Shrimp deaths

[Aqua sobriquet]

My 60L Nano used to have hundreds of shrimps in it but just recently there aren’t that many. The Corydoras are doing fine though. I’m not actually that bothered by the shrimps at the moment. The reason being that nearly all of them were their natural pinky brown colour. The original shrimps I bought were colourful but I made the mistake of buying a couple of different colours. It was a bit of a quandary as I couldn’t just cull the less colourful ones. I’m now thinking of letting things take their course and restocking with all one colour.

The question is though why are they dying? I’m guessing a lack of nutrients. I do use mostly rainwater so that could be a factor. It has though taken a very long time for the numbers of shrimp to die off to a noticeable degree. I don’t like hard water due to the calcium deposits and the plants definitely like the present water conditions.
I don’t do testing as such apart from TDS which is currently at around 350. I don’t know why it’s at this level but suspect it’s the large piece of Bogwood. I sometimes put some Seachem Replenish in, but not on a regular basis.
Any thoughts or suggestions please?

 

[dw1305]

Hi all,

I do use mostly rainwater so that could be a factor.

I'd guess the water has got too soft for them. It has rained a lot in the last 18 months, which will have washed all the limestone (calcium carbonate (CaCO3)) dust from both roofs and the atmosphere.

I measured the conductivity of the water from the water butt at home recently (not a million miles from you and all limestone locally) and it was 15 microS, which is the lowest value I've ever recorded. Normally in the winter 30 microS is about the lowest value.

cheers Darrel

 

[dw1305]

Hi all,

I don’t do testing as such apart from TDS which is currently at around 350.

That is quite a lot of salts (ions).

I don’t know why it’s at this level but suspect it’s the large piece of Bogwood.

The bogwood won't make much difference, the TDS meter is measuring conductivity and non-ionic compounds don't add electrical conductivity, although they would add ppm TDS if that was what we were actually measuring.

I sometimes put some Seachem Replenish in, but not on a regular basis.

I'd definitely stop adding <"Seachem - Replenish">.

....... Replenish™ restores General Hardness (GH) using a balanced blend of both “soft” (sodium, potassium) and “hard” (calcium, magnesium) salts. Restoration of mineral content is essential since a complete lack of minerals will result in osmotic stress in those species whose osmoregulation systems are adapted to a mineralized environment. .....

I'm guessing that is your issue for both TDS and shrimps, you are adding the <"world's most expensive sodium (Na+) ions and chloride (Cl-) ions">, but not any carbonate hardness (dKH).

I'd stop adding the Replenish and try a bit of <"Oyster Shell Chick Grit">. You are already adding magnesium (Mg++) and potassium (K+) with your fertiliser, so a small amount of <"shell grit">, or <"tap water">, will add a 1 : 1 ratio of dGH : dKH (Ca++ : 2 HCO3- ions).

I agree with @_Maq_ , commercial remineralizers <"are just a rip-off">.

Have a look at <"James' Planted Tank - Re-mineralising RO Water">

You can buy potassium bicarbonate (KHCO3), calcium chloride (CaCl2.2H2O) and magnesium sulphate (MgSO4.7H20) cheaply from ebay (they all have <"food / health usages">).

cheers Darrel

 

[Aqua sobriquet]

Thanks for that Darrel. I’m still on the original small bottle of Replenish I bought over 5 years ago. I didn’t use it very often but perhaps the last dose I put in a few weeks back has caused the problem. I’m going to leave things as they are for a while but I’ll try adding some tap water with the next water change.

 

[Aqua sobriquet]

I’ve had a look at the link Darrel.

James' Planted Tank - Re-mineralising RO Water

I’ve got some gram scales I use with Fertiliser salts so I could get those listed in the link. I’m not sure exactly how I’d use the resultant 25K solution though.

 

[ElleDee]

Are you actually seeing lots of bodies all of a sudden or is it that they just haven't been reproducing enough and the population is decreasing as a result? That would still be a problem, but not exactly the same as a die off event. I agree that lack of mineral content could be the problem either way.

 

[Aqua sobriquet]

Are you actually seeing lots of bodies all of a sudden or is it that they just haven't been reproducing enough and the population is decreasing as a result? That would still be a problem, but not exactly the same as a die off event. I agree that lack of mineral content could be the problem either way.

I’ve not seen any dead ones so I guess they’re just not breeding as freely as they were?