just too hard to clean, even the fake plants. I rarely had a bloom that clouded the water but I did get a brown coating on surfaces I like a planted tank, but for what I'm doing, a clean tank and ease of water change and waste removal is more important than pretty, the fish being the main focus for me. My diatoms are always there, there always there in everyone tanks, just more visible in some tanks than others, mine bloom when I change the fish load and the nitrate production changes, when i overstock, or when I down size, pretty much every time I have an imbalance that needs correction for.

your source water nitrates, are basically fertilizer nitrates, no waste decomposition to get to nitrification needed. if you keep plants and like them, I'd think about sorting out the planting level, and methods to fertilize all other nutrients besides nitrogen compounds until you run zero nitrates shortly after water changes, then add a fish or fish, and then more plant to offset their nitrate production. you still can't avoid water changes really. it's just how to deal with the 20ppm nitrates that come with each one and there's a few ways to go about it.

 

Coming back to what MacZ asked for - here is the picture of the full aquarium.

Like MaritimeAquaman suggested, if there is a lot of space left for plants, what plants should I put in?

So what is the solution we are looking at? will this go on its own with regular maintenance and RO water instead of tap water, and more pothos maybe?

Even if CO2 infusion could solve this I understand that means additional equipment, and that is something I am not willing to do currently. So what is the solution around this diatom issue?

 

Hi Ritam23
I have read a little of what’s been written in this thread about the 16 gallon with platies.

I don’t wish to contradict what has been suggested. Please just take what I write as my opinion and a look at some snapshots from a local club members fish room .

I have a few platies myself. I believe one 30% - 40% water change is on the low end of what could be done in the 16 gallon.I would suggest increasing that to 50% with other random small water changes mid week at your convenience. Just try it for a couple of months? That will lower the nutrients/ nitrates in the tank water.

My opinion looking at your pretty tank.
It’s not as bad as it could be .
Post #1 reads like you don’t use a timer on the lights? If so you could get one?
I think I recognise that light bracket? If it’s one of the ones that allow the percentage of light to be turned down do so by half. If not raise the light as high as possible. A lid would help defuse some extra light.
Fast growing plants with their leaves in the air consume the most nutrients. Pothos is easy to propagate into dozens of cuttings in one tank.

A few snapshots of one overstocked tank. Note the algae on the rocks.



The gentleman who has this fishroom is happy with this algae. It’s not surprising given the hundreds of grow out juveniles . I am sure this tank is currently getting multiple water changes each week.


I am not suggesting you start adding an algae control medication forever to your tank but it is an option to help as a temporary short term fix.


. This pond algae control is cheap and highly concentrated compared to whats sold for aquariums. Active ingredient Diuron

 

I'd add more of whatever is already growing well. Pick a couple favorites and double down on those. You already have a good selection, and you don't need a huge variety for it to look good. Too much variety can actually make a tank look a bit strange.

True floating plants are also a good choice if you can get them. Things like amazon frogbit, or water spangles.

 

All good advice above. I have lids on all my tanks so adding pothos cuttings aren’t an option for me , I’ve found water lettuce to be an excellent nitrate absorber. Most floating plants are.

Diatoms are very normal in a new set up , faster growing plants and less lights / nutrients also will help. You’ve had a bit of a deep dive into why above ..

 

Thanks all for the very helpful insights and ideas - will shift to RO water with small changes (so that fishes don't get a nitrate shock). 50% weekly change to compensate for the higher stocking. Then will add more plants - the ones that are growing well/ faster growing, including additional pothos.

The best part, as I understand, this algae is not harmful to fish so I won't be losing any, which was the biggest fear I had.

Thanks again to all for the helpful suggestions.

 

This is a long thread but since your water has nitrates I would look for a micronutrient only fertilizer then wait and see if your plants look like they need any P or K. Those can both be dosed separately if needed.

And you need more plants. Get a few stems of a stem plant and start forest somewhere. Once it starts growing chop it down leaving a stump, replant the top, repeat. You need to use up all the free fertilizer in the water.

If you are going with RO get a GH/KH test kit. Figure out what you are dealing with so you don't dilute out all you buffer and have a PH crash.

 

will shift to RO water with small changes (so that fishes don't get a nitrate shock)

Very correct, to switch to RO you can do 4x 25% changes in a row over the course of a week every 48 hours.

Please keep in mind that Platies are among the livebearers that can't stand soft water and low pH well. Get a TDS/EC (total dissolved solids/electric conductivity) meter to check the RO regularly before adding to the tank.

If you want to keep the Platies, pretreat the RO before adding to the tank with minerals that raise GH and KH to reach about 7-10°GH and 5°KH.

If you choose to rehome the Platies you can go 100% RO, pretreated with 3-4 IALs and the fish will be happy.

In both cases after switching to RO you will need a full spectrum fertilizer (macro & micro nutrients), as RO contains no nutrients at all.

 

Very correct, to switch to RO you can do 4x 25% changes in a row over the course of a week every 48 hours.

Please keep in mind that Platies are among the livebearers that can't stand soft water and low pH well. Get a TDS/EC (total dissolved solids/electric conductivity) meter to check the RO regularly before adding to the tank.

If you want to keep the Platies, pretreat the RO before adding to the tank with minerals that raise GH and KH to reach about 7-10°GH and 5°KH.

If you choose to rehome the Platies you can go 100% RO, pretreated with 3-4 IALs and the fish will be happy.

In both cases after switching to RO you will need a full spectrum fertilizer (macro & micro nutrients), as RO contains no nutrients at all.

The bottled water (bottled mineral/ RO water) here has TDS of 20 or around, which I understand is very low. I am planning to use the drinking water RO I have in my kitchen. It has a remineralizer (adds back minerals after the RO stage) and hence TDS is around 80-90. I was hoping this will be enough, but will use fertilizers then.

Thanks again.

This is a long thread but since your water has nitrates I would look for a micronutrient only fertilizer then wait and see if your plants look like they need any P or K. Those can both be dosed separately if needed.

And you need more plants. Get a few stems of a stem plant and start forest somewhere. Once it starts growing chop it down leaving a stump, replant the top, repeat. You need to use up all the free fertilizer in the water.

If you are going with RO get a GH/KH test kit. Figure out what you are dealing with so you don't dilute out all you buffer and have a PH crash.

Sure will keep in mind. Will get more stem plants, which I believe are fast growing as well.

 

I am planning to use the drinking water RO I have in my kitchen. It has a remineralizer (adds back minerals after the RO stage) and hence TDS is around 80-90.

Can you bypass the remineralizer? These things are designed for human consumption, not aquarium water. A TDS reading of 20 is typical for homemade RO, with the 20 being residual ions, I myself would replace the membrane once it surpasses 10, but I'm a softwater freak.
The reminieralizer though adds minerals of unknown composition. At least test it for GH and KH, presumably it will only contain calcium, magnesium and sodium. The latter you will not want in your tank in too high concentrations.

If you are going with RO get a GH/KH test kit. Figure out what you are dealing with so you don't dilute out all you buffer and have a PH crash.

A pH-crash is unlikely as long as the Nitrates stay under 100mg/l, even in zero KH water. Somewhere the H+ has to come from.