High Nitrate levels

[maz53]

First ..my fish are looking great, they are healthy, by all accounts. No illness or fatalities so far.
They swim around happily.
I have been running this tank for 2yrs, and recently bought a N03 test kit.
I have a 120litre Juwel
The results are that Nitrates are 100mg/l no matter what I do , I have done 30% water changes, then 10% everyday for last 3 days, I dont want to strip my beneficial bacteria with too many water changes. I treat all new water with seachems prime. I changed the filter media with new sponges.
Still the reading is 100mg/l........
I tested the kit by testing my tap water(results were zero) so the test kit is accurate.
I have lots of plants in the tank and drift wood, I pay careful attention to feeding.

these are my fish:
2 Ottocinclus (3cm each) 3 weeks in tank
1 Pearl Gourami(10cm) 2yrs in tank
1 Phanom tetra(3cm) 2yrs in tank
1 Columbian tetra(4cm) 2yrs in tank
1 Green Barb(5cm) 2 yrs in tank
2 Rosey Barbs (4cm each) 1yr in tank
4 Electric blue rams (2cm each)- 3 weeks in tank
7 Bronze Dory's (4cm each) 1 year in tank

any suggestions.......

 

[seangee]

Water changes won't affect BB, they live on tank surfaces.
Your readings suggest that nitrates are way higher than your test can measure. I would do larger daily changes until it starts to come down. Hint: If you have 200ppm and you change 30% of the water it will only come down to 140, a 10% change will only drop it to 180. I routinely change 70-80% in all my tanks every week (as a single change), but would suggest at least 50% to have a chance of seeing any difference.
Before you do this check that the pH in the tank is similar to that in your tap water (let the tap water stand for 12 hours before testing). If there is a large difference only change 25% daily to avoid pH shock. Once your tank pH reaches a similar level to your source water you can change as much as you like.

 

[maz53]

thank you so much
your advice is much appreciated

 

[Guyb93]

I’d be looking at why your tank has a constant reading of NO3 , I have a constant reading of n03 around 20-40ppm but I over feed and know why it’s there

 

[Byron]

I’d be looking at why your tank has a constant reading of NO3 , I have a constant reading of n03 around 20-40ppm but I over feed and know why it’s there

This is harming your fish. Nitrates should be as low as possible, and never above 20 ppm, and even this is serious for many fish--cichlids, for example, are now known to have problems with nitrate over 10 ppm. I intend to post more in my response to the OP which will follow.

 

[Guyb93]

This is harming your fish. Nitrates should be as low as possible, and never above 20 ppm, and even this is serious for many fish--cichlids, for example, are now known to have problems with nitrate over 10 ppm. I intend to post more in my response to the OP which will follow.

Virtual impossible for me to get less than 20ppm as my tap water has 20ppm , I have no concerns over my fish welfare my water quality it’s good enough to hve breeding cichlids that lay and spawn every 14 days and multiple pairs of breeding corys

 

[Byron]

I agree with @seangee and will just add a bit. Assuming nitrate is actually zero in your source water, then the nitrate is occurring solely from the biological system in the aquarium. The first thing this tells you/us is that water changes are likely no where near adequate, so the volume of each should be increased. Daily changes to get the nitrates down as minimal as possible, certainly below 20ppm, until you can keep them down with one weekly W/C which should still be 50-70% regardless of nitrates (though you want them as close to zero as possible, but nitrates is not the only reason for more water changes). You can read about the importance of water changes in my article at the head of this section of the forum.

Not overstocking, not overfeeding, regular substantial water changes, live plants, keeping the filter media well rinsed (all that brown stuff is organic matter), and vacuuming the substrate in open areas (this may not be necessary once nitrate is under control).

There is a false understanding of nitrates among many hobbyists. They are poison to fish, as ammonia and nitrite are, only they take longer to do the observable harm. The level of nitrate, the fish species, and the period of time the fish are exposed to the nitrate, all factor in. I discussed this subject at length with one of the most respected individuals inn this hobby, Dr. Neale Monks, and he said the evidence now indicates that nitrates tend to slowly weaken fish, making them less resilient to other problems that normally would not be an issue for the fish. There is evidence that cichlids are seriously affected by nitrates, and the experts on the cichlid sites suggest problems like Malawi Bloat may in fact be more due to nitrates than diet. The on-going harm nitrates do to the fish is not externally observable to the aquarist; fish continue to "do their thing," but they are being negatively affected internally.

All of this should not surprise us, when we realize that in the tropical watercourses where out aquarium fish have evolved, nitrates are frankly non-existent. Any level of nitrate is consequently likely to cause issues for fish, and some species are more or less tolerant of nitrate than others. One thing is clear: the lower thee nitrates, the healthier the fish. I don't know how anyone can argue against that.

 

[Byron]

Virtual impossible for me to get less than 20ppm as my tap water has 20ppm , I have no concerns over my fish welfare my water quality it’s good enough to hve breeding cichlids that lay and spawn every 14 days and multiple pairs of breeding corys

Fish will continue to eat, swim, spawn, regardless. The will to live is very strong in all animals, fish no less. This is no proof that they are not being adversely affected, and they are. Tap water nitrate is a different part of the problem, but one that others like @AbbeysDad have dealt with successfully.

 

[AbbeysDad]

Tap water nitrate is a different part of the problem, but one that others like @AbbeysDad have dealt with successfully.

Yes, I discovered very high nitrates in my well water, most likely due to the (well fertilized) 95 acre farmers field across the road. I documented this in My Nitrate Fight where I describe a filter I made/repurposed to pre-filter water using API Nitra-Zorb for water changes (that I still use today).
Now if you're sure you don't have nitrates in your source water, you may need another approach and perhaps the article Lowering Tank Nitrates will help.
One final thought...if your source water has chloramine, Prime will break the ammonia/chlorine bond and temporarily detoxify the ammonia. However, without LOTS of fast growing plants, BB will convert this into nitrites and nitrates. The point here is that in this case, large water changes just might be counter productive.
If all else fails, API Nitra-Zorb is sold in pouches intended to be placed in filters. The product works very well in adsorbing ammonia, nitrite, and nitrates. It can be recharged with ordinary salt water and reused many times. The use life can be compromised by a coating of detritus so it should be placed after all other media so it sees clean water.

 

[seangee]

One final thought...if your source water has chloramine, Prime will break the ammonia/chlorine bond and temporarily detoxify the ammonia. However, without LOTS of fast growing plants, BB will convert this into nitrites and nitrates.

I don't believe this is relevant here. OP has 0 nitrates in source water. Using prime on chloramine typically results in ammonia reading in the order of 0.25 ppm - that will never turn into an off the charts nitrate reading.

 

[AbbeysDad]

I don't believe this is relevant here. OP has 0 nitrates in source water. Using prime on chloramine typically results in ammonia reading in the order of 0.25 ppm - that will never turn into an off the charts nitrate reading.

I think it's relative to the volume of the water change and/or the volume of repetitive water changes in addition to other negative factors (e.g. compounding negatives).