HELP water change killed all my fish!!

Main tank test result - pH very low, ammonia approx 1ppm, nitrite 0ppm, nitrate approx 5ppm.

QT test results just for comparison.

The cories look to be in very bad shape this morning unfortunately. Shallow rapid breathing, barely moving. Not sure if I need to make a call about euthanasia. Can't even find the frogs but I know they're in there!

I'd definitely have no issues getting rid of all that sand that had root tabs in. This thing about loads of beneficial bacteria living in sand is not especially true in all my years of reading around and my personal experience.

Corries might still be in recovery. Euthanasia might only need to come in if they can't keep their balance, or swim properly. How is their colour?

Thats what I was thinking, it's just cheap play sand and I could take advantage of them being in the QT tank to do so, it'll be a pain but I can take my time to do it if need be.

AJ356 said:

I'd definitely have no issues getting rid of all that sand that had root tabs in. This thing about loads of beneficial bacteria living in sand is not especially true in all my years of reading around and my personal experience.

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AJ356 said:

Corries might still be in recovery. Euthanasia might only need to come in if they can't keep their balance, or swim properly. How is their colour?

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Balance is fine, colour is normal, just pretty lethargic. I imagine they're probably still pretty stressed. They're also now in a small group (only 4) but not going to worry about that for now, need to get them through this first.

I'm just glad that, as bad as this has been, my betta tank seems okay in comparison now.

Just to update three out of the four cories have died since my last post. The final one looks extremely lethargic and I am considering euthanasia now to stop its suffering.

I’m sorry about all the problems you’re having…

I’ve gotten away from any chemical additives… no fertilizers, no remineralization of my RO water… I’ve just settled on plants that survive on fish waste, and so far none of my fish have shown me, that they need more minerals, from the water… they get a varied diet… only my Cherry shrimp get straight well water… the Armano shrimp seem to be doing fine in the soft water of my African tank… been thriving for over a year, but they don’t breed in the aquarium, and I’ve not noticed any issues with shedding…

I just don’t trust adding any chemicals to my tanks…

Magnum Man said:

I’m sorry about all the problems you’re having…

I’ve gotten away from any chemical additives… no fertilizers, no remineralization of my RO water… I’ve just settled on plants that survive on fish waste, and so far none of my fish have shown me, that they need more minerals, from the water… they get a varied diet… only my Cherry shrimp get straight well water… the Armano shrimp seem to be doing fine in the soft water of my African tank… been thriving for over a year, but they don’t breed in the aquarium, and I’ve not noticed any issues with shedding…

I just don’t trust adding any chemicals to my tanks…

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Thanks. I only moved over to RO originally because I didn't realise I have very hard water when I first got my cories. I also have a betta so will keep using the RO water for his sake as well.

I've spent the morning removing the substrate and cleaning the tank out. I think for now I'll leave the frogs in the QT tank until I decide what to do with the main one.

It's very sobering to know everything you have worked hard to look after can be wiped out so quickly.

Going forwards, you could try mixing plain RO water with your hard tap water to get the hardness you need. That would leave some minerals from your tap water in the mix.

Magnum Man said:

I just don’t trust adding any chemicals to my tanks…

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I assume you mean you don’t add artificial chemicals to the tank, technically water is a chemical. Are rift lake salts unnatural?
I am cautious of artificial chemicals too. I would use mineral salts if necessary but I didn’t think about if the ones sold for aquariums are manufactured …?

Essjay said:

Going forwards, you could try mixing plain RO water with your hard tap water to get the hardness you need. That would leave some minerals from your tap water in the mix.

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I think I will give that a go, and just be much more stringent about my testing. I think I had finally got to a place where I felt confident enough not to need to test all the time as I thought I knew my tank quite well. I know some people don't test but I think for me, especially after this, it will give me a little more confidence.

RO or RO/DI water can be used in multiple ways. It depend on what one needs to counteract or change.

RO (and eepsecially RO/DI) water should contain nothing bad, but it also contains nothing good either, besides the water. Some water is so bad it should not be used at all. In this case one must remineralize the RO. On the other hand, one's water may be too hard and/or have a way too high pH. In such cases one then can use the RO water to adjust the tap water by diluting it.

When you are adjusting your parameters for whatever reason, you need to be more stringent about testing. It is usually easier for "mixed" water to drift from the parameters we set for it than it is for naturally occurring water to change. So we need to monitor more actively. I use a continuous digital monitor on the one tank where I alter my tap paramters.

I also live in an area we may get some insanely heavy rain for an extended period or the exact reverse. This effects the parameters of out well water. Over the year my pH ranges has been 53 ppm to 110+ ppm. It has had a pH of 7.0 - 7.4. It may have slipped to pH 6.8 but I never saw it there but can assume it hit that number when the TDS hit their lowest.

The above is why I need to check my tap params every now and then. But how I know when I should check them I can tell from the reading for the chaging water I batch for the one tank where I change them. I started at 10::10 gal mix RO::Tap. Today I use 11::9. My parameter monitor alerted me to the need to change the ratio.

Essjay said:

Going forwards, you could try mixing plain RO water with your hard tap water to get the hardness you need. That would leave some minerals from your tap water in the mix.

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Yes that is what I do with my RO/DI water. I mix a 60/40 (RO/tap) ratio in the aquarium. I remove the water from my tank and then I add Seachem Prime dosage for the total volume of the tank. I add the amount of tap water to my tank, then I add the RO/DI water to fill the remainder of the tank.

I stopped mixing tap water directly into my RO/DI holding tank in order to prevent the tap water nutrients from causing biofilm buildup in the holding tank. Keeping just RO/DI water in the holding tank eliminates the biofilm buildup issue I was experiencing previously.

Fishfunn said:

Yes that is what I do with my RO/DI water. I mix a 60/40 (RO/tap) ratio in the aquarium. I remove the water from my tank and then I add Seachem Prime dosage for the total volume of the tank. I add the amount of tap water to my tank, then I add the RO/DI water to fill the remainder of the tank.

I stopped mixing tap water directly into my RO/DI holding tank in order to prevent the tap water nutrients from causing biofilm buildup in the holding tank. Keeping just RO/DI water in the holding tank eliminates the biofilm buildup issue I was experiencing previously.

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Potentially a silly question but adding in this way doesn't upset the fish at all?