Amano Shrimp and Die Off

[Biollante]

Hi David,


Bingo as they do say!



Yes, heavy metal contamination is fairly common in non-food grade/agricultural fertilizers. It is why we always check.

Very small doses of some metals are acute toxins.



I really thought there must be some kind of toxicity and particularly metal.



Big, as in 60-70% water changes every other day for a week or 10 days, with continued use of activated charcoal and extra Prime dosing.


Obviously new fertz.

Biollante

[Philosophos]

If you added the K2CO3 dry, the exothermic reaction may have nuked your shrimp. I'm not sure how volatile it is that way, though; never worked with it. Heavy metal poisoning tends to take more than 2 hours to cause death. Either way, suspicion should sit with the K2CO3 first (less tested in the hobby) and the KNO3 second, since it's still from an unknown source.

[nicewicz]

Just to be certain, I pulled out my pH probe from the inline setup on my tank and took accurate pH readings (I just calibrated my probe a few weeks ago as well).

Untreated tap water: pH = 6.5
Aquarium water: pH = 6.3
Water the shrimp arrived in: pH = 5.9
Shrimp test batch 1: pH = 6.2
Shrimp test batch 2: pH = 6.4
Shrimp test batch 3: pH = 6.4

So, nothing funny is going on with wild pH swings or anything.

Yep, I learned my lesson here. I think that trace heavy metal toxins present in the ferts have to be the cause of the problem as well. That would explain why the shrimp (and even fish to some extent) freak out every time I do a big water change and re-add fertilizers.

I will follow your advice and do huge water changes every other day to rid the tank of the contaminates. I wonder if these could also be screwing up my bio-filtration as well...
I will keep everyone posted on how this turns out. Could still experience more shrimp deaths, but hopefully this will slow things down to an eventual halt. Thanks in advance for everyone's help and advice. It was really fun, in a way, to show that carefully designed experiments can provide immediate concrete answers.

Looking forward to seeing my tank full of happy shrimp...

[nicewicz]

If you added the K2CO3 dry, the exothermic reaction may have nuked your shrimp. I'm not sure how volatile it is that way, though; never worked with it. Heavy metal poisoning tends to take more than 2 hours to cause death. Either way, suspicion should sit with the K2CO3 first (less tested in the hobby) and the KNO3 second, since it's still from an unknown source.

Good points, however, I added the smallest amount of K2CO3 and dissolved it completely in tap water (along with the trace amounts of other ferts as well) and let it sit for a few minutes. I did not feel an exotherm, so I don't think it's that. I really am suspicious of all of the chemicals that I've added as they are not food/agricultural grade. It may not even by heavy metals that are to blame here, though they are certainly prime suspect number one.

[nicewicz]

Do you guys just add baking soda for carbonate hardness/pH buffering capacity?

[Philosophos]

Even on pure RO tanks, I don't buffer. My wife spawns betas sometimes; she dumps indian almond leaves in with RO, the pH goes down to 6 or less, and they spawn beautifully. Water isn't going to turn into vinegar on you unless something is added, and it's KH not pH swings that tend to hurt fish.

[nicewicz]

Right, just didn't know if a specific KH was required for certain plants.

Just finished the water change and the remaining shrimp did not do laps around the tank like they normally do after I do a water change and add fertilizers. I'll add the test shrimp to the tank and monitor progress over the next several days/weeks but hopefully we solved the mystery.

[Philosophos]

Well if you've got it narrowed down to ferts, replacing the KNO3 and K2CO3 shouldn't be too hard... unless you're in a highly restrictive country.

Some plants do better in high KH, others in low, it's nothing that usually prevents a plant from growing. Read up on what you have from multiple sources, see if anything has a real requirement for KH.

[Left C]

... After a 50% water change (on a 65 gal aquarium), I add Prime (5 mL) ...

Your dosing of Prime may be a little low. The recommended dose for Prime is 5 mL per 50 gallons or 2 drops per gallon. You should dose Prime based on the full tank volume when you add it as when you do water changes.

According to your water supply report, Durham uses chloramine. You might not be adding enough Prime to neutralize it. I live a few miles away in Burlington, but chlorine is used here.


Prime Dosing Directions: http://www.seachem.com/Products/prod...ges/Prime.html
Use 1 capful (5 mL) for each 200 L (50 gallons) of new water. This removes approximately 1 mg/L ammonia, 4 mg/L chloramine, or 5 mg/L chlorine. For smaller doses, please note each cap thread is approx. 1 mL. May be added to aquarium directly, but better if added to new water first. If adding directly to aquarium, base dose on aquarium volume. Sulfur odor is normal. For exceptionally high chloramine concentrations, a double dose may be used safely. To detoxify nitrite in an emergency, up to 5 times normal dose may be used. If temperature is > 30 °C (86 °F) and chlorine or ammonia levels are low, use a half dose.

[nicewicz]

Good point Left C. I'll bump up the Prime amounts as well.

So far, so good. Two days with no more dead shrimp. All appears to be normal with their habits and they are picking a few pieces of fish food that sank to the bottom of the substrate. I'll do another water change in a day or so, but I'm still convinced that it was the trace impurities in the fertilizers that did it.