Can't reduce Nitrate levels

[jmadden93]

I have a 125gallon fish only tank with tons of live rock. It's been running for 2 years so cycling isn't an issue. I've never had a lot of fish in there and currently only have 1 med foxface, and about 8 small fish (2 small wrasses, and 6 green chromis). I feed them once a day and they eat everything I give them.

I've been okay (although I could have been better) about regular water changes. I've done about 40 gallons of water changes in the last two weeks (2x20gallon) and still my nitrate levels are around 20ppm. I even vacuumed the gravel while doing these water changes and though i got a lot of decaying matter out. I've even changed out the blue foam mechanical filter that the water trickles over before going into the sump.

I feel like my nitrate levels never drop below 20ppm. Any idea what I'm doing wrong? Could my sump need cleaning out? My skimmer is plenty big enough and seems to be working great (filling up the collection cup every 3-4 days).

Any input you can give would be appreciated!

I'm using the API nitrate kit and follow instructions exactly. Here is the chart:

 

[Mavrk]

1. Are you using RO/DI or tap water?
2. Do you have a lot of algae?
3. How deep is your gravel?

The quick answer is more frequent water changes. You say that your nitrates are always at 20 ppm. This means that your water changes are enough to maintain that level of nitrates. So the amount produced between water changes is the amount you are removing. The reduction of Nitrates from water changes is directly proportional to the percent water change.

That is to say if you do a 20% water change, then your nitrates will reduce by 20% (if using RO/DI water). So if you are at 20 ppm and you do a 20% water change, your nitrates will be at 16 ppm which still reads as 20 ppm on your test kit. If you then do an immediate 20% water change, your nitrates will be at 12.8, etc. However the reality is that a week later, your nitrates will have gone up, so it will be higher than that.

Throughout this process, your test kit will still read as 20 ppm as long as it is below above 10 and below 40 ppm. For all you know, your nitrates could be at 30 ppm with that test kit and it will take even longer to reduce the nitrates.

Other things that can help are macro algae, a deep sand bed, and feeding less (or removing fish). Personally I don't believe in starving fish. Macros are good, but can take a while to work. A deep sand bed takes time to become established. Therefore, all I can say is to do more frequent water changes. If you do a couple large ones close together, you will see a faster drop. Don't worry about losing bacteria, most of it is in the rocks and substrates with very little in the water column.

 

[Floowid]

Look for pockets of trapped detritus like in the overflow, nooks and crannies of the sump, bio-balls if you have them, look anywhere crap can build up. You will be surprised where it can be hiding. You may also want to take a powerhead in hand and blast out behind the rockwork etc. Be careful what you disturb in a 2 year established tank however.

Look for those pockets of poo, and do some big water changes in quick succession.

With all that said, 20ppm is not that bad for a fish only tank.

 

[Mavrk]

By the way, you may get some suggestions about vodka dosing. While this works, it should only be done after researching everything about it. Personally, I have never dosed vodka.

 

[Mavrk]

With all that said, 20ppm is not that bad for a fish only tank.

I totally agree. However, I can understand why you would want it to be at 0. It looks like you have a routine that keeps the nitrates at a constant amount, so if you got it down it should stay down.

 

[DeepSeaBeauti]

Vodka!!!! I love this method, i tell everyone about it. Obviously you want to find out where your main source of nitrates are coming from.. Looks like everyone has covered most of them, but in the mean time read up on doseing vodka. It did wonders for my tank. I was having trouble with high nitrates and phosphates. My nitrates are zero, and my phosphate is coming down. Read this forum..... its the best tool!

 

[juicesay]

Why don't you try running a nitrate reactor.

I've had a lot of great success with it.

2 Chambers, 1 Sulfur 1 ARM media to neutralize the effect.

Once everything returns to the tank it's all safe enough to drink.

 

[jmadden93]

@MarkV: I use only RO/DI water, and a 3-4 inch layer of crushed coral & sand. I have a fair amount of algae. I wouldn't say it's a lot.

I'm not too familiar with DSB and would like to try that route, but I dont know if my mix of coral & sand is fine enough.

To do an effective water change is it necessary to vacuum the gravel or is simply replacing water off the top of the column enough?

 

[jmadden93]

Vodka? I've never heard of that method but it sounds fun. How much of it do I have to drink before the nitrate levels fall, or do I just keep drinking until I cant read the chart anymore?

I'll look into that method. Thanks! You learn something new everyday.

 

[jmadden93]

@FloowID & Markv: I hear you about the PPM levels. I have had trouble keeping a lot of the fish I've bought over the years as they die anywhere between 1-10 days. I figured my water quality might be an issue, but I think I also was picking fish beyond my skill level.

I wanted to make a serious push to get my tank in excellent health and start on good maintenance habits. That's what prompted me to start being more serious about water quality.


I've never used a nitrate reactor. Do they help? I've also heard that mangroves are a good thing to help reduce nitrates. Any experience & thoughts to share on that?

Thanks all!

 

[LaOtIn]

+1 on the Vodka dosing

heres the steps:

1. dose thyself with Vodka
2. sit thyself in front of thy tank
3. dose thyself more
4. watch tank and the nitrates problem will disappear from thy mind!

woot!

problems: when you sober up you may have a hangover and you will remember that you still need to do something about your nitrates!

hahahaha, sorry i couldnt resist! ever since i started seeing vodka dosing posts

on the real:

+1 on the nitrate media reactor. i am seriously considering a nextreef MR1, getting a divider for it and doing half Seachem denitrate and half something else, not sure yet

 

[jjsan]

As previously suggested, vodka, nitrate reactor, Bio pellets like Warner Marine, NP, Reefing Evolution, Vertex, etc may help.

 

[disenchantedone]

Hey jmadden93, a FTS of your setup would help. +1 on Mavrk's info. A few things BRS had me do that helped me understand my water quality were:

1. Check the expiration date of your test (For API, the last four digits stand for month and year, I believe)
2. Test your RO/DI water
3. Test your Freshly made salt water
4. how often are you feeding?

If your test is fine, and you isolate Nitrates in your RO/DI or Freshly made saltwater, then water changes won't help you until you clean up that first. Regarding feeding, I now use limpitsreef's instructions on youtube to make my own food. He also advised fewer feedings, which helped with my nitrates.

Also, a DSB bucket really helped me manage my nitrates as well. Goodluck!

http://www.americanaquariumproducts.com/Nitrateremoval.html
http://reefcentral.com/forums/showthread.php?t=595109&page=7

PS: +1 on the mangroves and chaeto, but you have to use a lot of mangroves to make a difference. If you do, use a plant bulb from Homedepot, and spray your mangroves with fresh water once a week. They'll grow like mad. But be careful about mangroves decaying and polluting your water as well. All the nitrates supposedly get absorbed by the plant and the leaves fall off. Find all of those leaves and throw them away or else you'll pollute your tank.

 

[Mavrk]

Just to help you on your research of vodka dosing:
http://reefkeeping.com/issues/2008-08/nftt/index.php

For the record, I still say do some frequent large water changes to get it down. Then do frequent smaller ones to keep it down (10% a week is normally okay).

 

[Eric45]

I've dosed vodka for several months and found that it did reduce my nitrates to zero. However, I also felt it had a negative effect on my anemone and soft corals. The SPS looked better presumably from the reduced nitrate. In the end, I've chosen just to live w/some nitrate in the tank and see what happens. One thing for sure, the anemone and sofites never looked better.

 

[blasterman789]

I've done about 40 gallons of water changes in the last two weeks (2x20gallon) and still my nitrate levels are around 20ppm.

That's because your tank has hit equilibrium, and even if you did a 50% change your nitrate readings would be back up in a few days. This is a common problem with established tanks.

I have some disagreement with the comments above and agree with others. First thing I would do is test your freshly mixed water for nitrate.

Next is to scrub all external surfaces, filter pads, the inside of your skimmer, sump, etc. Grungy build-up on these things act like a nitrate factory.

Next, get a turkey baster and blow out all the surfaces of your live rock. After awhile the surfaces clog up and deeper nitrate eating bacteria can't get food.

This alone might knock your nitrate readings in half after a month.

Last, I'm wondering if you have anything growing in the tank that's consuming nitrate. Xenia, zoas etc., will thrive with nitrate readings over +10ppm. Personally I'm not a fan of competiting macro algaes because they are just one more thing to take care of.

 

[lars on live]

A turf scrubber or a good fuge setup could help some, but might need more info about your setup to be able to say for sure.

 

[Felixc395]

I might try n/p biopellets or some other form of beneficial bacterial proliferation. The bacteria process and breaks down nitrates and phosphate in your aquarium so more is always good I guess.

 

[Mavrk]

That's because your tank has hit equilibrium, and even if you did a 50% change your nitrate readings would be back up in a few days. This is a common problem with established tanks.

I have some disagreement with the comments above and agree with others. First thing I would do is test your freshly mixed water for nitrate.

Next is to scrub all external surfaces, filter pads, the inside of your skimmer, sump, etc. Grungy build-up on these things act like a nitrate factory.

Next, get a turkey baster and blow out all the surfaces of your live rock. After awhile the surfaces clog up and deeper nitrate eating bacteria can't get food.

This alone might knock your nitrate readings in half after a month.

Last, I'm wondering if you have anything growing in the tank that's consuming nitrate. Xenia, zoas etc., will thrive with nitrate readings over +10ppm. Personally I'm not a fan of competiting macro algaes because they are just one more thing to take care of.

Not sure what parts blasterman agreed with and disagreed with. But the extra cleaning is a good idea. I was also thinking that the crushed coral (vs oolitic sand) might be adding to things.

Here is an interesting way Marc (Melev) suggested to do a major water change without shocking the inhabitants http://www.melevsreef.com/reducing_nitrates.html:

If your tank is suffering from high nitrate levels, the success of your reef will depend on your being able to get this under control. Changing 100% of the water would be the ideal, but it may shock your corals, fish and invertebrates in the process. A more gradual way is recommended.

Example from my 55-gallon Reef : Make up 20 gallons of fresh saltwater in a trashcan in front of your tank. Drain 10 gallons of tank water into the 20 gallons of new water, and let that mix. Pump 10 gallons of that water back into your tank, and let the power heads mix that water up in your tank for a minute or so. Then repeat this three more times. Dispose of the now polluted 20 gallons of water. Make up another 20 gallons of fresh saltwater, and repeat this procedure. As long as your temperature and salinity match the tank, your inhabitants won't be affected adversely, and with each rotation of water, the nitrates are being diluted and removed from your tank.

Simply pulling out all of the water in one massive water change puts stress on your entire tank. Doing small water changes consistently won't bring nitrate levels down. At best, it will maintain them at their current levels. Using the example above, a tank that was at 80ppm would be around 30ppm after a couple of hours work and your population will be happy and unaffected. Once your nitrate levels drop, they are easily kept low with regular water changes, as well as the use of a DSB and macro algae.

Your tank will be healthier, your reef happier and the nitrate problem fixed!

 

[ironwill723]

I have a 125gallon fish only tank with tons of live rock. It's been running for 2 years so cycling isn't an issue. I've never had a lot of fish in there and currently only have 1 med foxface, and about 8 small fish (2 small wrasses, and 6 green chromis). I feed them once a day and they eat everything I give them.

I've been okay (although I could have been better) about regular water changes. I've done about 40 gallons of water changes in the last two weeks (2x20gallon) and still my nitrate levels are around 20ppm. I even vacuumed the gravel while doing these water changes and though i got a lot of decaying matter out. I've even changed out the blue foam mechanical filter that the water trickles over before going into the sump.

I feel like my nitrate levels never drop below 20ppm. Any idea what I'm doing wrong? Could my sump need cleaning out? My skimmer is plenty big enough and seems to be working great (filling up the collection cup every 3-4 days).

Any input you can give would be appreciated!

I'm using the API nitrate kit and follow instructions exactly. Here is the chart:

I use the same API test kit. Read your instruction booklet on the nitrate test section. If I remember correctly you need to divide the reading number by 4.? something to get the correct reading. So if you reading says 20 your actual nitrate level is like 5. API tests are different than a lot of kits in how they are measured.