High Nitrates - Overstocked?

[meloyelo]

I have a reading of 30 nitrates straight from my tap. It is well water also. With that being said, I struggle with high nitrates in my tank. The tank is cycled and I get constant 0's on ammonia and nitrite. My usual test results for nitrate in tank water are between 40 and 80 with 80 being the more "normal" number. I know that is a really bad thing. I've had to resort to doing almost 100% water changes (2 50% back to back) to get it down to any sort of reasonable number. I've had several fish die in the past 24 hours for no apparent reason. They seemed totally fine until last night. My stocking as of this morning is:

10 black skirt tetras
3 zebra loaches (down from 6)
4 pearl danios (down from 6)
6 peppered corys
2 small red blood parrots

Tank is a 55 gal with 2 Aqua Clear 70's for filtration. I do have 3 live plants in the tank to try to help with the nitrates, but they don't seem to be doing anything to get it down. I've also noticed that my PH has recently been dropping from it's normal 6.8 down to 6 between my water changes. Will to heavy of a bioload cause PH to drop like this? I guess the PH fluctuations could cause the fish to overly stress and die.

Thanks for any advice on my situation.

 

[Elitehunter1]

I think doing that big of water change that close together would be doing more harm than good in your case. Its kinda like restarting your system. It could have caused your fish to die

 

[Mab2000]

If you aren't against Having a more planted look for your tank you could try adding more. May help a bit.

 

[paulprovos]

I am ready for the lynching.......

but in my opinion if ur tap is reading 30 nitrates and ur tanks is 40 to 80 nitrates that isnt really drastic. changing that much water in 1 go?? really, i can see that being good for the fish

 

[LyndaB]

Well, your tank is overstocked and you've got some fish with large bioloads. You really need to a) upgrade to a larger tank or b) rehome some fish. Otherwise, it seems you and your fish are in this fluctuating water params scenario for the duration.

What dechlorinator are you using?

Are you putting any other chemicals in the tank?

 

[jlk]

I suspect the ph drops & jumps in your fish stress & demise rather than the water changes. A drop of .1 is enough to sicken & stress fish- a .8 drop is immense. Keep in mind the ph scale is logarithmic- each ph unit is a tenfold difference. So, a ph of 6 is 80 times more acidic than a ph of 6.8. Big difference! Then, the large water changes are raising the ph from 6 back up to 6.8. This has been more than your fish can handle at once.

I cant comment on your stocking because i have no experience with tropicals. If you are overstocked, the amount of ammonia that has to be converted to nitrate is is large (and thus the big increase in nitrate levels) and your bacteria are quickly using up the buffers in your water in order to convert the ammonia present. As the buffers are used up, your ph crashes. You can try adding some crushed coral or argonite to your filter to try & stabilize the ph & increase the buffers available but, ultimately, if you are overstocked you will need to address this situation in order to keep your tank stable. Hope this helps!

 

[meloyelo]

Well, your tank is overstocked and you've got some fish with large bioloads. You really need to a) upgrade to a larger tank or b) rehome some fish. Otherwise, it seems you and your fish are in this fluctuating water params scenario for the duration.

What dechlorinator are you using?

Are you putting any other chemicals in the tank?

I use Prime for water conditioning. Went by a huge local aquarium shop in town today. All they do is fish, salt and freshwater. Explained my situation to them. They showed me some stuff from Seachem called De Nitrate. Told them I wanted to do some research and might be back. Any experience with it?

Thanks

 

[meloyelo]

I am ready for the lynching.......

but in my opinion if ur tap is reading 30 nitrates and ur tanks is 40 to 80 nitrates that isnt really drastic. changing that much water in 1 go?? really, i can see that being good for the fish

I'll back off on the water changes. All my other paramaters are great. The high nitrate is frustrating. I'm thinking I am overstocked and it's screwing around with my PH too.......resulting in fish deaths.

 

[LyndaB]

Yet another genie in a bottle, if you ask me. Water changes will do the same thing and won't pose a possible risk to your tank.

Wait, back off on water changes? Why?

 

[Elitehunter1]

The reason you cycle your tank is so you can establish denitrifying bacteria. When you do a high volume water change you are eliminating that necessary bacteria.
You can expect a ph change when you flush your whole system like that.
Just my thoughts anyway

 

[LyndaB]

But his nitrates are through the roof..... that's not safe for the fish. Normally, I would agree about cycling and water changes, but I can't in this instance.

 

[Elitehunter1]

True but they can survive it. If it start the cycle over again then they ll die. I'd say do partial water changes to get it down. Then just treat your new water with a conditioner .

 

[jlk]

The reason you cycle your tank is so you can establish denitrifying bacteria. When you do a high volume water change you are eliminating that necessary bacteria.
You can expect a ph change when you flush your whole system like that.
Just my thoughts anyway

There is a very nominal amount of bb in your water collumn. I do very large, frequent water changes & have never had an issue keeping my tanks cycled. The bb excrete a sticky substance that allows them to adhere to all surfaces in your tank (filter, substrate, decor, etc). Water changes will not affect this.

The OPs ph is crashing before water changes due to the high volume of ammonia conversion due to the tank being overstocked. This situation needs to be addressed in order to stabilize the tank- either by upgrading the tank, rehoming some fish, or doing very frequent water changes to try to maintain a sufficient buffer level to prevent ph crashes from excess ammonia conversion.

 

[adadkins1]

I would keep doing the fairly frequent water changes. Now, don't do anything over 50% in one day and you should be safe as far as pH swings go. Maybe do 50% PWC's twice a week and see how that goes. I'd agree that if you can get some more plants they would help immensely. Hornwort, Duckweed, Anacharis, and many other plants will soak up nitrates and give you a hand.

As far as stocking, the Blood Parrots are too much and should be rehomed. If you are able to get them a new home, I don't think you would be overstocked. If you don't get rid of the Blood Parrots or get a bigger tank, you will continue to have problems.

 

[meloyelo]

True but they can survive it. If it start the cycle over again then they ll die. I'd say do partial water changes to get it down. Then just treat your new water with a conditioner .

What percent changes would you recommend? Since my tank has been cycled, I've tried doing just 50% changes twice a week to keep the nitrates lower. That hasn't seemed to work since they stay up towards 80. Out of frustration, I did the 2 50% back to back last night and it came down to 30. Since I basically did a 100% change, it just came down to the same as my tap water. Sounds like lowering my stock is about all I can do at this point.

Thanks for all the helpful input everyone.

 

[meloyelo]

I would keep doing the fairly frequent water changes. Now, don't do anything over 50% in one day and you should be safe as far as pH swings go. Maybe do 50% PWC's twice a week and see how that goes. I'd agree that if you can get some more plants they would help immensely. Hornwort, Duckweed, Anacharis, and many other plants will soak up nitrates and give you a hand.

As far as stocking, the Blood Parrots are too much and should be rehomed. If you are able to get them a new home, I don't think you would be overstocked. If you don't get rid of the Blood Parrots or get a bigger tank, you will continue to have problems.

One problem with live plants and my tank, I have LED lighting. I think I'm my own worst enemy.......

 

[meloyelo]

Yet another genie in a bottle, if you ask me. Water changes will do the same thing and won't pose a possible risk to your tank.

Wait, back off on water changes? Why?

I just meant no more back to back 50% changes. Thanks!

 

[paulprovos]

wc can only be good.. this is just my opinion, huge water changes in 1 go i dont like...just me... many do it all the time i know. ima little and often guy smaller more regular changes

 

[Elitehunter1]

I would say around 20% for each change. Get a good conditioner. 30ppm is by the book higher than you want, but I don't think it'll kill anything. Ask your fish store to test their water, I bet they are high.

 

[Elitehunter1]

Also I think it's an inch of fish per gallon. So take that into consideration when stocking