High Nitites and fatalities

[DK123]

Came home from work today to find most of my fish dead   Really upset
Tested the waster Temp 26c Ph 7.6, Ammonia 0, Nitrites 0.25ppm. Nitrates 5.0ppm.
I did a 25% water change yesterday and filter maintenance (Fluval 460)washed the filter sponge with tank water did not replace any media only the fleece on the top.  My other filter Eheim professional I did not touch. I also gently cleaned the substrate Did not feed the fish I only feed the every other day.
Before this the fish have been really healthy,
I use RO water any thing I should do
 
Thanks  Doreen

[TropicalFishForums]

[wijnands]

A .25 nitrite reading doesn't kill an entire tank in a few hours.

There's really little information here to say anything except sorry for your loss.

If you want input then please share
tank size
inhabitants
what do you use to remineralize the RO
What survived
anything that happened at all in the last 72 hours with that tank
also, is this in a room where you use any aerosols or air freshners?

[DK123]

Thank you for your reply, I think I may know what killed them it could have been an overdose of Excel Flourish.  I had a case of BBA and was desperate in getting rid of it.  Advised to increase x4 the dose of  Flourish Excel.  It was 12 hours after that that the fish died.  I have learnt my lesson Flourish Excel states do not overdose and I ignored that to my expense. 
 

[plankton]

Where were you advised to overdose the Excel?
Overdosing Easycarbo or using hydrogen peroxide would be ok for algae, but I've not heard of overdosing on fertlisers, certainly not ones from an off-the-shelf bottle.

[JumpMaster]

I am going to be a a bit rude, but it would be more accurate to say at your fish's expense.

I am quite interested to know who gave this advise.  In future cases, I'd recommend that you post a question here. You will most certainly receive a prompt and accurate reply.

Sent from my SM-G7105 using Tapatalk

[plankton]

I forgot to type...
Sorry for your losses

[ajm83]

Where were you advised to overdose the Excel?
Overdosing Easycarbo or using hydrogen peroxide would be ok for algae, but I've not heard of overdosing on fertlisers, certainly not ones from an off-the-shelf bottle.

Flourish Excel is Seachem's version of EasyCarbo (guteraldehyde? or however you spell that).

Surprised at the 4x dose you were recommended OP, 2x is all I recall seeing.

[plankton]

Is it? How different is it?

[GlassWalker]

Believe there might be a small difference in strength between the products, but even if so, it was minor. I've also heard about overdosing to remove algae, and I have until recently been using 3x strength in one tank in the hopes of shifting some clado. No effect on fish or snails, nor the clado unfortunately. Note I'm using 3x standard dose for medium planting, and heavy planting was double standard anyway. Or, I'm using 1.5x heavy planting dose.

Also the advice I got was to gradually increase it, not just go to high overdose. You can see if things get uncomfortable with the dose and back off before they die.

[wijnands]

Is it? How different is it?

Not. Dillution is all.

This stuff in very high dosage can cause respitory issues when it starts to break down into co2 and the rest. Some stock will react differently, depends on temp, plants, filter outflow and stocking level.

In my opinion yet another reason not to panic when you see algae, it's natural stuff!

[Lurker]

This stuff in very high dosage can cause respitory issues when it starts to break down into co2 and the rest. Some stock will react differently, depends on temp, plants, filter outflow and stocking level.

Which is precisely why I don't use it in my tanks. I have tried it in the past, and even at the recommended dose I noticed some of my fish displayed unusual behaviour, and generally didn't look in tip-top condition.

In my opinion yet another reason not to panic when you see algae, it's natural stuff!

Might be natural, but it can still be an unsightly nuisance, on top of which it smells horrible. There's no way I would put up with it in my tanks.

[Stephen]

Hi Doreen

Sorry to hear of your losses, it can be quite upsetting.

I have also read all your posts to get a better picture of your tanks, fish stocked, water etc..
Your water has fluctuated from pH 8.0 to 6.8 to 7.6 with the use of RO water.
It is best to keep the pH at a steady level to prevent pH shock.
The use of RO water has also altered the hardness of your tank water.
Again a steady hardness level is needed for the fish's "ogmoregulation" (look it up on Google).
Personally I would only stock fish that are compatible to your water hardness (and pH).

As for advice from your LFS, I would take it with a pinch of salt.
It is far better to get advice from actual fish keepers such as the good members on this great forum.
I feel that we are not fish keepers but keepers of the water which our fish live.

I sincerely hope that my post is useful.
Good luck in sorting out your tanks and the fish.

Stephen

ps I would reduce your tank temperature down from 26 degrees to 24 degrees C.

[wijnands]

In my opinion yet another reason not to panic when you see algae, it's natural stuff!

Might be natural, but it can still be an unsightly nuisance, on top of which it smells horrible. There's no way I would put up with it in my tanks.

Tastes differ. For me algae are an integral part of my planting layout.

[Lurker]

Tastes differ.

Can't argue with that.