Nitrate issues in 300g fowlr tank

nldemo

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Hello!

I am battling a nitrate issue in my 300 gallon fish only tank. Nitrates are testing as high as my test kit will go (160ppm). I am not sure on my weekly growth as I haven't tested in a while, I admittedly got lazy with a happy tank. I am not new to the hobby - the tank is about 10 years old now and I haven't done a water change in a couple years. Nuisance algae died off and P04/N03 were doing good previously from vodka dosing alone. I do have some fuzzy purple looking algae (not sure on species), but not sure if that is an issue or not. I dose 19mL vodka a day (which seems like a lot to me). It wasn't until I lost a couple fish that I started doing a full panel and found this out. At that point I measured:

0 ammonia
0 nitrites
160+ppm nitrates
2.2 phosphates

So far what I have done is a 50gallon WC (16%). I blasted the rocks with a powerhead and did a gravel vac, and cleaned out the free debris in the sump.

Then I had a service come and do a ~160gallon water change (~50%), which cost me a pretty penny ($270). I tested a day later and nitrates still 160+ppm. I plan to test phosphates again, but I ran out of reagents for my hanna checker and need to order some more.

I have cut feedings down by half, plus have 2 less fish now producing nitrates.

I have a 40g reef tank in the same room that is thriving. I do 5gal weekly water changes there, all tests are good. It's just another beast entirely to do meaningful water changes on the 300gal. Looking for inspiration or advice.

I would like to do more massive water changes, but concerned with the cost and it possibly not solving my issue. I would also love to replace my sump, but it's barricaded in there pretty well by support beams so it would take some real surgery to get a new one in ($$). I might be able to cut two holes in the side walls, replace with a cabinet door, and then slide a brand new one with new plumbing. I wonder if I should reduce the vodka dosing or increase it. I have thought about buying an XPORT-NO3 brick (or 2) but I think it might be the same thing as the ceramic media I already have in the tank. Also read about a biodenitrator which sounds like it could help.

This weekend I plan to do another gravel vac (16% WC), do a full rinsing of my ceramic media, empty out my ATO reservoir and clean with vinegar (over time that thing always develops a thin slime, not sure what that is), and just clean out my dual carbon reactor for good measure. I will test again after all that and post an update.

I've also included some pics :)

20200910_182222.jpg 20200910_182247.jpg 20200910_182311.jpg 20200910_182327.jpg 20200910_195549.jpg
 
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nldemo

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Ah, one thing I left out was cleanup crew. I really don't have much of one right now, just a few tiny snails. There was a serpent star that roamed around every now and then, but haven't seen him in a while.

I sort of stopped collecting clean up crews because they seem to either die off quickly or get eaten, either of which just results in higher nutrients in my tank. I will likely invest in a few urchins once I get nitrate levels back in check to clean off the algae. I imagine they eventually die as well, but they are large enough I can easily remove them. I hope this doesn't sound too insensitive, I actually think the buggers are super cool and would love to keep them alive. I just can't seem to for whatever reason.

If there was any other details I left out, just ask :)
 
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nldemo

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Did you try a new test kit? Might be a bad kit

I tested against my reef tank as a control, and took a sample in to the LFS to compare. Their results were the same (though they used the salifert kit and I have the API). My kit is definitely a few years old, so if they truly "expire" it would be expired by now. But the results seem accurate.
 

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Ah, one thing I left out was cleanup crew. I really don't have much of one right now, just a few tiny snails. There was a serpent star that roamed around every now and then, but haven't seen him in a while.

I sort of stopped collecting clean up crews because they seem to either die off quickly or get eaten, either of which just results in higher nutrients in my tank. I will likely invest in a few urchins once I get nitrate levels back in check to clean off the algae. I imagine they eventually die as well, but they are large enough I can easily remove them. I hope this doesn't sound too insensitive, I actually think the buggers are super cool and would love to keep them alive. I just can't seem to for whatever reason.

If there was any other details I left out, just ask :)
Urchins will eat nori fwiw. Have you considered upgrading the skimmer? That could be a good piece of equipment for nutrient export and with that size tank the upfront cost would be equal to a few wc.
 
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nldemo

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I have an octa 205i skimz internal skimmer. Supposedly it's rated for up to 500gallons, so I believe it is already oversized for my tank. I do have a difficult time dialing it in to where it needs to be though. Some days, not enough.. other days it's overflowing. Water level remains the same. I have the same issues with my Vertex skimmer in my reef tank, so maybe it's just the internal style that is the issue.
 

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Maybe try some dr tims waste away? You could also give biopellets a shot. Do you have any room for a refugium?
 

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Hello!

I am battling a nitrate issue in my 300 gallon fish only tank. Nitrates are testing as high as my test kit will go (160ppm). I am not sure on my weekly growth as I haven't tested in a while, I admittedly got lazy with a happy tank. I am not new to the hobby - the tank is about 10 years old now and I haven't done a water change in a couple years. Nuisance algae died off and P04/N03 were doing good previously from vodka dosing alone. I do have some fuzzy purple looking algae (not sure on species), but not sure if that is an issue or not. I dose 19mL vodka a day (which seems like a lot to me). It wasn't until I lost a couple fish that I started doing a full panel and found this out. At that point I measured:

0 ammonia
0 nitrites
160+ppm nitrates
2.2 phosphates

So far what I have done is a 50gallon WC (16%). I blasted the rocks with a powerhead and did a gravel vac, and cleaned out the free debris in the sump.

Then I had a service come and do a ~160gallon water change (~50%), which cost me a pretty penny ($270). I tested a day later and nitrates still 160+ppm. I plan to test phosphates again, but I ran out of reagents for my hanna checker and need to order some more.

I have cut feedings down by half, plus have 2 less fish now producing nitrates.

I have a 40g reef tank in the same room that is thriving. I do 5gal weekly water changes there, all tests are good. It's just another beast entirely to do meaningful water changes on the 300gal. Looking for inspiration or advice.

I would like to do more massive water changes, but concerned with the cost and it possibly not solving my issue. I would also love to replace my sump, but it's barricaded in there pretty well by support beams so it would take some real surgery to get a new one in ($$). I might be able to cut two holes in the side walls, replace with a cabinet door, and then slide a brand new one with new plumbing. I wonder if I should reduce the vodka dosing or increase it. I have thought about buying an XPORT-NO3 brick (or 2) but I think it might be the same thing as the ceramic media I already have in the tank. Also read about a biodenitrator which sounds like it could help.

This weekend I plan to do another gravel vac (16% WC), do a full rinsing of my ceramic media, empty out my ATO reservoir and clean with vinegar (over time that thing always develops a thin slime, not sure what that is), and just clean out my dual carbon reactor for good measure. I will test again after all that and post an update.

I've also included some pics :)

20200910_182222.jpg 20200910_182247.jpg 20200910_182311.jpg 20200910_182327.jpg 20200910_195549.jpg

Your system needs higher nitrogen export. 19 mL of vodka is likely too low for the bioload. I was just reading about the effectiveness of sulfur denitrators. Growing macro algae in a sump could help. Water changes won’t work well because the big fish need to eat and the system is probably generating many ppn NO3 per day.

I have a similar situation. I feed a big fish in a 85 gallon system and dose vinegar, about 1 mL per gallon per day with a doser over the entire day. That is approximately equivalent to 1/8 mL per gallon vodka. This is at the point where a white slime of bacteria growth accumulates on the glass every few days.
 

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Had the same issues battling nitrates in a tank with big messy puffers. I always maxed out every test kit. Refugium, biopellets, and nopox didn't have any substantial impact on this tank. A Sulfur denitrator (aka biodenitrator) will take care of this and will give you near zero nitrates.

You will then have to spend some time with tuning alk/ph once it kicks in however since its fowlr its less critical.
 

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I totally agree with Unreefer. I got the seapora sulfur denitrator For my 560 gallon and it destroyed my nitrates in no time. I bought it a few years ago for this tank that had 60-80 nitrates and In no time zeroed them out. I sold the tank but out of a weird twist of fate ended up getting it back a few months ago and the rock I used was leaching nitrates like crazy. Dark red using API. So I set it up a little better than a week ago and it’s taking about 150 gallons a day now from 40 ish to 0. They do mess with ph and alk though is there only pitfall. Start off with a drop per second coming out and test until it reads 0 then keep increasing the flow ever so slightly each day testing the flow to make sure it’s 0. Mine fills a beer bottle in 50 seconds now lol. Of nitrate free water continuously. Won’t take long to zero them out this time around either...
 
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nldemo

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They do mess with ph and alk though is there only pitfall.

I wouldn't be too worried about alk dropping as it is FOWLR, but pH could be a concern. What do you do to counter act the pH drop? Just add soda ash back in?
 
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nldemo

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Maybe try some dr tims waste away? You could also give biopellets a shot. Do you have any room for a refugium?

I would love to add a fuge, but the wet/dry sump just isn't really designed for it. I got this tank used (which saved me over 10k), but I've always hated the sump design. I would love to replace the wet/dry with a mechanical sock filter and a fuge.

I have never tried biopellets, but I do have the dual reactor which I'm only using for activated carbon right now. Any thoughts on replacing the carbon in there with biopellets? Would I want to stop or phase out my vodka dosing while letting that work? They seem to attack the problem in the same way.

Dr Tim's sounds like it might help, but so does every other bacteria in a bottle. I don't want to overdo it with those just yet :)
 

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I wonder if I should reduce the vodka dosing or increase it.

As long as:
the skimmer is pulling the bacteria out,
and as long as you don't have white slime on the glass,
and as long as your other parameters don't suffer,

You can increase the vodka.
 
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nldemo

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thanks. right now my concern is trying to change too many things at once. Of course, cleaning won't affect anything negatively so I can always do a bit more of that.
 

AC1211

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Hello!

I am battling a nitrate issue in my 300 gallon fish only tank. Nitrates are testing as high as my test kit will go (160ppm). I am not sure on my weekly growth as I haven't tested in a while, I admittedly got lazy with a happy tank. I am not new to the hobby - the tank is about 10 years old now and I haven't done a water change in a couple years. Nuisance algae died off and P04/N03 were doing good previously from vodka dosing alone. I do have some fuzzy purple looking algae (not sure on species), but not sure if that is an issue or not. I dose 19mL vodka a day (which seems like a lot to me). It wasn't until I lost a couple fish that I started doing a full panel and found this out. At that point I measured:

0 ammonia
0 nitrites
160+ppm nitrates
2.2 phosphates

So far what I have done is a 50gallon WC (16%). I blasted the rocks with a powerhead and did a gravel vac, and cleaned out the free debris in the sump.

Then I had a service come and do a ~160gallon water change (~50%), which cost me a pretty penny ($270). I tested a day later and nitrates still 160+ppm. I plan to test phosphates again, but I ran out of reagents for my hanna checker and need to order some more.

I have cut feedings down by half, plus have 2 less fish now producing nitrates.

I have a 40g reef tank in the same room that is thriving. I do 5gal weekly water changes there, all tests are good. It's just another beast entirely to do meaningful water changes on the 300gal. Looking for inspiration or advice.

I would like to do more massive water changes, but concerned with the cost and it possibly not solving my issue. I would also love to replace my sump, but it's barricaded in there pretty well by support beams so it would take some real surgery to get a new one in ($$). I might be able to cut two holes in the side walls, replace with a cabinet door, and then slide a brand new one with new plumbing. I wonder if I should reduce the vodka dosing or increase it. I have thought about buying an XPORT-NO3 brick (or 2) but I think it might be the same thing as the ceramic media I already have in the tank. Also read about a biodenitrator which sounds like it could help.

This weekend I plan to do another gravel vac (16% WC), do a full rinsing of my ceramic media, empty out my ATO reservoir and clean with vinegar (over time that thing always develops a thin slime, not sure what that is), and just clean out my dual carbon reactor for good measure. I will test again after all that and post an update.

I've also included some pics :)

20200910_182222.jpg 20200910_182247.jpg 20200910_182311.jpg 20200910_182327.jpg 20200910_195549.jpg
My honest response is don't worry too much about nitrates in a fish only. We don't like to admit it but it takes nitrates over 700 ppm to affect delicate fish. My freshwater tank hit 970ppm at one point on a commercial test kit. Guess what all fish were fine and some were breeding. Saltwater fish have been easy for me as well. Of course now my freshwater tank is back to under 200ppm now and I bring it down to 40ppm before adding small fish as small fsh cannot take large changes. Honestly a small 5g water a week for a few weeks first to get fish used to water changes then proceed with increasing ones as needed.
 
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nldemo

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In my case a 5gal change would do nothing, as the tank is 300g :)

I do agree that fish can be fine under high nitrates, but in the long term impact on their health is unknown. Most would believe it is not so great. Some have compared it to drinking and our liver - a little every day is fine, but too much all the time and your liver goes.

Personally I am fine with running something like 40nitrates since I am not keeping corals in this tank, but I want it to be at least lower than 100 so I can test and track it.
 
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nldemo

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You could also give biopellets a shot.

Has anyone tried biopellets vs Seachem De-Nitrate Filter Media ? Is one more effective than the other? Biopellets seems to be in line with what I'm trying to do already via vodka dosing, so maybe the seachem stuff would work better for me..?
 

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Has anyone tried biopellets vs Seachem De-Nitrate Filter Media ? Is one more effective than the other? Biopellets seems to be in line with what I'm trying to do already via vodka dosing, so maybe the seachem stuff would work better for me..?

Denitrate or matrix probably won't be a end all solution. The reason why I was thinking biopellets is that you could seed them with some dr tims waste away, which supposedly gets it to go to work immediately.
 

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I would love to add a fuge, but the wet/dry sump just isn't really designed for it. I got this tank used (which saved me over 10k), but I've always hated the sump design. I would love to replace the wet/dry with a mechanical sock filter and a fuge.

I have never tried biopellets, but I do have the dual reactor which I'm only using for activated carbon right now. Any thoughts on replacing the carbon in there with biopellets? Would I want to stop or phase out my vodka dosing while letting that work? They seem to attack the problem in the same way.

Dr Tim's sounds like it might help, but so does every other bacteria in a bottle. I don't want to overdo it with those just yet :)


A dual reactor isn't recommended for biopellets. Biopellets do work similar to vodka, but I am curious if it may work better.


As for the sump, have you ever thought of taking the sump offline and switching it out?


Alternatively, you could make or buy an algae reactor.
 
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nldemo

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A dual reactor isn't recommended for biopellets. Biopellets do work similar to vodka, but I am curious if it may work better.

As for the sump, have you ever thought of taking the sump offline and switching it out?

Alternatively, you could make or buy an algae reactor.

What would be the issue with running biopellets in the dual reactor?

Yes, and I think I mentioned this earlier, but the issue is the sump tank is boxed in by two support braces. So we'd have to cut out two large squares in the side walls and then put a new cabinet door on the far edge of the stand. Then I could potentially slide that one out and a new one in. Possible, but a good deal of effort and $.

I have been interested in the algae reactors such as these (reactors) but I'm not sure how well they work and for what tank size. Since I can't currently fit a fuge, this could be the next best thing. But since nitrates are my only issue, maybe all I really need is a sulfur denitrator...
 
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