Long term decline

[idris]

My 240L tank's been going for several years.
Where I used to have Valis, Crypt Wenditi and Amazon Swords (all pretty healthy), the swords have disappeared, a lot of the Valis has gone and the crypts have pretty much taken over.

I improved the flow a few months ago by adding a power head, and have reduced the hours of light to combat algae which has largely helped. I also added ferts but there wasn't an obvious impact once the algae had gone.

I'm sure I could do with doing water changes more often (I tend to do 20% every fortnight rather than 10% every week).

Other than the plants, the fish are less active (or only last a few months), I rarely see my assassin snails, and the whole tank doesn't seem as vibrant and full of life as it used to.

Any thoughts? Different regime? Replace Adakama?Different plants? More light (and fight the algae a different way)?
(CO2 not an option)

 

[ian_m]

Are you providing a regular carbon source eg liquid carbon as well as regular fertiliser doses ?

 

[idris]

No, but IIRC liquid carbon is bad for Valis.

 

[parotet]

No, but IIRC liquid carbon is bad for Valis.

Yup, but the rest of plants will need it... In my first tank I had Vallisneria nana and adding liquid C at the recommended dose was not a problem for them.
Having a C source is definitely a need in a planted tank... and the more light the more C needed (as well as other inputs).
I would say: less light, liquid C or much better pressurized CO2 (much cheaper in the long term in you 240 liters tank). Adding CO2 does not mean necessarily high tech, my tanks are a medium light but Co2 enriched (= healthy plants, undemanding tank)

Jordi

 

[dw1305]

Hi all,

I'm sure I could do with doing water changes more often (I tend to do 20% every fortnight rather than 10% every week).

I'd just up the water changes for a bit and see if it makes any difference.

cheers Darrel

 

[Jose]

No need to dose liquid carbon if you dont want to. But you need to dose ferts.

 

[alto]

the fish are less active (or only last a few months

This says that something is very much amiss in the tank ... I'd likely strip down the tank, replace substrate, clean out filter etc but just upping the water changes to 10% daily for this week, then 20% daily for the next week - tank water will gradually transition over to matching tap water - then you can just perform weekly 50% water changes for a month or so & assess how tank life is doing ...

I'd not disturb the filter or substrate until you've transitioned the tank (fish) over to tap water - this way if anything untoward happens & fish appear very stressed, large water changes can be used to clear out anything that's appeared in the tank with your activities.
Usually moving to 20% daily water changes is "safe" but if you've been doing perhaps 20% fortnightly & as fish are currently stressed, I'd be more conservative.

I also added ferts but there wasn't an obvious impact once the algae had gone.

Just adding more fertilizers without other changes won't improve things much, it's possible that the substrate has some issue (imbalance or oddity) & I'm impatient & enjoy re-scaping, so I'd strip out the substrate - remove fish & any shrimp safely elsewhere, note that if your assassin snails have died, I'd for sure be stripping out the substrate as they are extremely resilient - though you can leave this as a last step if it's not something you're keen to do.
Just getting the tank onto larger more frequent water changes (that 50% weekly) may re-establish the tank, though I'd still be very cautious of disturbing the substrate to add in new plants.
I expect that both the crypt & val roots are everywhere, I suspect that new plants will not easily establish unless you do the re-scape: vals are certainly very capable of releasing compounds (into both the water column & substrate - depending on my recall accuracy) to "discourage" other plant types.

As you're not adding CO2 nor have you in the past, I expect plants were depending on the low levels that naturally enter into the tank water column from 1) tap, 2) fish respiration, 3) surface gas exchange (re atmospheric CO2),, so just moving to that 50% weekly water change schedule should help revive existing plants, fish activity should improve but don't add in new fish until tank seems back to normal.

When cleaning the filter, it's usually safe to remove all debris in one go, just be sure to use tank water (& treated tap water) to rinse filter media, clean out your hoses before re-starting the filter otherwise you may be astounded at the murk that dumps into the tank (I'm assuming an external filter).

 

[Stu Worrall]

akadama tends to suck all the minerals out of tank water. Just wondering if its the case here or have the crypt roots taken over the substrate and clogged it up? Definately add ferts and change the water more often to see if it makes a difference plus all plants need some sort of carbon whether it from liquid or gas or from the water out the tap

 

[Jose]

akadama tends to suck all the minerals out of tank water.

This is the thing. People are worried about dosing ferts, then the substrate sucks up the little they put in so result is dying plants and dying fish. After this its just recommended to add co2 in one way or the other which will just make everything worse.

 

[dw1305]

Hi all,

akadama tends to suck all the minerals out of tank water.

This is because it has a "cation exchange capacity" and the exchanges sites are initially filled with H+ ions, because the Akadama originates from an area with high rainfall.

But I don't think it is relevant to the OP's post.

When you place the Akadama in the tank water it will exchange the H+ ions for other cations that are more strongly bound. Multivalent ions (like Ca++ and Mg++) are more strongly bound than monovalent ions (like K+), but exchange occurs according to both <"their place on the lyotropic series">, and their relative abundance in solution.

This is also why "active substrates" reduce hardness and pH initially, they are exchanging H+ ions for Ca++ ions etc. Once all the exchange sites have Ca++ ions bound exchange will largely stop, and the substrate won't effect the water parameters.

They only exception to this is if we put the Akadama into a strong ionic solution of another cation. If less strongly bound cations are present in very large numbers exchange will occur swapping the more strongly bound cation for the less strongly bound one.

If the strong solution was NaCl, the sodium ions would replace the calcium ions (like in a domestic water softener), and if it was a strong acid (like HCl) the H+ ions would replace the Ca++ ions, getting us back to where we started.

cheers Darrel

 

[idris]

I was under the impression Adakama was a good thing, a good way to get pollutants out of the water column and into the plants via the roots but had wondered whether it had a "finite" life. Or maybe I've got that wrong.
Considering it's been in there for 3 or 4 years, and we've got very hard water, should I look to change it?

And any thoughts on a possible excess of Crypt roots? Is that possible?

(I don't mean these as an alternative to CO2 and or better water changes, just trying to figure out what's going on.)

 

[dw1305]

Hi all,

I was under the impression Adakama was a good thing, a good way to get pollutants out of the water column and into the plants via the roots but had wondered whether it had a "finite" life. Or maybe I've got that wrong.

I think it is a good thing.

You could think about it a bit like activated charcoal, it won't be "activated" for very long, but once it has stopped being a chemical filter it is still a good biological filter medium.

Cation (and anion) exchange capacity is exactly that "exchange", once the substrate is in equilibrium with the water then few ions will be exchanged. They are still potentially available to the plant, particularly if REDOX values vary in the substrate.

and we've got very hard water, should I look to change it

This will just mean that all the exchange sites in the Akadama are filled with Ca++ ions.

cheers Darrel

 

[idris]

Presumably that means the there are no ions useful to plants are that are available to them through their roots?
Is there a simple to remedy that which wouldn't involve stripping the tank and wouldn't pose a risk to flora or fauna? Or is it even worth it?

 

[dw1305]

Hi all,

Presumably that means the there are no ions useful to plants are that are available to them through their roots?

Not really, it just means that the substrate would behave more like an inert quartz based substrate, and you have a large calcium reserve within the substrate.

Any humic compounds within the substrate will still have CEC, and in areas within the substrate where you have a fluctuating boundary between oxidising and reducing conditions nutrients will become available.

Is there a simple to remedy that which wouldn't involve stripping the tank and wouldn't pose a risk to flora or fauna? Or is it even worth it?

No there isn't really any easy way back, but I don't think you are necessarily in a bad place.

I like mature substrates, there is a good description here: <"Skeptical Aquarist: Substrate">.

I think if you up the water changes, things should return to normal. If you don't feed much magnesium (Mg) you could up the amount a little bit, and possibly try a different chelator for iron(Fe) if you use FeEDTA.

cheers Darrel

 

[idris]

Thanks. I'll have a read of that link later.

In the meantime, the rest meant little to me I'm afraid. (Maybe the link will help.)

Is there any value directly to the plants in having "a large calcium reserve within the substrate"?

Does Adakama have humic compounds? My substrate is 100% Adakama, so no peat or anything like that (which I think is "humic") so I'm guessing not. IIRC a lot of people use peat, but realistically that would mean a lot of work in my tank and be a royal PITA.

I've run out of ferts and hadn't ordered any more as they didn't seem to make much difference once the algae had gone (and light and flow changed at the same time so I have no way to judge which was the most effective). I think I was just using a NPK solution so can recommend something that includes magnesium and iron?

 

[Alexander Belchenko]

Are you talking about the tank you have link in your signature (tall 250l tank)?
I wonder if your decline due to build up of organic waste in your tank. Smaller water changes don't help to remove such waste AFAIK.
There is non-scientific test using by our local planted tank guru based on using water coagulant in small doses to detect how much of organic waste your tank may have.
Overall, you may need to remove as much of possible organic waste built up over those years as practically possible.

As other people suggested you need to increase your water changes to help the water match the tap water.
Also, may I suggest you to inspect how much detrius you have in your acadama. Maybe removing some of such detrius (without being too fanatical about it) will help too. If you will uproot some of your crypts you can reach the substrate with syphon. If you're about to re-design the tank, you can make such cleaning during several weeks.

IMO you just need to soft restart your biosystem. Ensure you have enough oxygen for fish. Are you using extra aeration or only ripples on the surface?
Check how old your lamps, maybe it's time to change it, but not all at one time.

It will be interesting to see current picture of your tank and substrate close-up.

 

[dw1305]

Hi all,

Is there any value directly to the plants in having "a large calcium reserve within the substrate"?

It could interfere with the uptake of some other ions, mainly Mg++, Fe+++ and, to a lesser extent K+.

Does Adakama have humic compounds? My substrate is 100% Adakama, so no peat or anything like that (which I think is "humic") so I'm guessing not.

No, the Akadama doesn't, it is leached volcanically heated clay with only the insoluble iron and aluminium compounds left, but overtime "mulm" will build up in the substrate. This is what Alexander is alluding to here

I wonder if your decline due to build up of organic waste in your tank. Smaller water changes don't help to remove such waste AFAIK. There is non-scientific test using by our local planted tank guru based on using water coagulant in small doses to detect how much of organic waste your tank may have. Overall, you may need to remove as much of possible organic waste built up over those years as practically possible.

Personally I'm not convinced that "mulmy" substrates are a bad thing, I quite like them, and I don't make any effort to remove all the mulm.

I've run out of ferts and hadn't ordered any more as they didn't seem to make much difference once the algae had gone. I think I was just using a NPK solution so can recommend something that includes magnesium and iron?

OK, that makes nutrient deficiency much more likely. The likeliest deficiencies are nitrogen (N) and potassium (K), mainly because plants need about x10 more of them than any other elements.

Because of your very hard water magnesium deficiency is also a possibility (due to the Ca/Mg ratio). Magnesium you can buy very cheaply as "Epsom Salts" (MgSO4.7H2O), after that I'd buy a <"complete nutrient mix"> from one of our sponsors.

cheers Darrel

 

[Alexander Belchenko]

Personally I'm not convinced that "mulmy" substrates are a bad thing, I quite like them, and I don't make any effort to remove all the mulm.

Probably I wasn't very clear in my post. I don't say "mulm" is bad thing, just one of the reason for organic waste. Don't need to remove all, just clean the surface of substrate from extra 'mulm' IMO.

 

[idris]

Thanks all.
I think I've got enough try and keep be busy.
Removing mulm may be a labour, as there is almost no substrate not covered in Crypts (or the little Vallis that's left), but where there's a will ...

Are you talking about the tank you have link in your signature (tall 250l tank)?
...
It will be interesting to see current picture of your tank and substrate close-up.

Yes. That's the one. Will try to get round to posting a pic.

 

[dw1305]

Hi all,

as there is almost no substrate not covered in Crypts

This would probably suggest that there isn't too much fundamentally wrong with the tank conditions.

cheers Darrel