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Varying readings of Nitrate and fish dying


sandaz

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Hi, hope you guys will be able to answer some of my questions. I've got a fish dying every 2 days at the moment (for the last 2 weeks) with the last casualty seeming to be my large pictus catfish, have put him in a breeding holder and moved to a smaller tank to keep a good eye on him and see if I can revive him.

I've got a 350litre tank with Fluval 305 filter. I do weekly water changes of ~30%, adding Prime(2.5ml), tonic salt(3 tablespoons) and Flourish Excel(40ml) each time.

My water readings today are:

Temperature = 26.5 degrees

Ammonia = 0.25ppm (up from 0 last weekend)

PH = 7.2

Nitrite = 0 ppm

Nitrate readings vary depending on test kit used. If I use the master kit it reads 80ppm, and if I another test kit I've got it reads 10ppm. Not sure which one to believe, but thinking of it now, the master test kit have read that every time I've used it with another tank I had, thought it was still just cycling as it was new.

The other fish seems to be happily swimming around and feeding, but so was the pictus up until today. I'm kind of wondering where to go from here. I've got some expensive fish in my tank and don't want to keep losing them at this rate. I'm going to do a 50% water change tomorrow to see if it makes a difference.

Some advice would be greatly appreciated!

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I've had for a couple of months now but the tank was fully set up for at least a year before that by the people I bought it off. When we transferred the tank we kept half the tank water, changed the carbon an washed the noodles in tank water.

I've not checked the readings weekly (after the first month) as they were stable with Ammonia = 0, Nitrite = 0 and Nitrate = 0.

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what is your stock ? also why the tonic salt and flourish ?

Had 2 pictus, 2 bristlenoses, 10 neons, 1 dwarf gourami, 6 danios, 1 red tail shark, 6 guppies, 6 rummy noses, 2 mollies and 2 swordtails.

Tonic salt added as the previous owners did and I only carried on as per their instructions.

Flourish because I had BBA, but it's all gone now so have stuck with the amount for maintenance on bottle.

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You could bring some water into a fish shop so they can test/check it for you.

the ammonia readings arent good, and I would dose with 'stability' or similar just to be on the safe side.

I will do that tomorrow. Can't understand the spike in ammonia with the weekly water changes. Not overfeeding (1 x day only and only as much as what's getting demolished) and dead fish removed straight away.

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I will do that tomorrow. Can't understand the spike in ammonia with the weekly water changes. Not overfeeding (1 x day only and only as much as what's getting demolished) and dead fish removed straight away.

The only thing I can think about for the ammonia is that you didnt add enough prime, and the chlorine killed the some of your bio filter, causing the ammonia spike.

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The only thing I can think about for the ammonia is that you didn't add enough prime, and the chlorine killed the some of your bio filter, causing the ammonia spike.

So the water changes will correct this? Should I do changes more than once a week for a while?

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a couple of 50% water changes over the next two days and then 30% twice a week. You will have to add prime or smart start or water conditioner and an artificial bacteria if you do the 50% changes.

Please forgive me for asking this question if you are an experienced fish keeper. Do you clean your filter out each time you water change and if so, what do you rinse it in or under?

With the excel you are dosing at the amount for over a 40% water change, if you are changing less than that you will need to adjust your dosing rates. Excel is a liquid carbon and works like CO2. In a larger than recommended dose it can become toxic to fish.

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a couple of 50% water changes over the next two days and then 30% twice a week. You will have to add prime or smart start or water conditioner and an artificial bacteria if you do the 50% changes.

Please forgive me for asking this question if you are an experienced fish keeper. Do you clean your filter out each time you water change and if so, what do you rinse it in or under?

With the excel you are dosing at the amount for over a 40% water change, if you are changing less than that you will need to adjust your dosing rates. Excel is a liquid carbon and works like CO2. In a larger than recommended dose it can become toxic to fish.

I've had goldfish for 5 years but have only switched to tropical and a much larger tank two months ago. So some inexperience you could say. Certainly don't claim to know it all! :)

Filter is not cleaned out each time as the guy I bought it off said to clean it once every 3 months. Will check that today.

Have done a 50% water change this morning and am taking some water into the shop to be tested.

I'm at the end of a cycle of treating my BBA (which started as soon as I took over the tank) so just starting to taper off the Excel, hence the higher dosage. So have been doing twice weekly changes up until a couple of weeks ago. I can see some sort of connection between the timings here, but I've never lost any fish during the BBA treatment cycle and no fish ever seemed to be gasping for air, not even the ones that's been dying off.

Open to suggestions though.

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If you are not cleaning your filter out all the time then thats good. Sometimes people do clean their filters out under tap water every time they water change, which kills off the good bacteria in the sponges and causes a mini cycle.

I do tend to think the excel may have something to do with the issue although it might not be the main cause.

It is often night time when problems occur which means you may not see it happening. If you have an airpump and airline it would not hurt to add them until things are sorted.

Let us know what the test results from the shop are. :D

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If you are not cleaning your filter out all the time then thats good. Sometimes people do clean their filters out under tap water every time they water change, which kills off the good bacteria in the sponges and causes a mini cycle.

I do tend to think the excel may have something to do with the issue although it might not be the main cause.

It is often night time when problems occur which means you may not see it happening. If you have an airpump and airline it would not hurt to add them until things are sorted.

Let us know what the test results from the shop are. :D

Well fish shop tested the water this morning

Ammonia = 0

Nitrite = 0

Nitrate between 10 and 20

Air pump and airline is always going, got that when I started double dosing with Excel.

So maybe it has been just a coincidence. Will do another 50% change in a couple of days time and see how we go. It's all very strange as I've got fish breeding in between all of this happening...

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I do tend to think the excel may have something to do with the issue although it might not be the main cause.

:D

I agree. A recommended dose excel made my corydoras trilineatus go belly up within minutes of adding it each time. I am very wary now with excel and I never dose the full amount because of that experience, and prefer smaller doses more often.

Often an event that has a negative effect on fish health can take a few weeks to show through organ failure IMO, so if there was an ammonia spike (or whatever) a month ago you might only be seeing effects now. A small ammonia spike (and the following nitrite spike) can be over pretty quickly and may be missed with weekly testing, so its possible that there may not be an active problem now but is the result of something that happened a month ago. However, I would still stick to your current plan of water changes etc. If in doubt, change the water!

I would be changing the water as you plan on doing, definitely cutting back on the excel or changing to a much smaller alternate daily dose rather than on once a week, and using a course of seachem "stability" just to be safe as calculator as mentioned. I use stability every time I start up a tank, even if I am moving a fully cycled filter on to the new tank.

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Try leaving the salt out for a while, the cats might not be able to tolerate it along with the other things going on.

Normally it's not recommended to have salt and catfish together as the ones without scales are affected by it.

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Did a 50% water change, good syphon of gravel and cleared the filter out.

Nitrate reading 4 hours later is 10ppm. A definite 10 as before it was kind of between 10 and 20ppm.

Will do another 50% water change tomorrow again.

The salts had been used the entire time the tank has been up and running (18 months) so doubt that's what made the change, but will give that a break too.

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You might want to check the nitrates of the water out of your tap, as you will be unable to get the tank nitrates lower then that (few exemptions).

Yeah will do that tomorrow. Think it is elevated though as it was previously down to 5ppm

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good syphon of gravel and cleared the filter out.

.

I would definitely be getting some Stability if you haven't already as your filter/tank will probably go through another cycle soon - with large water changing combined with cleaning filter and gravel your good bacteria levels could get knocked out.

Has your filter got good flow?

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Just a quick update.

Nitrate down to between 5 and 10 this morning. Dwarf loaches swimming around again and no further fish deaths.

Will do another 50% water change tonight.

Very interesting that discus seems unaffected by all of this.

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