Seeking advice regarding a mysterious freshwater aquarium problem

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Kipley

Aquarium Advice Newbie
Joined
Jun 13, 2023
Messages
2
We have a 50-gal lightly-planted freshwater tank. It’s been up and running for about 9 months.. We have 26 fish, ranging in size from adult Yoyo Loaches to young Julii Corys. We have driftwood for our two plecos and a couple of phony hollow wood logs for the loaches to chase each other through.

50-gal Aqueon HOB filter and a large sponge filter. Imagitarium aquatic substrate.

We feed a few shredded spirulina and krill flakes, a pinch of sinking pellets, and either a couple of algae wafers, veggie rounds or catfish chips twice a day. Frozen brine shrimp substituted for one meal twice a week.

We do around 30-percent water change every week, syphoning the gravel. Perimeters spot-on.

Here’s our problem: Within a day or two after the weekly water changes a light layer of what looks like dust covers everything. I can rub it off the plants but it just comes back. It covers the top of the sponge filter too. You can see small particles floating in the water before it settles on everything. I should mention that new plants often die soon after we get them so it could be plant detritus.

I don’t know if it’s harmful to our fish but it certainly can’t be good.

Whatever it is, it just keeps cycling after each water change.

Any thoughts on solving our mystery?
 
Hi and welcome to the forum :)

Pictures of the thing that settles on stuff?

How often and how do you clean the filter?

It could be from too much food. Cut the feeding back to once a day and see if it helps.

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What are the tank dimensions (length x width x height)?

Do you have lights on the tank and if so, how long are they on for each day and how many watts do they use?

If plants die in the tank shortly after you get them, they could be garden plants that are rotting when put underwater. If you provide us with photos or scientific names of the plants you have trouble with, we can advise further.

Marsh/ garden plants can stand up by themself when taken out of water. Whereas true aquatic plants will collapse when removed from the water.

Lack of light will also kill plants. Plants need 10-16 hours of light per day and at least 8 hours of darkness to rest. See the next post for more info on aquarium plants.
 
AQUARIUM PLANTS 1.01


TURNING LIGHTS ON AND OFF
Stress from tank lights coming on when the room is dark can be an issue. Fish don't have eyelids and don't tolerate going from complete dark to bright light (or vice versa) instantly.

In the morning open the curtains or turn the room light on at least 30 minutes (or more) before turning the tank light on. This will reduce the stress on the fish and they won't go from a dark tank to a bright tank instantly.

At night turn the room light on and then turn the tank light off. Wait at least 30 minutes (or more) before turning the room light out. This allows the fish to settle down for the night instead of going from a brightly lit tank to complete darkness instantly.

Try to have the lights on at the same time each day. Use a timer if possible.

If the light unit is programmable, have it on a low setting for the first 30-60 minutes and increase the brightness over time. Do the opposite in the evening and gradually reduce the light for the last 30-60 minutes before lights out.

If you don't have live plants in the tank, you only need the light on for a few hours in the evening. You might turn them on at 4 or 5pm and off at 9pm.

If you do have live plants in the tank, you can have the lights on for 8-16 hours a day but the fish and plants need 8 hours of darkness to rest. Most people with live plants in their aquarium will have the lights on for 8-12 hours a day.


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LIGHTING TIMES
Most aquarium plants like a bit of light and if you only have the light on for a couple of hours a day, they struggle. If the light doesn't have a high enough wattage they also struggle. Try having the tank lights on for 10-12 hours a day.

If you get lots of green algae then reduce the light by an hour a day and monitor the algae over the next 2 weeks.
If you don't get any green algae on the glass then increase the lighting period by an hour and monitor it.
If you get a small amount of algae then the lighting time is about right.

Some plants will close their leaves up when they have had sufficient light. Ambulia, Hygrophilas and a few others close their top set of leaves first, then the next set and so on down the stem. When you see this happening, wait an hour after the leaves have closed up against the stem and then turn lights off.

Plant lights should have equal amount of red and blue light and a bit less green light.


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TWO LIGHT UNITS
If you have two light units on the tank, put them on timers and have one come on first, then an hour later the second one can come on. It will be less stressful for the fish.

In the evening, turn the first light off and wait an hour, then have the second light go out.

If the lights have a low, medium and high intensity setting, have them on low in the morning, then increase it to medium after a couple of hours, and then high for the main part of the day. In the evening, reverse this and have the medium setting for a few hours, then low. Then turn the lights off.


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LIST OF PLANTS TO TRY
Some good plants to try include Ambulia, Hygrophila polysperma, H. ruba/ rubra, Elodia (during summer, but don't buy it in winter because it falls apart), Hydrilla, common Amazon sword plant, narrow or twisted/ spiral Vallis, Water Sprite (Ceratopteris thalictroides/ cornuta).

The Water Sprite normally floats on the surface but can also be planted in the substrate. The other plants should be planted in the gravel.

Ambulia, H. polysperma, Elodia/ Hydrilla and Vallis are tall plants that do well along the back. Rotala macranda is a medium/ tallish red plant that usually does well.

H. ruba/ rubra is a medium height plant that looks good on the sides of the tank.

Cryptocorynes are small/ medium plants that are taller than pygmy chain swords but shorter than H. rubra. They also come in a range of colours, mostly different shades of green, brown or purplish red. Crypts are not the easiest plant to grow but can do well if they are healthy to begin with and are not disturbed after planting in the tank.

Most Amazon sword plants can get pretty big and are usually kept in the middle of the tank as a show piece. There is an Ozelot sword plant that has brown spots on green leaves, and a red ruffle sword plant (name may vary depending on where you live) with deep red leaves.

There is a pygmy chain sword plant that is small and does well in the front of the tank.


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GROWING PLANTS IN POTS
We use to grow some plants (usually swords, crypts, Aponogetons and water lilies) in 1 or 2 litre plastic icecream containers. You put an inch of gravel in the bottom of the container, then spread a thin layer of granulated garden fertiliser over the gravel. Put a 1/4inch (6mm) thick layer of red/ orange clay over the fertiliser. Dry the clay first and crush it into a powder. Then cover that with more gravel.

You put the plants in the gravel and as they grow, their roots hit the clay and fertiliser and they take off and go nuts. The clay stops the fertiliser leaching into the water.

You can smear silicon on the outside of the buckets and stick gravel or sand to them so it is less conspicuous. Or you can let algae grow on them and the containers turn green.

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We did plants in pots for a couple of reasons.
1) I was working in an aquaculture facility and we grew and sold live plants to shops. Some of the shops wanted advanced plants in pots so we did that.

2) Plants like sword plants love nutrients and have big root systems so they needed more gravel and big pots. When given ideal conditions these plants would produce lots of runners with new plants on and we got more plants to sell.

3) Most of the tanks only had a thin layer of substrate that was nowhere near thick enough for plants to grow in so having them in pots allowed us to grow plants in tanks with minimal gravel in the tank.


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TRUE AQUATIC VS MARSH/ TERRESTRIAL PLANTS
Lots of plants are sold as aquarium plants and most are marsh plants that do really well when their roots are in water and the rest of the plant is above water. Some marsh plants will do well underwater too.

Hair grass is not a true aquatic plant, neither is Anubias.

Some common marsh plants include Amazon sword plants, Cryptocorynes, Hygrophila sp, Rotala sp, Ludwigia sp, Bacopa sp. These plant do reasonably well underwater.

True aquatic plants include Ambulia, Cabomba, Hornwort, Elodia, Hydrilla and Vallis.

The main difference between marsh plants and true aquatic plants is the stem. True aquatics have a soft flexible stem with air bubbles in it. These bubbles help the plant float and remain buoyant in the water column.

Marsh plants have a rigid stem and these plants can remain standing upright when removed from water. Whereas true aquatic plants will fall over/ collapse when removed from water.


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IRON BASED PLANT FERTILISER
If you add an iron based aquarium plant fertiliser, it will help most aquarium plants do well. An iron based fertiliser is not just iron, it contains other nutrients as well, but the main ingredient is iron. The liquid iron based aquarium plant fertilisers tend to be better than the tablet forms, although you can push the tablets under the roots of plants and that works well.

You use an iron (Fe) test kit to monitor iron levels and keep them at 1mg/l (1ppm).

I used Sera Florena liquid plant fertiliser but there are other brands too.


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CARBON DIOXIDE (CO2)
There is no point adding carbon dioxide (CO2) until you have the lights and nutrients worked out. Even then you don't need CO2 unless the tank is completely full of plants and only has a few small fish in or no fish in it.

There are no natural waterways anywhere around the world that have supplemental CO2 added to them to make aquatic plants grow. People add CO2 to aquariums to help some marsh/ terrestrial plants grow underwater. These plants should not be grown in aquariums and the fact they need to add CO2 (as well as huge amounts of fertiliser and light) just to keep them alive is a clear indication they shouldn't be kept underwater.

In an average aquarium, there is a constant source of carbon dioxide produced all day and night by the fish, and the bacteria in the gravel and filter. More CO2 gets into the aquarium from the air mixing with the water. And plants release small amounts of CO2 when resting. There is no real need to add CO2, either in a gas or liquid form to an aquarium unless it is devoid of fish. There is plenty of CO2 in the water in most aquariums.

Liquid CO2 boosters often contain Glutaraldehyde, which is a disinfectant used to clean and sterilise medical equipment. It is highly toxic to fish and other aquatic organisms and people have wiped out tanks by adding too much of it. These products should not be used for aquariums.

For aquarium plants to use supplemental CO2, they need lots of light and lots of nutrients. Unless they have the light and nutrients, they won't use a lot of CO2, so there's no point adding extra. To check if your plants are getting lots of light, see if any of them produce streams of tiny little bubbles from their leaves. This is called pearling and is the plant photosynthesising and producing tiny bubbles of oxygen. Algae also does this when given bright light and nutrients.


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PLANT SUBSTRATE
Some pet shops sell aquatic plant substrates that are meant to improve plant growth. Most don't do anything except add a lot of ammonia to the water and eventually turn into a brown mud on the bottom. Since the majority of aquatic plants take in the nutrients they need via their leaves, having a plant substrate is not going to help much. There are exceptions to this and laterite (red clay) can sometimes be added to the gravel to increase the iron level for the plants taking in nutrients via their roots. But for most plant tanks, all you need is gravel on the bottom of the tank.

Most aquatic plants need at least 2 inches of substrate to grow in and some need 3-4 inches.


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LIGHTING SUPPLEMENTAL
Basically sunlight is the key to plant growth. They need nutrients as well but the main factor is light. Aquarium plants originated from wild collected specimens that grew in full sun light. The plant farmers usually have them in full sun too. It's only when the plants are at a pet shop or put in the home aquarium that they are put under artificial lighting, which is significantly less bright than the sun light they got outside.

Some plants are grown in a laboratory (tissue cultured plants) but even these have lots more light than the average aquarium. Tissue cultured plants are grown in glass containers on wire racks and have multiple rows of light above each rack of plants. The amount of light the tissue cultured plants get is way more than a normal aquarium light but way less than sun light.

Light is reduced in water too and the deeper the water, the less light penetrates it. In an aquarium that is 18 inches high a normal LED plant light will usually produce enough light to get to the bottom of the tank. But if the tank is 2 or 3 foot high, then you need higher wattage lights to get enough light to the bottom of the tank. In the wild, most freshwater aquatic plants grow in water that is less than 10 feet deep, and usually the water is only 2-4 feet deep. When the water is more than 20 feet deep, the amount of red light getting through the deeper water is reduced and other wavelengths (colour spectrums) of light also get absorbed by deeper water. Blue light tends to penetrate the deepest water.
 
Thanks for your reply Colin. Our tank is 36'x18'x18." The light is on for 9 hours. 15W, full spectrum. I change the filters every 2-3 weeks. Rinsing out the gunk in between. We'll try cutting back on food but worry about our larger fish (loaches, plecos) getting enough to eat. I tried dropping a photo into this message but the file is too big.
 
Hey Kipley. I am certainly no where near as knowledgeable as most guys here. Although, I thought I would suggest what the "dust" might be.
2 options I can think off

Option 1
Possibly a beneficial bacterial bloom.

Sometimes when you do a waterchange, the beneficial bacteria escapes the filter and goes back into the water column. I am not sure if this is something to do with a change in heat or the time the filter material was sat out of water.

Usually the bacteria just get sucked back up and go back to the filter.

When cleaning filter material. Make sure you use tank water and not untreated tap water.

Try to replicate the same heat of the tank when putting fresh water in as I believe a big change in parameters (even if very short term) can cause this.

Instead of cleaning the plants. Have you ever left them to clear up themselves?

Also, when you're only doing a waterchange and not cleaning the filter material, I would suggest to use a syphon to take the water out, so you're not messing about with the filter (even if only turning on/off)

Option 2
The other option that it is detrious from the filter/piping. When I do my filter cleaning (monthly), the filter gets turned off.

This means that water and dirt settles and often sits stagnant in the piping

So when I turn it back on the first few seconds is usually full of muck. What I do is get my Mrs to stand there with a little bucket (sometimes a saucepan[emoji23]) to catch the first burst and then put it down the drains.


On the plants melting. Plants can be very trial and error. Some react differently to different heat, pH, hardness and different substrates.

There's also not a great deal of information about the parameters to keep certain plants in.

I have sand which compacts and stops routes from growing, so it's quite hard work.

I personally find anubias (plants with rhizomes) that you attach to drift wood the easiest to keep as you don't put them into the substrate (although I once bought some from ebay which were useless).

I have recently bought hornwort as that also doesn't need to be the substrate.

I suggest you create a plants only post and state all the information you possibly can on all parameters, substrate, even fish (some fish eat certain plants)

I am sure someone that's got a lot of experience will be able to advise you when they know all the details
 
Thanks for your reply Colin. Our tank is 36'x18'x18." The light is on for 9 hours. 15W, full spectrum. I change the filters every 2-3 weeks. Rinsing out the gunk in between. We'll try cutting back on food but worry about our larger fish (loaches, plecos) getting enough to eat. I tried dropping a photo into this message but the file is too big.

If you replace the old filter media/ materials with new media every 2-3 weeks, you need to stop because you are removing the beneficial filter bacteria that keeps the water clean. Biological filters develop colonies of good bacteria that convert ammonia into nitrite, and nitrite into nitrate. If you replace the filter media, you get rid of these good bacteria and the filter has to start developing them again. It can take 4-6 weeks (sometimes longer) for the filters to develop enough good bacteria to keep the water clean.

Established biological filters should be cleaned about once a month. The filter media should be squeezed out in a bucket of tank water and the media is re-used. The bucket of dirty water gets poured on the lawn. However, do not clean a new filter until it is at least 6 weeks old or you can remove some of the beneficial bacteria and it will take longer for the filter to recover. the only time you clean a new filter (one that is less than 6 weeks old) is if the water flow has significantly reduced.

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Set your camera or phone's camera resolution to a lower setting and try taking some more pictures. The lower resolution will make the images smaller and they should fit.

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Don't worry about the fish starving. Unlike birds and mammals that use most of the food they eat to keep warm, most fishes take their body temperature from the surrounding water. This means any food they eat is used for growth and movement. Subsequently, healthy adult fish can go for weeks or even months without food and not die.
 
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