Out of Control Nitrates

[JoeShuck]

I am going nuts trying to reduce my nitrates. Currently all other parameters are in check: PH=8.3, Phosphates are near 0(undetectable), Calcium=500, dKh=10, mag=1500, but my nitrates are 180+. This tank has been running for around 7 years, and for many of those years it was ignored and horribly maintained. There were a few corals in it that eventually died...the tank wasn't skimmed and water changes were maybe 4x per year. Yeah...I know.

I have been restoring the tank over the last few months and it has been going better. There was a bunch of algae on the rocks, and the CUC is making quick work of that. Coralline is coming back quickly and the lone fish: Randalli Goby + Tiger Pistol, are still cruising around. The tank is 65g tall with 20g sump and refugium. I just switched back to my SWC160 skimmer after getting a new pump for it; switched from a new Octo Classic 150s which wasn't skimming as well as I had hoped. I am running a biopellet reactor out of a phosban150(1/2 full).

I can't keep chaeto alive at all...just browns and disintegrates under the strong grow lights above it. I have done large water changes to drop the nitrates in the interim. I have vacuumed the deep sand bed to try and get rid of any leftover organics in the system.

The skimmers are barely pulling out anything, even having the BP reactor output right up to the intake of the skimmers. I see no bacterial blooms in the tank, so my assumption is that the BP reactor may be not working as well?? I have been running it for 1.5 months now, with no definitive reduction of nitrates. I have a few cheap frags in there mainly just to give me an indication of water quality, and they are doing okay, sans a single zoa that didn't take.

Sorry for the super long post...just get seem to wrap my head around what is happening - where the nitrate source is.

[nereefpat]

Well... you'll have to do water changes to drop the nitrates. The bigger the better.

No reason you can't change at least half the water a couple times a few days apart.

[Dan_P]

I hope things work out. Here are soe ideas.

Nitrates come from ammonia which come from fish and bacterial decompostion if organic matter. Since you only have two fish, I would assume you have organic matter being consumed. You may also have low or no denitrification going on.

One thing I wonder about is the vacuuming of the substrate. That could have greatly disturbed denitrification in your system, reducing nitrate consumption. Also, in turning over the substrate in the vacuuming process, organic matter might have been buried, generating ammonia that was oxidized to nitrate. It could take awhile to digest this buried organic matter.

Also, a substrate can contain ammonia where oxygen is low. When the substrate was vacuumed this ammonia was probably released to the aquarium and oxidized to nitrate, probably a small but measurable amount.

The bacterial community of the aquarium was given a jolt when the substrate was vacuumed and may take a while to reestablish itself. It may also not reestablish the orginal community before the vacuuming but this might not be a noticeable change.

Why the Chaeto is being so fussy is a tough one to answer. It is possible to starve algae through growth of something else. Clearly, it is not nitrate limited, but bacterial growth and maybe phytoplankton growth are causing other micronutrients to become limiting, like iron.

I recently started to look more closely at the water in my fish only aquarium. I was surprised by the number of organsms and biomass in the water and yet not coloring the water. I estimate this material is enough to produce at least 10 ppm of nitrate if they died and were consumed by bacteria. My study is just starting but I’ve already noticed a shift in phytoplankton after dosing with vinegar. Is it caused by dosing or was it going to change anyway? At this point, just food for thought.

[bertoni]

If water changes haven't worked so far, I might try dosing a bit of phosphate to see whether that helps with the bio-pellets. In theory, the reactor can be limited by the availability of phosphate, although we don't have the tools to check that. I'd also measure the nitrite level, if I had a kit available. Nitrite will confuse nitrate test kits, although very few tanks measure any nitrite for any significant length of time.

You could consider diluting a sample of tank with some fresh saltwater to get a better idea of the nitrate level. A dilution of 3 parts fresh saltwater to 1 part tank water might be enough. After that, a series of 20% changes might be useful, but we need to get a reasonable idea of the nitrate level so that we can tell whether the system is still producing a lot of nitrate.

[gprdypoo04]

In my case I've always had a nitrate level of 40 to 50 ppm even when newly set up. Never had a lot of fish or invertes or overfed in those early days. Now the fish are bigger and of course more food. I never vacuumed the sand but of course it has been moved around a bit over the years. My phosphate levels have always varied a bit. I've been running biopellets the last 6 months and does nothing to reduce nitrates or phosphates. I put about 30 to 40 mos of vinegar in with my kalk. Nitrates don't move.
If I do a water change say 50 percent then my nitrates drop a little but always come back up. To keep at a lower end i would have to constantly change the water and that's probably not being where most want it.

[josephxsxn]

I used to have 50+ ppm and could never get it down. I built a sulfur denitrator and it was one of the best additions ever, I never get above 4ppm now with heavy feeding.

[Dan_P]

Originally Posted by josephxsxn

I used to have 50+ ppm and could never get it down. I built a sulfur denitrator and it was one of the best additions ever, I never get above 4ppm now with heavy feeding.

Any idea why your system’s nitrate level was high?

[Dan_P]

Originally Posted by gprdypoo04

In my case I've always had a nitrate level of 40 to 50 ppm even when newly set up. Never had a lot of fish or invertes or overfed in those early days. Now the fish are bigger and of course more food. I never vacuumed the sand but of course it has been moved around a bit over the years. My phosphate levels have always varied a bit. I've been running biopellets the last 6 months and does nothing to reduce nitrates or phosphates. I put about 30 to 40 mos of vinegar in with my kalk. Nitrates don't move.
If I do a water change say 50 percent then my nitrates drop a little but always come back up. To keep at a lower end i would have to constantly change the water and that's probably not being where most want it.

I did some back of the envelope calculations on your system’s nitrate level.

45 ppm nitrate is equivalent to 10 ppm ammonia nitrogen. The source of ammonia nitrogen is food and assuming the nitrogen content of your feed is 7%, that means 145 ppm dry wt, or assuming 80% water content, 725 ppm wet weight or 1343 mg per gallon of food was consumed to bring the system from 0 to 45 ppm nitrate. To put 1343 mg/gal in perspective, thats about one third of a frozen mysis cube.

A fifty gallon aquarium, for example, with a once a week 50% water changes would only need 50 * 1/6 of a mysis cube (8 mysis cubes) to bring the nitrate level from 22 to 45 ppm. Not so much.

This calculation points to something interesting. Denitrification in your system seems to be very sluggish. More generally, the system’s nitrate export is too low. Why is another problem to tackle. Starving your fish though is not the answer.

[Ridethewave]

I’m wondering why your dsb isn’t working. Mine dropped my nitrate from 50 to 0 in 6 weeks when I added it and it’s been less than 2 ever since. Do you have good water movement ? or perhaps some other filter media acting as a nitrate factory?Get the surface water moving. Skimmer working, feed the fish and some large water changes.
Are you sure your test kits ok?


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[JoeShuck]

This is all great info. I figured the vacuuming of the sand bed may release some/too much gas, so I really only dabbed it a bit to pick up any bits of algae and crap that was laying there since I turned the flow off for the water change. I do have a plenum (I think 1.5-2") that the rock is sitting on and, of course, is buried under another inch or so of sand. The sand bed is likely 3.5-4 inches at its deepest point, and really only fluctuates an inch or so in depth, around the tank. Either way, even the slightest stir of the sand can release toxic gases and disallow the sand bed from its anaerobic benefits; so, definitely keeping an eye on that.

The ability to keep chaeto(or lack there-of) is seriously what is killing my ability to turn off my analyses of the tank's bio-systems. I went home last night and added another grow light that was more directional than what I had on it. I am hoping that, for some unknown reason, the ability for the algae to convert the organics was somehow due to the tank lights overpowering the sump/fuge lights and giving too much leeway to the algae in the system. This is a crutch, I know, as the remaining algae in the display is disappearing faster than I have ever seen. This tells me that something is working, and something else is hiding behind me still, all while kicking me in the rear and laughing.

I am ordering new test kits, even though the one I have was brand new, but it's an API, so...well, you know. I know my water is great (vertex RO/DI w/dual TDS), and I use a handheld TDS meter to test it again once it has been churning in my mixing tank for an hour or so.

Flow wise, I have 4 outlets in the display for the return lines |:T:|
I am going to try and dilute the water, as recommended above, and see if I can get an actual reading of the nitrates. I have been dosing Microbacter7 daily as well, and will continue, but I am beside myself with this damn thing. Half tempted to restart>new tank>all new fun stuff...but my wife lives with me...

[JoeShuck]

Flow wise, I have 4 outlets in the display for the return lines |:T:|
< that's my drawing. The 'T' is the overflow. The return pump is an Eheim ?1280? whatever the one is that is 900~gph, also have a MP40 and Jebao RW15, as well as a Hydor mini/nano that I keep right at the top to churn the surface. One of the return outlets is locline raised above the surface and acts like a fountain/waterfall of sorts, also to churn the surface.

[JoeShuck]

Sorry for the multi-weird posts. I tried to edit my first reply, but I don't have the option yet. Is there a post # requirement in order to edit your replies?

[bertoni]

I am not sure about the editing issue. There might be a lower limit on the number of posts, to control spammers.

[yacn]

following along....and adding my similar experience....and still trying to figure out what to do next....LOL

150 gallon DT is 10+ years old....6" deep sand bed using crushed coral....poor maintenance some years. Very high nitrates 160+ and couldn't keep chaeto growing in sump even when using different lights. Have either used reef octopus skimmer xl 2000 skimmer or Reef Dynamics 100 skimmer. All other parameters were pretty normal except phosphates were high and magnesium was always low.


I have mainly mushrooms, polyps and about 15 fish. Some of the fish died over the years but the mushrooms and polyps have multiplied like crazy in the high nitrate water.

I took out chaeto and lighting from sump 2 years ago.

I started Vodka dosing and began to see nitrates drop, but traveling for work made me switch BP reactor for the past 2 years and I haven't seen any real changes in nitrates....but I blamed it on poor maintenance. I went 6 months or longer w/o water changes.

I've vacuumed out all the crushed coral over several months to not shock the system, and now have bare bottom tank. I also vacuumed out all the sand & crushed coral (2 inches) out of my 40 gallon sump.

I've done (3 to 4) 40-50 gallon water changes over 2 months.

Nitrates are now at 120 Phosphates are 1 or 2...can't remember exactly at the moment.

I just added Maxspect 250 gyre in DT. Kicks up ton of detris!! Hoping this will help.

I also just ordered an ATS scrubber from Bud. Hoping this will be the golden ticket!! 2 month wait to get it though.

I am considering buying a doser and going back to vodka or even vinegar dosing instead of BP. Thinking of dosing Alk, Ca and Mag too. Just not that familiar with dosing.

In the meantime will continue to do large and/or frequent water changes. I'll try to keep you posted.

[gprdypoo04]

I just did a 50 percent water change, scrubbed my rocks a bit and no reduction in nitrates. Bio pellets for about 6 months now.

[bertoni]

If the substrate is gone and the nitrate level still bounces back up quickly after water changes, then I suspect that the problem is too much food for the system, or some sort of artificial bio-media. Better skimming and more live rock can help in a lot of cases.

[yacn]

the substrate is gone and the nitrate level still bounces back up quickly after water changes, then I suspect that the problem is too much food for the system, or some sort of artificial bio-media. Better skimming and more live rock can help in a lot of cases.

If this was directed at my post. I forgot to mention I took out the bio balls from my sump 2 years ago, and added a large Marine Pure Block in my sump. Nitrates were already 160+ so I was desperate to try other methods. The block is still in my sump. I have a leather and has been doing great!!

I also have 150 pounds of live rock in my DT.

I don't think I'm overfeeding. I feed the fish every other day to every few days, either green seaweed sheets (one large sheet) or frozen food (combo of mysis, brine and cyclops)

I'm really hoping the ATS will solve this problem and better maintenance moving forward. Still considering dosing too....but going to wait a bit before adding that.

[Rover88]

Big water changes. 50%, every few days. This will work, period end of story...

The only issue is whether your nitrates are a gradual build up from years of neglect, or a more immediate source filling the tank with them. But were I in your shoes, and I didn't see any large sources of nitrates (like an inch of detritus, or a rotting fish) I'd just do a few massive water changes and test. Once its reasonably low, test every few days to make sure its not climbing back up. If it is, feed less or clean out more detritus.

[yacn]

thanks....I'm doing water large water changes. More like weekly instead of every few days

Syphoning out as much detritus as possible when I do.

I guess I continue to do that until they come down to a normal reading.

[Rover88]

Originally Posted by yacn

thanks....I'm doing water large water changes. More like weekly instead of every few days

Syphoning out as much detritus as possible when I do.

I guess I continue to do that until they come down to a normal reading.

It can take a while... If you start with 180 for example...

Changes
0: 180ppm
1: 90 ppm
2: 45 ppm
3: ~23 ppm
4: ~11 ppm
5: ~6 ppm
6: ~3 ppm

It can take 6 50% changes to get below 5ppm.... IF the system is not producing a surplus anymore.

[JoeShuck]

I have been doing quite a few water changes, but more gradual as I am hoping that there is no more surplus leaching. 20-30% twice a week, or so. This is really not effecting the fish or corals much, referring to the higher nitrates, and it seems that my chaeto isn't dying off as fast anymore. It may have even hit a point of stability in growth...or maybe just stasis.

Oddly enough, now I have a strange issue of high PH. I have never had that problem before, but am trying to mediate it with cutting back the ml's of alkalinity and calcium dosing. I tested 2 days ago and my dKh is at 11.5, and calcium is 520. Magnesium I have tried to taper a bit since it was at 1600 for a while and my snails are "sluggish". Now have it at around 1350-80, and am dosing 20ml's of Brightwell Magnesion per day. I haven't tested it in a few days, but it was holding steady with that schedule. But the PH is tripping me out. I have since removed my filter sock to engage more turbulence and closed the windows to attempt at increasing the surrounding CO2 levels. Just weird. I am staring at my Apex dashboard right now and it is still at 8.58...

[bertoni]

8.58 is safe, but I'd start checking. How long has it been since the probe was cleaned and calibrated?

[five.five-six]

11.5 is pretty darned high. I start taking corrective action at 10.5 or lower.

[JoeShuck]

Originally Posted by five.five-six

11.5 is pretty darned high. I start taking corrective action at 10.5 or lower.

Oddly, this is what Reef Crystals mixes close to. I have had 2 buckets of RCs and they have both mixed really high. To be a contrarian, there are plenty of cases where tanks run upwards of 13-14 and have not had any problems. Some even say it accelerates the growth of the corals. BRSTv is currently doing a "BRS Investigates" episode to test this very idea; however, I have already switched back to Salinity to make some of these changes to a more comfortable zone.