Constant Nitrate Issues

[Joyceeea]

I have a 300L freshwater tank which I've had for about 2 years, and I've always had issues with nitrate levels. My nitrate level is always around 160ppm. I try and feed lightly.
I've read multiple forums and spoken to a few different fish shops and nearly all of them have said just do more frequent water changes. I currently do a 30% change once a week.

I know that I do not have to get my nitrate down to 0 but I'm struggling to get it down at all.
I test with API freshwater master test kit.
A fish pal of mine recently gave me his canister filter to run along my current canister filter to try and help reduce it.

One of the people I was talking to highly recommended putting MarinePure and a Poly-filter pad in my filter. Has anyone had any experience with these two products and had success?

 

[fluttermoth]

Welcome to the forum, Joyceeea

Extra filtration won't solve nitrate issues. I haven't used either of those products, but I would say that you need to find out why your nitrate is so high, and get that sorted, rather than spend too much time just getting the level down (although that does need to be done too, of course!).

The reason everyone's telling you to do more, or larger, water changes, is because that IS the best way to reduce nitrate. However, as your nitrate is so high, and it's been going on a while, your fish have most likely got physically accustomed to it now and, even though we need to get it down for their long term health, we'll need to reduce it slowly so as not to shock them.

Very high nitrate levels (and, don't forget that 160ppm is the around maximum level that the API tests can register, so yours might be even higher) are almost always a sign of a tank that's overstocked, or not receiving enough maintenance.

Don't forget, also, that there are lot of other things in the tank that we can't or don't test for; fish hormones, phosphates etc, that will almost certainly be building up along with the nitrate, and water changes are the best way to reduce those.

Would you mind giving us some more details of your set up so we can help you better? Exactly what fish you have, and a complete set of test results (pH, hardness, ammonia, nitrite, nitrate) would be very useful

My best advice would be to start more frequent water changes (maybe 25 or 30% every other day) and post the extra information I've asked for and we can go from there.

I'm sure we can help you get this sorted out

 

[Essjay]

Could you also please test your tap water for nitrate so that we know how much of your tank nitrate is coming from your tap water.

 

[AbbeysDad]

AS essjay suggests, it is not uncommon these days, especially in agricultural areas, to have high nitrates in your source water so this should be tested. And if that's the case, no number of large water changes will help reduce tank nitrates! I have high nitrates in my well water due to a 95 acre farmers field across the road. I built a nitrate filter to pre-filter water I use for weekly water changes. I re-purposed a now discontinued API Tap Water Filter by filling it with API Nitra-Zorb. There are also in-line nitrate filters that accomplish the same thing...or you may need another water source for water changes.
As to tank nitrates, as mentioned filters don't help. If anything, if not serviced very regularly, they actually become 'nitrate factories' as detritus decomposes withing them.
The recommendation to use Marine Pure (or Matrix/DeNitrate) has some slight merit as the objective there is to culture anaerobic bacteria to convert nitrates into nitrogen gas. HOWEVER, although my research suggested this can be done, it is very difficult in the highly oxygenated FW aquarium. (I have unsuccessfully attempted this myself!)

To get/keep tank nitrates low the following can be important:

1) Light stock load as overcrowding creates more respiration and waste and higher nitrates.

2) Feed high quality foods sparingly. Many fish foods are made with fish meal that requires copious amounts of grain starch as binder/filler resulting in more fish waste. Higher quality foods use fresh whole fish resulting is less grain products and less waste.

3) Thoroughly vacuum the gravel well to remove detritus that decays into nitrates. Better still, switch to a sand substrate so waste and uneaten food doesn't get down under. I use silica (pool filter) sand. Others report excellent results with big box store play sand (e.g. Sacrete).

4) At the cost of perhaps better lighting, add living plants as plants use pollutants as nutrients and filter the water. Plants will also use ammonia as their source of nitrogen so the ammonia they absorb is not converted to nitrites-nitrates by beneficial bacteria.

5) Service the filter(s) regularly to get the crud out of the system. Filters help to make water look more clear, but detritus breaks down in the filter and pollutes the water column. More filters just means pushing more dirty water around. Some with larger canister filters let their filters go for months. This can be a big mistake.

We hear all the time that we need 4x to 10x GPH filtration relative to tank size. It's a myth repeated all the time! Logic tells us that good filtration is about how well we filter water, not how much [dirty] water we push through a filter. What we need is fine filtration and to get the contaminants out of the system!

As mentioned, your very high nitrates is a symptom of old tank syndrome. Fish can slowly adjust to pollution so a change to [more] pure water needs to be done gradually. Rapid changes in water chemistry can kill (although a rapid change to better water is less stressful than the reverse).

Good luck and keep posting!

Tank on,
-Mike

 

[Byron]

Welcome to TFF.

I agree with most of what other members have posted. You first need to test the source water (tap water) on its own to see if any nitrate is entering this way. Mike has expertly covered how to deal with that. If nitrate is occurring solely within the aquarium, you can deal with this and others have mentioned how. A much larger water change would be a first step, 50-60% of the tank volume once a week (at one time, this is more effective than smaller more frequent changes) but if nitrate is in the source water this obviously isn't the whole answer.

One thing I do not agree with is slowly reducing nitrate to avoid shock. Nitrate is a toxin like ammonia or nitrite; it just acts slower and depends more on the level, period of exposure and fish species, as well as the age of the fish. But it is still a toxin, and the sooner it is removed or lowered the better. Fish do not build up any sort of resistance or resilience to nitrate, or become used to it, any more than they can to ammonia or nitrite. With nitrate present, they are being affected, and like all toxins you want to remove it immediately, as much as possible.

The effects of nitrate are not that well understood. Neale Monks described it to me as a continual weakening of the fish. The level, duration of exposure, fish species and age factor in as to how detrimental the nitrate may be long-term. But nitrate is now being counted as a significant factor in several fish problems such as bloating in cichlids.

We must also never forget than in nature, nitrate in freshwater and the oceans is next to zero. Fish have evolved to function best in such environments, and will obviously have some problems as nitrate appears or rises. Nitrate is also more toxic in salt water.

Byron.

 

[AbbeysDad]

Let me clarify. Old tank syndrome is well documented in that fish can adapt to slowly polluted water and appear to be fine...even breed. Some hobbyists are convinced and even brag about not doing water changes. Sometimes these same hobbyists will confess that any new fish they add don't survive and it's a mystery to them because they've had other fish a long time (which to them might be several months or a year! [when the average tropical fish could live about 10 years]). The problem is that [new] fish can easily succumb to drastic [especially negative] changes in water chemistry. All due respect to my friend and mentor Byron. However, I honestly don't know the results of taking a fish from a water very high in nitrates and putting them directly into pure water...but I would opt for more gradual change. Having 'said' that, as with the "plop and drop" acclimation method, it's been said that it can take fish days or even weeks to acclimate to new water chemistry, so perhaps the 'shock' of fresh/pure water isn't so bad.

 

[Byron]

Before responding I ran this past my friends Neale Monks and Bob Fenner. In a nutshell, they both agree with my reasoning.

The issue with "old tank syndrome" involves pH and ammonia (primarily). The pH generally lowers below 7, and ammonia is ammonium. Massive water changes that raise the pH above 7 cause the ammonium to change back into ammonia. To avoid this, as well as to minimize pH shock itself, smaller water changes over a period of days are advisable. But nitrate is not a factor in this scenario.

Nitrate is toxic to fish, and like any toxic substance, removing it as rapidly as possible is always the best course of action. Second, fish cannot "adapt" to toxins. The fact that they do not turn belly up like they would with ammonia or nitrite or at minimum show obvious signs of severe distress is because of how nitrate affects them. As I mentioned initially, the level and the period of exposure, along with the species and the age of the fish all factor in. But nitrate as high as what was mentioned in this thread (160 ppm) is detrimentally affecting the fish, and the sooner they are out of that "poison" the better.

Neale also provided some comments on the issue of "adapting" fish to varying parameters, which you (Mike) mentioned, and noted that this is not as simple as some may believe. He agrees that any drip acclimation is likely pointless, as fish take weeks to adapt, if they even do in some cases.

I provided this summation to Neale and Bob:

So what I take from both of you is that with the proviso that parameters (GH, KH, pH , temperature) are close enough to be called the same, a large water change to reduce nitrate from 160 ppm down to 10 or 20 ppm is not going to harm the fish, and is more advisable than doing smaller changes over weeks.

Neale replied, "I would 100% agree with this," and Bob called that statement "a good summation." Neale stated "if the new water was similar enough to the old [in terms of pH, hardness and temperature], doing 90% water changes has been demonstrated to be perfectly safe in and of itself."

Byron.

 

[AbbeysDad]

I have read repeatedly (and believe) that [very] high nitrates are always a factor in old tank syndrome. I have no names to drop but here is an article advising against rapidly changing the water chemistry. Food for thought.

 

[Essjay]

One thing I have picked up from this discussion is that Byron and his colleagues say that a big water change is fine provided that pH, GH and KH are almost the same in the tank and tap water; and that AD's link comments that in old tank syndrome, the pH has usually dropped below the tap pH.

Perhaps the advice should be - with high nitrate a large water change should be done if the pH has not changed significantly from the value in tap water but that if the pH is significantly different, smaller water changes should be done?

 

[Byron]

Yes, I do not known how/why old tank syndrome crept into the issue; the issue raised in post #1 by Joyceeea was how to lower nitrates of 160 ppm. Advice from two members, and members with considerable experience, mentioned that nitrates should be lowered slowly over time, and with that I disagreed.

We are not dealing with old tank syndrome, or with parameters out of whack. Only nitrtates. And there is nothing in the linked article that counters my on-going advice about nitrates.

 

[AbbeysDad]

Yes, I do not known how/why old tank syndrome crept into the issue; the issue raised in post #1 by Joyceeea was how to lower nitrates of 160 ppm. Advice from two members, and members with considerable experience, mentioned that nitrates should be lowered slowly over time, and with that I disagreed.

We are not dealing with old tank syndrome, or with parameters out of whack. Only nitrtates. And there is nothing in the linked article that counters my on-going advice about nitrates.

As you know I have a long history of fighting nitrates and even before I pre-filtered water to remove nitrates, I never saw nitrate pollution as high as 160+ppm!...... So I 'crept' old tank syndrome into the conversation as to me, the very high nitrates suggest that or something similar enough for a similar resolution. Suffice it to say that something is very, very wrong for such high nitrates to persist, especially after repeated partial water changes.

 

[Byron]

Agree, which is why the data various members have requested earlier in this thread needs to be provided. We need to confirm the exact nitrate level (if 160 ppm is correct, or was the testing faulty...Regent #2 has to be shaken for a good 2 minutes not 30 seconds or the reading will often be much higher than actual), what if any occurs in the source water. What is the pH of source and tank water. What are the fish. Without the data we are guessing.

 

[Joyceeea]

Thanks everyone for your responses!!
Sorry it's taken me a while to respond.
I did a test on the source water and it's:
PH - 7.6
HR-PH - 7.8
Ammonia - 0.50ppm
Nitrite - 0ppm
Nitrate - 0ppm

I tested the tank water again
PH - 6.6-6.8 (couldn't tell which)
HR-PH - 7.4
Ammonia - 0.50ppm
Nitrite - 0ppm
Nitrate - 80-160ppm (couldn't tell which)

My test kit doesn't have a test for GH OR KH so I'd guess I'd have to buy another test for that.

In the tank I currently have:
- 2x bloodfin tetras
- 1x small clown loach
- 2x torpedo barbs
- 2x medium Siamese algae eaters
- 1x large bristlenose
- 2x med-large koi angels (breeding)
- 1x rummynose tetra
- 5x green tiger barb (added around 2 months ago)

I feed them Sera San tropical flakes and Hikari algae wafers

I clean the gravel every water change but it's hard to get to some places due to plants and lava rocks.

Regarding AbbeysDad's mention of cleanin the filter, how often should the filter be cleaned? And what should it involve?

Thank you for you help so far

 

[Byron]

First on the nitrate test, make sure you shake Regent #2 for at least 2 full minutes; the 30 seconds suggested in the instructions is not sufficient, and this can cause inaccurate high readings. And this 2 minute shaking is the Regent bottle itself, before adding the drops to the testy tube of tank water. Test doing this and see if the number lowers.

As for GH/KH, check the website of your municipal water authority, this data may be posted. Or call them and ask. No point in wasting money for a GH/KH test you may only do once. I am suspecting the GH/KH to be low rather than high, meaning softer rather than harder water, but you need to confirm.

On thee pH, use only the regular range test, not the high range. The results will differ, but given the numbers the regular range is what you want to be using. Using booth only confuses things, as one (the high here) is not accurate.

Water changes need to be increased. Half the tank volume once each week, minimum. I do 60-70% once a week. I have a relatively heavy stocking of fish in some tanks, but the nitrate remains 0 to 5 ppm. As your tap water is free of nitrate, it is occurring solely within the aquarium.

Mike and fluttermoth provided good advice on nitrate reduction. As for cleaning the filter, do this as often as it seems to require it, and probably more frequently than at present. The brown gunk that accumulates in the filter is organic matter, and this is where nitrates originate. Same with the substrate; the more organic matter you remove, the less nitrate should accumulate. Be careful not to overfeed. The fish load shouldn't cause nitrate issues.

There is not much scientific data on nitrates and ornamental fish as most studies have been concerned with commercial fisheries. Goldfish have been studied and nitrate at 100 ppm and above does seriously impact their health. Tropical fish can be expected to be more sensitive, and nitrate above 20 ppm is now being suggested as the cause of some problems with cichlids. Nitrate should always be kept as low as possible.

Last comment not really related to nitrate but still pertinent is on he fish stocking. You have some pending issues. I would remove the Tiger Barbs; this species needs a group of at least 10 to hopefully avoid their aggressive tendencies, and they should never be combined with sedate fish like angelfish. Such combinations inevitably cause stress to fish, and this weakens them (much as nitrate does) so they are even more susceptible to all sorts of things--including the nitrate. Everything is related.

Edit. Just saw I missed a couple of other serious stocking issues. Clown loaches need a group of five-plus, four can sometimes work (they are highly social, and form an hierarchy) but as they reach 8-12 inches they need at absolute minimum a 6-foot (180 cm) tank and preferably 8 feet. The tetras need a group of each species, minimum six but more will be better when space allows, and rummynose do much better with at least 12.

 

[SeanTrollope]

yes i must agree we do need to discuss a few stocking issues. firstly the barbs are not suitable for most of the fish that you have in there, especially the angels. secondly there are a host of fish mentioned that need large schools of 8 + to be happy in there environment. i might be wrong but i think that you have too many large bottom feeders in my opinion, but that could be that we are not sure of the exact dimensions of the tank.