How to Fix Nutrient Deficiencies in Your Planted Aquarium

When it comes to balancing a planted aquarium, we have 3 main components we can change to grow the healthiest plants – lighting, CO2, and plant nutrients. Let's dive into plant nutrients in this video – how I figured out which nutrients my plants were missing, the nutrient test kits I used, and what my fertilization schedule looks like today.

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#girltalksfish #plantedtank #plantedaquarium

0:00 Understanding aquarium plant nutrients
1:07 Estimative Index (EI) dosing fertilization method
1:41 Lean dosing fertilization method
2:20 Plant nutrient chart
3:05 Case study: Back-to-Basics planted tank
3:33 Chapter 1 - algae growth
4:29 Chapter 2 - large holes in leaves
5:55 Chapter 3 - more holes in leaves
6:58 Chapter 4 - curled leaf tips
8:01 Chapter 5 - balanced tank
8:31 Chapter 6 - high bioload
9:34 Which plant nutrient tests do you actually need?
10:35 My current aquarium fertilization schedule

[GirlTalksFish]

*How do you figure out how much and what kind of fertilizers to use when balancing a planted aquarium?*

[johnmarkzimm]

Ok, I finally get it!!!! I understand the barrel analogy… that the plants were missing the lowest nutrient. BUT, when you said you added potassium and the nitrates went down, it finally made sense. It’s like the plants were on hold, until they had everything they needed and were not missing anything. Thank you.

[noelbrucker]

You absolutely read my mind… I was fed up this morning with my constant BBA struggle (almost no other algae) in all my moderately planted, 20 ppm nitrate, 6-8h light-limited tanks, and I was just about to reopen your Balanced Tank video to watch for the dozenth time, when this popped up. Thanks for reminding me to consider any “rate limiting” micronutrients that might be contributing to my issues.

[cloudivaporz]

General rules. Planted tanks with a decent bio-load make plenty of nitrates all on its own and all that fish fish food covers the plants phosphate needs for most plants. Just keep an eye out for deficiencies with testing. Potassium and micro nutrient dosing is usually all that is needed in the water column. I'm not a fan of All-in-One liquid ferts at all. Rooted plants definitely benefit from a nutrient rich substrate where they get most of their nutrient needs from. The substrate or the plant tabs you use should have iron in it as well. Dosing the water column with too much iron can lead to algae problems, especially hair/filamentous algae. The most important tip for whatever type of plants you have is "Feed the roots". Remember, any source of soft water needs to be remineralized.

[SequoiaElisabeth]

Great advice. One thing to remember though is a water change is about not only removing excess, but it also adds in minerals, so this is why I always do water changes, even it is only monthly. My schedule runs 7-10days on the water changes.

[sovrappensiero]

One tip: Seachem Equilibrium contains mostly potassium, plus calcium and magnesium. I use just this + Easy Green + root tabs/aquasoil in all my tanks. You can totally bypass the expensive single-nutrient ferts like Seachem Potassium, etc. Just use Easy Green for trace elements and Seachem Equilibrium for as needed for extra K, Ca, and Mg.

[anotheraccount]

I’m extremely lucky as I am starting my own planted aquarium and you have helped so much, this video is right on time.

[Evil_Genius_]

I started down this fert rabbit hole and just couldn’t. It was too much, but I did learn about my water and what plants were easier to grow in it. I have easy green and extra potassium for the tank that’s almost all Java fern. Plus root tabs for the big root feeders.

[lpaquatics]

Umm...I don't know that I believe that you're a lazy person after this video...you put a lot of work into finding the right balance!! :) Great video...I learned a lot that I'll use!!

[edyoung]

This was a wealth of information!! Thank you so much!!!! Easy to understand!

[ether]

I considered trying the lean dosing route because I have a old tank with high nitrates and my tap water is too high for water changes to keep it below 10. I was going to buy the Flourish but then found LCA had a NP Free version which has high potassium and zero Nitrates and Phosphates so that it's safe to have more fish. All going well the high iron substrate and some nutrient balls for the root feeders should keep things stable for quite a while. - fingers crossed! One thing I loved was getting a aquarium light with a dimmer - currently I only run it for a few hours at low strength while the plants are small so that I can ramp it up in future.

[qpqp]

I really love your tank with those orangey-red platys, they're SO striking against all that green!!

[JAKEY-]

Best EASY straight forward video I’ve seen! I keep coming back to this video!

[takster]

Thank you so much. I have a bit high nitrate and ph. My easy plant do grow, but the rest not so much good. So I will try the potassium and your schedule at once. 👍👍👍

[dusk]

Very good video.
The reason you found such varying advice for recommended nutrients, is thee fold:
1. Very few horticultural trials have been conducted on aquatic plants. If this were an agronomic crop like corn, or a significant floriculture crop like a rose or poinsettia. Then, I could tell you how much the plant needs based off it's growth stage and weight. These are not those plants...
2. It varies wildly by species. An Anubias nana has a different nutrient requirement than a Cryptocoryne wendtii; they need the same number of elements, but the concentrations vary. So unless your keeping a species only planted tank, as in one plant species only; you will only have general guidelines. It also vary according to life cycle, adding to variance. A flowering plant needs a different ration of certain elements vice a juvenile plant of the same species just starting to establish it's roots and shoots.
3. Liebig's law of the minimum has been a corner stone of horticulture and agronomy for the better part of 200 years. It's fantastic to see planted tank enthusiast's starting to understand and use it. However, understanding it shows the third reason: what is your most limiting rate nutrient?
You eluded to it yourself, the limiting rate in a "low tech" tank is likely Carbon. While the limiting rate in a "high tech" tank is likely nitrogen, potassium, or on rare occasions a micro nutrient (sometimes effected by pH). Different environments influence plants to uptake nutrients at different rates, throwing even more variance into reason #2.

But really, speaking as a trained horticulturalist and conservationist: Your videos on this topic were never bad, but you've certainly taken the time to dive into this topic and improve. The information your putting out is great. I specifically like how you contrasted estimated index and lean dosing, certainly hobby specific terms, but important distinctions. Great video.

The only tip I would add is that: you need to remember that the food is a fertilizer. Especially with two macro nutrients. Nitrogen and Phosphorous are readily available in a wide number of tanks, simply from feeding. Either it is metabolized by the fish and excreted, it is broken down inverts, or it's acted on by micro organisms (or any combination). N & P will enter your water column simply from fish food. I'm a large advocate for lean dosing myself, and love all-in-ones due to there ease of use; but, using an all-in-one with N & P (like Easy Green) OR using an all-in-one without N & P (like Florin Multi) comes down to how many fish, how much you feed, and what your plants uptake. I err on the side of an all-in-one without N & P until the plant deficiencies show a lack of either N or P. If you do the opposite, and go with a N & P laced all-in-one: you're likely to create eutrophic water conditions and increase your level of required maintenance (unless you have an equally sufficient plant demand, ya balance... It never ends).

[alexherrera]

Great video, YES you needed all those kits, you would not guess what was the problem without them. I am in the same bote, my GH is 25ppm i know that i need that but i do not know how much Ca or Mg i need to add.

[michaelfox]

Thanks for posting this, Irene. I knew about the rate-limiting paradigm, but had never applied it to planted aquaria. In my case, nitrates have always been low (never more than 5 ppm). I originally had issues with BBA, but cutting down the light has reduced this to a manageable level. What I'm now having trouble with, is extensive black spots on some of my plants (black spot algae?) in another aquarium with relatively low pH (~6.5). This is my betta tank (plus cardinal tetras and Endlers), kept at 25C (78F). The plants with the problems include crypts, java ferns and Rotala, but only some of the leaves get it and it doesn't seem to always be those that are tallest. I'm already down to 6 hours of artificial light, so I don't think light reduction is my answer. I'm thinking of cutting off all of the affected leaves and seeing what happens then.

[blackriverbailey]

Thank you so much for this video! When I first got my two 5 gallons about 4yrs ago, I binged watched all of your videos. I had two bettas in vases and then found out it wasn’t good for them, so I bought the two five gallons and slowly began adding plants. As of right now, I’m suddenly having issues with my plants turning yellow, slow growth, and melting of my floating plants. This has never happened before. All plants live in the water column. Because my tanks are so small, I don’t really think I can add nitrogen or phosphorus. I contacted Seachem and they said the nitrogen isn’t really made to dose that small. I use Flourish, flourish excel, Flourish advance, and the seachem trace, potassium, and iron. I just went ahead and ordered the fertilizer that you suggested, to see if it makes any difference. I’ve seen several videos and forums where people say that Flourish isn’t the greatest. So, I’ll put it on hold while I try out the one that you suggested. Fingers crossed and thank you for all of your informative videos! They have helped me SO much!

[jigokutsuushin]

Cute powder blue gourami! I have a flame gourami with my corydoras and it's adorable.

On topic, I do estimative index on my tank and so far, so good. The plants are relatively algae free but I do get some spot algae on the glass but my bristlenose pleco can keep it check. I do two water changes weekly, each at 20-25%.

[guynum]

Also how likely are you to need the other trace elements like iron and mag