TOO MUCH biological filtration?

[Mystikboy]

So here is my problem: my plants just do not grow, and wither all the time. i think it is because of the seachem matrix absorbing all the nutrients

i run two tanks. the small one (40cm) grows plants beautifully. whatever i put inside, grows. the large one, just does not.

here are some specs:
small one (aquarium)
Pro Z LED lights, hangon filter with seachem matrix, no co2, no chiller/fan, ADA soil, BW Lush and Excel daily, bogwood.
flora: monte carlo/ many lotuses/ HM/ christmas moss/ crypts/ hydrocotyle tripartita, frogbits
fauna: 4-5 ottos

large one (riparium - hence water height is only about 18cm)
T5 Aquazonic lights, eheim 2228 with seachem matrix, no co2, no chiller/fan, sudo sand, BW Lush and Excel daily, bogwood.
flora: many anubias. microsorums, crypts, frogbits. the plants that grow on top of the water either grow exceedingly slowly, or die too.
fauna: 8 rummy noses, 3 corys, 2 l183 plecos, and 3-4 malayan shrimps

i have used the frogbits for a comparison. in the large tank, they slowly lose their leaves, roots shorten, and they disappear/die. on the other hand, in the small tank they grow larger than a 50c coin, with long roots that grow deep into the soil. i have tried to transfer the frogbits from the big tank to the small, only to see them slowly shrivel and die.

so my theory is this: that the seachem matrix is the cause.
you see, in my small tank, i only have about 2 handfuls of seachem.
in the large tank, while my tank is only 2 feet, i have about 4.5l of seachem. i thought that biological media is only a problem when you have too Little, not too Much.
500ml of matrix treats 200l of water.
i have 4.5liters treating about 36l of water.

is there a problem here with the media, or do you think there is something else affecting the large tank?
i have been thinking about this for months. i tried using a fan to cool the tank (maybe because it is a riparium, it is too hot?) but the difference in temperatures was only about 1-2 degrees. maybe the flow in the riparium is too strong? but the flow is weak because it is directed out of a duck bill nozzle and against the wall. nothing seems to suggest why there is such a huge discrepancy between the plant growth in the small, compared to the big tank...

all help appreciated! thank you for reading.

[adidasvintage]

I am not an expert but from what I see, filter media only house "good" bacteria" that breaks down Ammonia to Nitrite, then Nitrite to Nitrate. the amount of "good" bacteria housed will depend on the amount of ammonia released. So if your bio load is low, at most some or most of the media is there without those bacteria as there is not enough ammonia or nitrite for it. Filter media does not take in any nutrients that is mend for plant use.

As for the reason, I suspect its due to the ADA soil used in your small tank, when using sand in the bigger tank, normal commercial ferts are of lower concentration and supporting the fast growing frogbit may not be sufficient. Are the rest of the plants also dieing?

[Mystikboy]

Hello thanks for replying! I always thought that too, but after attempting to narrow the reasons, I can't think of anything else...

Yes the anubias and ferns aren't doing well either. Leaves die now and then, and they aren't growing

[Allan Asis]

Have you tried dosing fertilizer such as Seachem Flourish?

Same thing happened to me for a month and for 2 weeks i've thrown in just about all the types of seachem liquid fertilizer types (iron, potassium, nitrogen, flourish) but the decay continued to get worse. Only when I started dosing flourish trace did plants start to make a rebound. So it was basically an imbalance in nutrients that prevent the plants from absorbing the fertilizers that i've been dosing.

[adidasvintage]

Just bare in mind that ADA aquasoil does Magic to a planted tank due to its rich amount of nutrients. Without it, you just need to supplement more liquid ferts. Also, I believe your anubias, ferns, etc slow growing plant should still do OK with BW lush but with frogbit(fast growing plant) it could be taking in more nutrients and causing deficiency to other plants.

[kurty]

sound like my scenario.. but i don't use matrix..
maybe seachem products too potent..

jiayou, wanna learn too

[Allan Asis]

I'm not an expert here but logically speaking, the amount of biological bacteria in your filter will depend on how much bio load/decay you have in your tank. So even if you have a 4.5L worth of seachem matrix in your filter, the amount of actual bacteria living there just matches your tank as it will only populate based on the amount of decay/waste your tank produces. That said, it goes with the logic that there can never be over filtering.

I could be wrong though, as I'm a beginner myself.

[Urban Aquaria]

Beneficial bacteria do not consume or take out nutrients that plants need to grow, they only convert ammonia and nitrites to nitrate (which plants use).

Bio-media (like Seachem Matrix) only serves as surface area for beneficial bacteria to live in and grow, having more bio-media only allows it to house more beneficial bacteria (which allows for greater potential bio-load handling capacity), but it does not mean that more bio-media automatically contains more bacteria, bacteria populations only grow according to how much ammonia and nitrites are available to consume and convert, if there is more, their population increases, if there is less, their population decreases.

Therefore a tank with very low bio-load and waste would actually have very little beneficial bacteria in the bio-media, doesn't matter if you use tons of bio-media, the beneficial bacteria population only lives in the space it needs, the rest of the bio-media can be empty, only when bio-load and waste build up then more bacteria will grow accordingly and populate the rest of the bio-media.

In your case, the reason for the poor plant growth in the larger tank is very obvious... there is simply just nutrient deficiency in that tank.

Your smaller tank has ADA aquasoil, most people underestimate the nutrient content of ADA aquasoil, it contains a crazy amount of nutrients and has very high cation exchange capacity (CEC) which hold in nutrients effectively for plants to use. There are lots of beneficial bacteria inside that soil doing the waste to nutrient conversion work too. The rooted plants get direct access to all the rich nutrients, hence the plant growth in the tank will naturally be much better.

On the otherhand, your larger tank has inert sand base, so you have to consider that there is no nutrient capacity there. When you dose water column fertilizers according to their basic recommendations, its usually based on tanks that already use active nutrient rich substrates and with existing bio-loads.

As with all fertilizers, you have to adjust their dosages according to tank nutrient content and plant types/density, its not a fixed amount. Therefore, without nutrient-rich aquasoil or sufficient bio-load, you'll need to dose alot more water column fertilizers to compensate for the lack of nutrients in the sand-based tank.

Note that frogbits consume incredible amounts of nutrients, so if you use them in a tank with relatively low nutrient content, they will sap up all the available nutrients very quickly and much faster than the other slower growing plants, so much so that it often starves the other plants of nutrients, which is what you are facing now.

When you see frogbits turning yellow, getting holes or melting, its a surefire indicator there is nutrient deficiency in the tank (could be either macro or micro nutrients, or both), since they are always the first to consume the available nutrients.

So your action plan for the large tank is to dose alot more water column fertilizers (gradually increase the dosage in stages and monitor the plant growth) and regularly remove the majority of frogbits to reduce and control their nutrient removal capacity.

Note that you need to dose both macro and micro nutrients as the plants need the complete combination of nutrients to grow properly. Any shortage of specific nutrients will still result in poor overall plant growth.

One more thing, the emersed plants you have in the larger tank, anubias, java fern and cryptocoryne are still slow growing plants, even when emersed. You usually wouldn't see such immediate growth improvements in the short term even with improved nutrient conditions, as they have been starving and will first soak in much-needed nutrients to store in their rhizomes first... and only after that, then they'll start to slowly grow out new healthy leaves.

In addition, these slow growing plants usually take a longer time to adapt to their new environment (and its common to see older leaves naturally melt). You may need to also mist their leaves regularly to help them adjust to the new conditions (i've experienced old leaves drying out in similar emersed setups as the old leaves may be more used to getting regular water spray/misting at the plant farms).

[Mystikboy]

Thanks for the extensive analysis UA. May I just add that I've a hydrocotyle growing in a pocket of Ada powder soil, but it still seems to be having retarded growth; it's growth is exceedingly sparse, and slow, even though it is emersed and has access to the nutrient rich ADA soil.

[Urban Aquaria]

Thanks for the extensive analysis UA. May I just add that I've a hydrocotyle growing in a pocket of Ada powder soil, but it still seems to be having retarded growth; it's growth is exceedingly sparse, and slow, even though it is emersed and has access to the nutrient rich ADA soil.

Is the hydrocotyle in the smaller tank or the larger riparium tank?

[Urban Aquaria]

Just thinking, if assuming the hydrocotyle is in a pocket of ADA aquasoil (riparium cup holder?) in your larger tank, with part of the cup submerged in the water, in theory that plant should have direct access to sufficient nutrients.

Forgot to ask, how long has the larger riparium tank been setup for? Was the hydrocotyle originally in submersed or emersed form? If it was submersed form, then a possible reason for its current slow growth could be due it still undergoing transition to the emersed conditions, once it transitions it should grow fast.

The other possibility could be the pocket of ADA aquasoil is relatively small (there is no photo of it so i'm just guessing here), so its nutrient content could also be comparatively little, and as the aquasoil is in contact with the tank water, it may have already released most of its nutrients into the water column which in turn was all taken up by the other plants (though the overall nutrients is probably still insufficient for the tank due to the small amount of soil).

Anyways, my suggestions are just based on my own experience with sand based tanks, initially i also encountered very slow stunted growth in most of the plants, and the floating plants also melting, even with fertilizer dosing based on the bottle recommendations. I tried different things, change lights, dose more excel, even change the filter, they didn't make any difference... eventually i just increased the dosage of the fertilizers (went up to 4-5x the recommended bottle dosage), then the plants gradually recovered and started flourishing. So end up it was all just nutrient shortage.

[Mystikboy]

Hmm. Ripariam has been operating for close to 2 years. At the onset, plant growth was great. Then i rescaped and this happened...
Hydrocotyle was purchased emersed from c328. One of those bunches outside the shop, in the styrofoam box. Was initially very bushy but the growth became leggier over time.

The pocket contains about half a cup of soil. Granted, it isn't much and what you conjectured could very well be the case.

Ultimately, though, I think that the biggest mystery is how the Ripariam grew plants well at the onset, and deteriorated since. Further, I only used a small eheim 2232 at the start, and upgraded to the existing 2228 midway, admittedly among other changes as well.


As of now, I have 2 small cups of water with a Frogbit in each, that were taken from the small tank about 2 days ago. Both are now placed under the lights of the large tank. As of now, both still retain their long hairy roots and size. It's a mystery... Perhaps more time will reveal the disparity.

[Urban Aquaria]

The tank has been running for almost 2 years? Okay, then it eliminates all those plant transition/adaption factors... i should have asked about that earlier, save me typing all the extra stuff. Haha.

If the plants were growing well initially and then gradually deteriorated over time, then its most likely nutrient deficiency, since the rest of the tank conditions should be very stable by now. Nutrient deficiency is common as tanks progress over time. As the plants grow out they consume more nutrients, so your fertilizer dosing would also have to increase too, otherwise they gradually die back.

[jiajuen900]

Agree with UA. Biological filtration itself is just a substance that has a high surface area to volume ratio and usually will not affect water parameters. I believe most biological filtration media available should be inert (not 100% sure) except for substances such as coral chips that affect pH.

Most likely due nutrient deficiency. The large riparium has an inert substrate so the only sources of nutrients would be trace minerals introduced through water changes, nitrogen produced from decomposing matter and nutrients added with BW Lush.

Although it is claimed that BW Lush can produce both macro and micro nutrients. I don't actually believe that it is an all in one formula. To my understanding, it is not possible to mix all 20+ elements plants need into one bottle. So BW Lush itself may not be enough.

You could consider adding root tablets to the substrate or using other fertilizers in conjunction with BW Lush based on deficiencies observed in your plant growth.

[AQMS]

The tank has been running for almost 2 years? Okay, then it eliminates all those plant transition/adaption factors... i should have asked about that earlier, save me typing all the extra stuff. Haha.

LOL...

Hmm. Ripariam has been operating for close to 2 years.

My guess is the fert is depleting so that why the plant do not turn out well.

[Mystikboy]

Haha thanks anyway, UA. Your advice will definitely help others who face such issues. (:

I don't really see how it is nutrient deficiency, though. If I had soil in my tank, I can understand that the nutrient capacity depleted over time. Yet here I have an inert substrate, and I have been using Lush all this while..

At any rate, I have been adding flourish as well over the last few days.. We shall see if that changes things.

On another note, with regard to the cups of frogbits, the frogbits in the cups still retain their long roots but the frogbits that I added into the large tank, a day earlier, have had their roots shrink and shorten drastically.

[mUAr_cHEe]

The tank has been running for almost 2 years? Okay, then it eliminates all those plant transition/adaption factors... i should have asked about that earlier, save me typing all the extra stuff. Haha.

Good finger exercise, idol. I would not say that your post is for naught. I did benefit from it. I was just wondering what's wrong with my tank and I just realized it now.