# Nitrate explosion



## lancergtsguy (Aug 15, 2013)

Hi there

A little background... I have had my 125g tank up and running now for the last 5-6 months now. There is about 50 fish in there. I run a fluval fx5 with all 3 trays filled with bio max and Purigen. I also have a fluval 306 set up as it comes out of the box.

I do approximately 20%-30% water changes about once a week. I do the big cleans about every two weeks off setting the canisters every other two weeks so they aren't both being done at the same time so to not be such a dramatic change in the water conditions. This includes dumping out the water from the canister filters a quick wipe of the inside of the canister and rinsing out the filters. From the time the cycle completed and up untill the big clean on November 29 my water peramitors have been perfect. 

After I did the big water change on November 29 which was done on the Fx5 I noticed my fish flashing so I tested the water and I had a nitrate spike. For the rest of that week I did about two 20% water changes trying to keep the nitrates down. Did a 40% water change just two days ago and and my guys are flashing again so testing the water and it looks like I am going to continue doing 20% water changes just to keep down the nitrates. I fear if I continue this way I will completely throw my tank out of wacky if I haven't already. 

I've also slowed down my feedings during this time. 





Any suggestions what could be my problem?

I don't think I have any dead fish in my tank.


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## jobber (May 14, 2010)

By cleaning out the canister filter as thoroughly as you stated, may have killed off beneficial bacteria thus resulting in your tank going through a cycle; allowing the beneficial bacteria colony to re-establish itself relative to what you feed. You should also check to see if you have any dead fish that may have lead to a spike in nitrate.

If in doubt, you should just seed your tank with bottle bacteria or bacteria conditioner after water changes. Check out Seachem Stability.
It's worked for me and it works just as good for you.

SeaChem Stability Water Conditioner - 500ml


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## Rockman (May 19, 2013)

What's the species breakdown in the tank? Do you have any sludge accumulating anywhere? What are your nitrate levels normally and how much have they gone up by?


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## MEDHBSI (Sep 4, 2011)

If you do some large water changes with aged water youll be fine. I've done 100% water changes many many times with no issues to my beneficial bacteria. As long as your fish keep pooping your bacteria won't die on you.


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## Fish rookie (May 21, 2012)

I am sorry a bit off topic. Is flashing a symptom of having too much nitrate?


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## Steve (Mar 27, 2013)

What's your nitrate at? Nitrate isn't affected by beneficial bacteria and can only be reduced by water changes for fresh water takes (aside from some refugiums and other things) so I don't think it has something to do with the way you clean your filters. My guess is that there's something dead in your tank that's giving off a lot of ammonia which is causing it to be changed into nitrite and then into nitrate and accumulating. Search around for dirty areas!


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## Fish rookie (May 21, 2012)

Even if your bio filtration was gone completely, you should have a high ammonia and high nitrite instead of high nitrate. High nitrate is produced by your bio filter converting lots of ammonia into nitrate. At least that is what I think.
I am curious is flashing related to high nitrate? I do not really have much experience in this. Sometimes my fish flashed but then they stopped and I never had one died because of flashing so I never thought much about that. LOL
But how high is your nitrate reading anyway?
Your fish are bigger now may be if you keep the same water change schedule you cannot keep the bio-load to be as low as before so you just need to change a bit more water or do it a bit more frequently to get the same nitrate reading. Without knowing how high is your nitrate it is hard to say.


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## tony1928 (Apr 22, 2010)

Yeah I think Steve's on the right track. If there's a nitrate spike, something is decomposing and with that many fish, often you won't notice if one has died and is hidden away somewhere you can't spot easily.


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## lancergtsguy (Aug 15, 2013)

Hey Jobber. Thx for the insight. I did off set the big cleans with the canister filters to every other 2 weeks to avoid the issue of killing off a huge load of benificial bacteria but i guess i still may have done some damage there. Any suggestions on the best way to clean my canisters so that i don't have this problem in the future?


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## lancergtsguy (Aug 15, 2013)

I have a mixed african cichlid tank with a couple clown loaches in there. As far as sludge goes, nothing i can see visually. Not to say there is nothing hidden same goes with any dead fish. I will have to take the rock work out and see if there is anything hidden. As far as readings go I use the Nutrifin Master Kit and my Nitrate reading starts at 5 normally and by the end of the week hits about 20 on the color chart. I do my regular water change and back down to 5 it goes. Unfortunately now the problem is after i do the water change the nitrates stay high around the 20 mark and I just can't seem to get it back down. All other reading seem to be spot on. I mean i am happy the nitrates are maintaing in the safe zone but still concern about the spike and upset in the balance.


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## lancergtsguy (Aug 15, 2013)

Great thx Steve. Good to know. I will check the rock work and see what is going on. It would suck if it's a dead fish but still hope that a dead fish is all it is. It'd be nice to find the problem.


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## lancergtsguy (Aug 15, 2013)

Fish rookie- I've been told (Anyone can correct me if i'm wrong) that flashing can mean many things. But a good start to check is water condition and has it changed? As a sudden change or spike somewhere can casue the fish to be stressed and flash. If this wasn't the problem then their may be bigger problems arising.

Since I've heard this it's been a great refference for me and has allowed me to be on top of any changes in the tank. Like this prolem at hand.


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## jobber (May 14, 2010)

lancergtsguy said:


> Hey Jobber. Thx for the insight. I did off set the big cleans with the canister filters to every other 2 weeks to avoid the issue of killing off a huge load of benificial bacteria but i guess i still may have done some damage there. Any suggestions on the best way to clean my canisters so that i don't have this problem in the future?


Use tank water to rinse out biomedia. Using tap water that contains chlorine traces can kill off bacteria.


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## lancergtsguy (Aug 15, 2013)

hey jobber great tip. I have 2 buckets filled with tank water every time. One to hold the biomedia and the other to rinse out the filters. The inside of the empty canister is the only thing i have been cleaning with tap water.


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## Fish rookie (May 21, 2012)

If you do a big water change, even if there is a dead fish or something, your nitrate should stay lower than before right after your water change. Your problem is not a lack of nitrifying bacteria in my opinion. Your bacteria also live in your tank on the rock, substrate...not to mention cleaning the filter the way you did should not have wipe them out. The fact that you have a high nitrate reading means your nitrifying bacteria is doing its job. How about your ammonia and nitrite readings, if they are zero your bio filtration is fine. Nitrate reading is not the one to check if your bio-filtration has crushed or not. Just my opinion.
I would check the kit to make sure it is not expired first. 
I usually do my water change before my nitrate hits 10ppm, and after my water change my nitrate is under 5ppm. I do a 50-70% water change. I do not understand how you can have 20ppm before and still 20 ppm after a decent sized water change. If it happens to me I would get a new test kit because I just do not see how my water can have the same amount of nitrate before and after a 50% plus water change--how can one dilute 20ppm by half (i.e. 50% water change) and still gets 20ppm?
But either way, it should not be an issue about whether you have killed off the nitrifying bacteria or not, I think your nitrifying bacteria are fine if I have to make a guess. You can test your ammonia and your nitrite to find out. just my 2 bits.



lancergtsguy said:


> I have a mixed african cichlid tank with a couple clown loaches in there. As far as sludge goes, nothing i can see visually. Not to say there is nothing hidden same goes with any dead fish. I will have to take the rock work out and see if there is anything hidden. As far as readings go I use the Nutrifin Master Kit and my Nitrate reading starts at 5 normally and by the end of the week hits about 20 on the color chart. I do my regular water change and back down to 5 it goes. Unfortunately now the problem is after i do the water change the nitrates stay high around the 20 mark and I just can't seem to get it back down. All other reading seem to be spot on. I mean i am happy the nitrates are maintaing in the safe zone but still concern about the spike and upset in the balance.


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## 2wheelsx2 (Apr 21, 2010)

When you clean the canister filter, take out the bio media and use tank water to clean it (in a separate container of course) but you can clean everything else with tap water. With the little chlorine we have here, it should not harm much even if you used tap water, provided it wasn't freezing cold or scalding hot, in terms of preserving the nitrification bacteria. But cleaning the bio media with tank water or dechlorinated water will ensure you retain almost all of it.

As for the nitrate spike, the test kits are not super sensitive, so your nitrate could have been building up slowly, and as others have stated, maybe a fish died and added to the problem. 20% wc's don't reduce the nitrate load quickly enough. I would move to 2x50% wc a week for a while until you get the nitrate right down to 5-10 ppm. 20 ppm nitrate is not super high for freshwater anyway. Doing 50% wc makes the math simple. Do a test before the wc and if it's 20 ppm, after a 50% wc it should be 10 ppm. Doing a 20% wc will only net you a 4 ppm reduction, which with your test kit may still show up as 20 ppm (should be 16 but you maybe have started with say, 24 ppm).


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## lancergtsguy (Aug 15, 2013)

Thx 2wheelsx2, I will giver a shot.


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## lancergtsguy (Aug 15, 2013)

2wheelsx2 said:


> When you clean the canister filter, take out the bio media and use tank water to clean it (in a separate container of course) but you can clean everything else with tap water. With the little chlorine we have here, it should not harm much even if you used tap water, provided it wasn't freezing cold or scalding hot, in terms of preserving the nitrification bacteria. But cleaning the bio media with tank water or dechlorinated water will ensure you retain almost all of it.
> 
> As for the nitrate spike, the test kits are not super sensitive, so your nitrate could have been building up slowly, and as others have stated, maybe a fish died and added to the problem. 20% wc's don't reduce the nitrate load quickly enough. I would move to 2x50% wc a week for a while until you get the nitrate right down to 5-10 ppm. 20 ppm nitrate is not super high for freshwater anyway. Doing 50% wc makes the math simple. Do a test before the wc and if it's 20 ppm, after a 50% wc it should be 10 ppm. Doing a 20% wc will only net you a 4 ppm reduction, which with your test kit may still show up as 20 ppm (should be 16 but you maybe have started with say, 24 ppm).


Come to think of it I remember doing the big 50% water changes back in the day when starting/cycling my new 55g tank really threw off the chemical balance by taking all the good ammonia out and making it recycle again and again. One of the initial reasons I upgraded to the 125g was to start fresh with a bigger body of water. Just took it much slower this time round.

So my question is doing 50% wc now twice a week as suggested with a cycled tank won't throw off my tank water to the point of sending it in a major re-cycling situation as it did when I did the 50% wc when initially cycling the 55g back in the day?

Sorry for all the questions folks, Just new here and nervous to not lose any fish.


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## 2wheelsx2 (Apr 21, 2010)

Nope. There is no (appreciable) nitrifying bacteria in the water column. You can change 100% of the water if you want, which many discus keepers do, as long as the water has roughly the same parameters and is free of chlorine (pH, GH, KH, temp is close to the tank water).

When you were cycling the tank, you were removing ammonia by changing the water, which diluted the concentration, slowing down the growth of the beneficial bacteria colony which would convert ammonia -> nitrite -> nitrate.


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## lancergtsguy (Aug 15, 2013)

Nope. There is no (appreciable) nitrifying bacteria in the water column. You can change 100% of the water if you want said:


> Thx again. Much appreciated. Makes me feel a bit more comfortable to try it then. Now since it is such a big tank i use a hose attached to a tap but use prime everytime i add any water.


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## 2wheelsx2 (Apr 21, 2010)

That's all I do. I change over around 300 gallons of water a week in my 6 tanks. I only age water for my smallest tanks. I use a pump to pump out water in my 125, 100, and 46 gallons. Then straight back from the tap, after adjusting temps, adding buffers and dechlorinator.


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## jbyoung00008 (May 16, 2011)

Big water changes are more effective than smaller ones IMO and many others on here. We did a poll awhile back on Bcaquaria and most of the people with nice tanks are doing weekly 50% water changes. For some people a weekly water change is more than they can handle. Especially 50%. Which is fine IME but as long as you are doing 50% each time rather than 25% it makes a big difference. On all my tanks I do weekly but on my mom tank I perform 1 monthly 50% water change and the tank is doing very well. It has a small bio load to compensate for the once a month change. Once every 2 weeks, 50% on a regular basis is bare minimum for a heavily stocked tank IMO. Keep with that and your tank will succeed


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## lancergtsguy (Aug 15, 2013)

Thx again to everyone for the inpoot. Did a 50% last night another to be Done Friday to get the nitrates down. From that point I'll continue with the big we from now on. 

Sent from my SGH-I317M using Tapatalk


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