Algae and Nitrates

[Oblio]

I've had several small Pothos to help hold my nitrates down but have moved them to some external vases to dose them with fertilizer to establish the roots after removing them from pots. I noticed that even after a week my nitrates only increased 1 or 2 ppm to about 4 ppm. I have also picked up a fair amount of green algae on substrate.

My question is: Does the algae use nitrate thereby keeping the ppm low?

Note that I don't want to use algae to keep my nitrates low, I'm just seeking to understand what is going on.

 

[Sgooosh]

I've had several small Pothos to help hold my nitrates down but have moved them to some external vases to dose them with fertilizer to establish the roots after removing them from pots. I noticed that even after a week my nitrates only increased 1 or 2 ppm to about 4 ppm. I have also picked up a fair amount of green algae on substrate.

My question is: Does the algae use nitrate thereby keeping the ppm low?

Note that I don't want to use algae to keep my nitrates low, I'm just seeking to understand what is going on.

i think green algae is plants and all plants use nitrate to grow

 

[Essjay]

All plants need nitrogen. Terrestrial plants use nitrate but aquatic plants use ammonia to grow. They keep nitrate under control by taking up the ammonia made by the fish before the bacteria have had chance. Since plants turn ammonia into protein, nitrate in the water does not increase.

 

[Sgooosh]

Aquatic plants use ammonia to grow. They keep nitrate under control by taking up the ammonia made by the fish before the bacteria have had chance. Since plants turn ammonia into protein, nitrate in the water does not increase.

ohhh i always thought they use nitrate
that explains why the duckweed apocalypse turned my nitrates close to 0

 

[StandbySetting]

Aquatic plants can use nitrate, but they convert it into ammonium first which uses more energy

 

[AbbeysDad]

Although it's true that aquatic plants typically 'prefer' ammonia or ammonium as their nitrogen source, some plants and algae will use nitrates. As a matter of fact, there are gadgets like the Santa Monica Filtration HOG1 Algae Scrubber designed to reduce nitrates. Now I believe that algae scrubbers first took hold in the Salt Water world, but found it's way to FW. Here's a bunch of YouTubes on Algae Scrubbers.
So algae is a plant and with sufficient light, will remove 'nutrients' (in this case nitrates) from the water...believe it or not.

 

[StevenF]

yes algae can lower nitrate levels but you would need a lot to do that.

if the only source of nitrogen is nitrate then plants will consume the nitrate. However plants and algae need more than nitrogen to grow. Excluding nitrogen and CO2 plants need 13 nutrients to grow. If just one nutrient is missing you will get no growth and plants will not consume nitrogen. Plants must produce new leaves stems and roots to consume ntrogen.

if you removed your plants from the tank because of damage roots it is likely you have a nutrient deficiency that is preventing root growth. If that is the case you might get better plant growth and nitrogen consumption you by dosing a micro fertilizer. to insure iron, manganese, boron, zinc, copper, molybdenum and niclkle are pressent for growth. Then any nitrogen and posphate produced by your fish will be quickly consumed by the plants.

What fertilizer are you using on your plants right now? Som fertilizers are not complete and may not work well.

 

[Oblio]

Thanks @StevenF, I am not dosing the tank with any fertilizer yet. I have a few Kleiner bar swords with root tabs but I assume that few of those nutrients make it to the water column. I am feeding Ultramicro 5-0-1 in the vases, which I had left over from aquaponics herb growing. This is causing significant new root growth compared to tank alone. Ultramicro lists Ca, Co,Fe,Mn,Mo along with Potash as ingredients.

 

[StevenF]

What brand of root tabs are you using and what are the ingredients in them?

 

[Oblio]

What brand of root tabs are you using and what are the ingredients in them?

Seachem - Flourish Tabs

www.seachem.com

 

[StevenF]

I looked at the fertilizer ingredients and the root tabs use sulfate ingredients. The hydroponics fertilizer uses chelated ingredients.

Sulfate ingredients are sensitive to KH. In high KH water the nutrients are converted insoluble oxides which plants cannot use. Chelated ingredients are resistant to KH. So the root tabs will work best in soft water with a very low KH. You didn't state what your GH and KH levels are and I cannot find that in the water quality report

The root tabs use iron gluconate. iron gluconate dissolves well but bacteria quickly consume the gluconate causing to the iron to oxidize again making it unusable to plants. The hydroponics fertilizer uses Iron DTPA. bacteria doesn't consume it. And it is stable up to a PH of 7.5. Above a PH 7.5 some of it oxidizes. Above a PH of 8 all of it oxidizes. Right now Iron DTPA is typically the best choice for aquariums.

your hydroponics fertilizer is probably too strong to safely use in an aquarium. you might want to try this GLA micro fertilizer This would supply enough micros to allow your plants to keep nitrate levels low and be healthier at the same time.

 

[Oblio]

Sulfate ingredients are sensitive to KH. In high KH water the nutrients are converted insoluble oxides which plants cannot use. Chelated ingredients are resistant to KH. So the root tabs will work best in soft water with a very low KH. You didn't state what your GH and KH levels are and I cannot find that in the water quality report

If found 58 PPM (mg/L) or 3 gpg here, but not sure what the units are

Georgia – HydroFLOW USA: Award Winning Water Treatment Devices

www.hydroflow-usa.com

your hydroponics fertilizer is probably too strong to safely use in an aquarium. you might want to try this GLA micro fertilizer This would supply enough micros to allow your plants to keep nitrate levels low and be healthier at the same time.

I should have made it clearer that the hydroponics fertilizer and Pothos are in a separate vase, not the aquarium.

 

[StevenF]

I should have made it clearer that the hydroponics fertilizer and Pothos are in a separate vase, not the aquarium.

You are clear on that. The issue I see is that if you want healthy plants you need to periodically remove them to put them in a container with your hydroponics fertilizer. And then after they have recovered replant them. Removing and replanting can be just as hard on plants.

Preferably you want the plants to stay healthy without the need to removing them. The GLA fertilizer is a good option to doing that without the problems your current root tabs have and and a few others that might alsobe present.

If found 58 PPM (mg/L) or 3 gpg here, but not sure what the units are

Georgia – HydroFLOW USA: Award Winning Water Treatment Devices

www.hydroflow-usa.com

Be careful in using web sites what sell water treatment products. They have a tendancy to exaggerate and providing incorrect data. The best data source is your utility water quality report. Unfortunately you utility doesn't have a very good water report. So in your case you should test your water with a test kit. However with that said I would not be surprised if your actaual water hands is close to 60ppm. But I have been surprise enough to know that the only reliable way to know is to test your water.

 

[Oblio]

Preferably you want the plants to stay healthy without the need to removing them. The GLA fertilizer is a good option to doing that without the problems your current root tabs have and and a few others that might alsobe present.

Thanks, I wanted to research a bit before adding any liquid fertilizers to my tank. I was also hoping that I could spur some root growth after removing the Pothos from the soil.

 

[ChasingFish]

I found this brief article pretty helpful: https://aquariumscience.org/index.php/5-4-safe-nitrate-levels/