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Trying a Caradina CRS tank in a slightly different way

hamfist

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Joined
12 Oct 2023
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7
Location
Southampton, UK
I'm setting up a CRS tank, and I knew I needed a buffering substrate but really didn't fancy having to change all the substrate in a year or two.

I like inert small gravel, and the plants I use seem to like it too. I use fertiliser tablets plus Flourish for micronutrients so they do get what they need in my neo tanks.
The plants I tend to use are Myriophyllum mattogrossense, Limnophila Sessiliflora, Bacopa 'Compact', and Anubias nana.

Thus my cunning strategy is to put Active substrate in an air pump-driven corner filter with most of the media and sponge removed to leave plenty of room for a reasonable amount of the active substrate. I'll keep a close eye on water parameters and pull the filter out and replace the substrate when its showing signs of losing its buffering capacity.

Water is the standard RO remineralised with the usual Shrimp King Bee Salt GH+ to a GH of 6, KH of 0 and ph6.2.

I am hoping that I am being a clever so and so, and not an idiot. Time will tell but it seems like a good plan. I'm a few weeks off actually getting the CRS.
Have any of you guys done anything similar ?
 

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I'm setting up a CRS tank, and I knew I needed a buffering substrate but really didn't fancy having to change all the substrate in a year or two.

I like inert small gravel, and the plants I use seem to like it too. I use fertiliser tablets plus Flourish for micronutrients so they do get what they need in my neo tanks.
The plants I tend to use are Myriophyllum mattogrossense, Limnophila Sessiliflora, Bacopa 'Compact', and Anubias nana.

Thus my cunning strategy is to put Active substrate in an air pump-driven corner filter with most of the media and sponge removed to leave plenty of room for a reasonable amount of the active substrate. I'll keep a close eye on water parameters and pull the filter out and replace the substrate when its showing signs of losing its buffering capacity.

Water is the standard RO remineralised with the usual Shrimp King Bee Salt GH+ to a GH of 6, KH of 0 and ph6.2.

I am hoping that I am being a clever so and so, and not an idiot. Time will tell but it seems like a good plan. I'm a few weeks off actually getting the CRS.
Have any of you guys done anything similar ?
cool idea, though the volume of substrate in the filter doesn't look like a lot, so you may/may not find it exhausts buffering capacity quickly perhaps!
 
It's quite a widely used technique, also similar techniques have been used for breeding soft water fish.
Have a look at Shrimps Affair Singapore, there are a few YouTube videos, showing a very similar setup.
As Aqua360 says you'll need to keep an eye on how quickly the buffering capacity drops to avoid swings in water parameters but otherwise should work well.
 
Hi all,
Welcome to UKAPS.
Thus my cunning strategy is to put Active substrate in an air pump-driven corner filter with most of the media and sponge removed to leave plenty of room for a reasonable amount of the active substrate.
That should work.
and I knew I needed a buffering substrate but really didn't fancy having to change all the substrate in a year or two.
Water is the standard RO remineralised with the usual Shrimp King Bee Salt GH+ to a GH of 6, KH of 0 and ph6.2.
If you are using RO you don't actually need a buffering substrate. You can use an inert substrate (silica sand) and just add some dead leaves etc. to provide some tannins etc. Because <"RO is a blank slate"> the only ions it contains are the ones you've added.
What is the substrate buffering, exactly? pH?
The active substrates work by having their <"initial cation exchange site"> filled with a proton (H+) ion <"which they exchange for a cation"> of higher valency in the tank water <"https://www.lenntech.com/Data-sheets/Ion-Exchange-for-Dummies-RH.pdf">.

If they reduce pH and dKH as well as dGH? They have an anion exchange capacity as well and are swapping an anion (something like chloride (Cl-)) for a bicarbonate (HCO3-) ion from solution

If @hamfist you use your hard tap water <"Some handy facts about water"> that cation will usually be a calcium (Ca++) ion, but at the moment the only Ca++ ions you have are the ones you've already added in your <"Shrimp King"> remineraliser.

cheers Darrel
 
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Thus my cunning strategy is to put Active substrate in an air pump-driven corner filter with most of the media and sponge removed to leave plenty of room for a reasonable amount of the active substrate. I'll keep a close eye on water parameters and pull the filter out and replace the substrate when its showing signs of losing its buffering capacity.

Expensive way of doing it. Chuck in 2-3 alder cones each week and you'll achieve a similar effect, plus the shrimp love to grave on them to boot.
 
Expensive way of doing it. Chuck in 2-3 alder cones each week and you'll achieve a similar effect, plus the shrimp love to grave on them to boot.
I didn't know about this, have you had success with doing this in CRS tanks with exhausted substrate?
 
I didn't know about this, have you had success with doing this in CRS tanks with exhausted substrate?

I've not specifically kept CRS, but I've always found botanicals a good addition for other Caridina and Neocaridina. They all release beneficial tannic, humic, and fluvic acids, which is exactly what the peat is doing in the active substrate the OP is using.

In addition they act as a food source for the shrimp, either directly (in the case of Alder cones, Catappa leaves etc) or as a good base for growing biofilm.

Alder cones can generally be had for free and are readily available to collect, and will generally release a decent amount of the acids which I think is the effect the OP is looking for to buffer down the pH. Though as Darrel points out, pH adjustment should not really be necessary in a zero KH tank.
 
Hi all,
have you had success with doing this in CRS tanks with exhausted substrate?
That could be a slight disadvantage to using an "active" substrate. It isn't really exhausted, it is just at equilibrium with the tank water and therefore will have lost its softening effect. Because <"it is ion exchange"> an exhausted substrate would then actually harden softer water if you added that to the tank.
...... The first time I used the moler clay "Tesco Cat Litter" I rinsed it in our tap water (hard about 18dGH/dKH). It didn't get rid of the smell, and it meant that all the exchange sites were filled with Ca++ and HCO3- ions, so it raised the pH (alkalinity) and hardness of the <"rain-water tanks I used it in">.

If I'd used it in a tank with our hard tap water, it wouldn't have had any additional effect effect, because the ion exchange sites would already have been in equilibrium with the water.

The next time I prepared cat litter I just left it outside in the rain for ~ six months......
With RO and an inert substrate the dGH is all in the water, there isn't a buffer (reservoir) within the substrate.

In some ways that is why I like <"plenty of oxygen">, <"venturi">, <"seasoned tank time">, <"conductivity measurement">, the <"duckweed index">, <"water column dosing"> (rather than <"root tabs etc">) and a <"sand substrate">, basically all the cards are on the table.

All tanks are going to be a <"continually changing dynamic equilibrium">, but you can limit the extent of those changes (retain <"stability">) to stay in the <"Goldilocks zone">.

cheers Darrel
 
In my experience using an active substrate to breed CRS massively helped.

I first started with RO and inert sand and lots of botanicals, and I didn't get any breeding, not even saddled shrimps. Once I switched to aquarium soil, I had hundreds of shrimp. But it's not to say it can't be done without.

Just my two cents!

Edit: Changed berried to saddled
 
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I'm curious as to what is expected (and observed) from the use of active soils for shrimps, especially since most people seem to use RO water and add their own salts, so why would they want the substrate to absorb what they are adding themselves? Couldn't they just add less of that?

Unless it is something that the substrate releases, not what it absorbs. Or maybe it has to do with stability, actual buffering of something. But what? And why would it be fluctuating in the first place?
 
Hi all,

Interesting, that would strongly suggest that the aquasoil adds something else, as well as softening the water.

cheers Darrel

Perhaps a larger surface area for biofilm growth. I've seen shrimp pick up individual grains of soil and rotate them around cleaning them off, which they don't seem to do with sand grains so much. Or perhaps the greater release of fluvic and humic compounds from fresh soil triggers a greater breeding response, and helps improve egg and young viability.

It could also be the much darker colouration of typical soils provides more confidence to shed the carapace - necessary for the females to breed. Though I've no idea how much control the shrimp have over that - i.e. whether increased stress slows the process.

It could also just be coincidence, most shrimp are sold as juveniles, and it can take some months before they are able to breed. In @Courtneybst's case I don't know how old the shrimp were when he got them, and how long they were in the tank before the switch to soil?

That said I've had my tangerine tigers (also a Caridina species) breed on both soil and sand - though for a dedicated shrimp tank I'd probably go for soil in preference.
 
Hi all,
Perhaps a larger surface area for biofilm growth. I've seen shrimp pick up individual grains of soil and rotate them around cleaning them off, which they don't seem to do with sand grains so much.
Sound plausible. In which case @hamfist might get less effect with his soil grains not actually forming the substrate.
It could also be the much darker colouration of typical soils provides more confidence to shed the carapace - necessary for the females to breed. Though I've no idea how much control the shrimp have over that - i.e. whether increased stress slows the process.
Colour might be important. I don't ever have much sand visible in my tanks, so its colour is less important, but I could see a big expanse of shiny, white sand may not be ideal.
Or perhaps the greater release of fluvic and humic compounds from fresh soil triggers a greater breeding response, and helps improve egg and young viability.
We sort have a test for that, if the active substrate isn't the actual substrate, so you would still get the compounds, but not the grains for the shrimps to pick over.

cheers Darrel
 
Thanks for everyone's replies. Some great things to think about and it does seem to me like I have a viable strategy, so long as I keep a close eye on tank parameters (which I would do anyway) and change the active soil at the first sign of any deviation from the norms. I understand this may even be as frequently as monthly, but it will not be a burden to me as the filter is so easy to get to.
I have 2 x pieces of bogwood in there already so will have some tannins from them which, like others, I do believe to be helpful.

As always though, going through this waiting time while the tank matures is agony.
 
Hi all,
and it does seem to me like I have a viable strategy,
I'm definitely leaning towards it being successful.
so long as I keep a close eye on tank parameters (which I would do anyway) and change the active soil at the first sign of any deviation from the norms.
Personally I would <"buy a conductivity meter"> (if you don't have one?) and use that reading as your prime metric. You need to <"find a datum value (range)"> initially, and you choose this by looking at shrimp and plant health, and then just <"adjust the amount of water you change"> (and/or re-mineralising salts that you add) to keep inside that range. It is nice and easy <"and it works">.

I'd <"still measure pH">, but I'd be slightly less interested in that reading than I would be in the conductivity reading. Plants are a complicating factor, with photosynthesis depleting CO2 and <"leading to an increase in pH">.
I have 2 x pieces of bogwood in there already so will have some tannins from them which, like others, I do believe to be helpful.
I'd still use some <"structural leaf litter">, but I have it in all the tanks. Have a look at Rosie's (@shangman)<"Ripe for Picking: a Guide to Collecting your own Bountiful Botanicals">, where this picture is taken from.

image-1-jpeg.jpg


cheers Darrel
 
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Nice, thanks Darrel. I am definately considering some leaf litter as well. I have a huge bag of nice oak leaves I can use, which are pretty much completely cleared of critters, and are now dry.
 
Six weeks later, all is going well with the tank. Water parameters have been rock solid, with no signs of the "active substrate box" buffering being used up yet. I'll report back how long it lasts before needing to be replenished.

Interestingly (on another note), I tried some nicely mature, and partially decayed, oak leaves in the tank for a few weeks. Not once did I see a shrimp on them. Truly, not once. So a few days ago I replaced with Indian almond leaves and within 2 days the CRS are very interested in them and grazing on them. I'm glad I switched.
I've seen a couple of babies in there already and have a couple of berried females so I'm hoping for a population explosion soon.
 
Hi all,
I tried some nicely mature, and partially decayed, oak leaves in the tank for a few weeks. Not once did I see a shrimp on them. So a few days ago I replaced with Indian almond leaves and within 2 days the CRS are very interested in them and grazing on them.
I think that is just because they were Oak (Quercus spp.) leaves. These are very resistant to both grazing and decomposition, because they contain a lot of tannins, terpenes etc.

So very good for tinting the water, but not so good as shrimp food.

In studies of <"leaf decomposition in UK streams"> they use Alder (Alnus glutinosa) leaf discs.
<"Macroinvertebrate identity mediates the effects of litter quality and microbial conditioning on leaf litter recycling in temperate streams">
....... Here, we assessed the contributions of 11 species of freshwater macroinvertebrates to litter decomposition, by measuring consumption rate, fine particle organic matter (FPOM) production, and assimilation rate of highly decomposable (Alnus glutinosa) or poorly decomposable (Quercus robur) leaf litter types. In general, an increase in the quality of litter improved the litter consumption rate, and fungal conditioning of the leaf litter increased both the litter consumption rate and FPOM production. Macroinvertebrates specializing in leaf litter consumption also appeared to be the most sensitive to shifts in litter quality and the conditioning process. Contrary to expectations, the conditioning process did not increase the assimilation of low‐quality litter.

cheers Darrel
 
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