Can't seem to keep nitrates down

[drawman]

I've been trying to solve my high nitrate issue in my 60 gallon rimless tank for several months. I have been keeping reef tanks for a long time so I'm almost embarrassed by the issue as I feel like I should have solved it by now. This tank I mostly maintain on the weekends as I work in another city during the week. My wife does most of the feeding during the week when I'm gone. Up until this Spring I wasn't doing as much as I should have been with maintenance other than weekly/biweekly 10-15 gallon water changes. I had red cyano issues as well (mostly on the sandbed) which I have mostly cured other than a few patches on the rock.

First off here is my equipment list:
Tank: 60 gallon Marineland Rimless Cube
Sump: 15 gallon DIY
Flow: Ecotech MP40QD and Maxspect Gyre 130
Skimmer: Vertex Omega 130 with air intake mod to reduce air
RO/DI: BRS RO/DI Unit with well maintained prefilters and DI resin - 0ppm TDS

and my stocking list:
Medium Yellow Tang
Aiptasia Eating Filefish
Orchid Dottyback
One peppermint shrimp and several mixed snails

My wife and I feed Rod's Food once/day probably about the size of a dime to a nickel.

I've been using Aquaforest probiotic salt and -NP Pro for many months but really got on track with dosing and filtration this past Spring.

Things I have done thus far:
1. In April 2016 I added 1 gallon of SeaChem Matrix to the sump in containers to provide surface area for Aquaforest Pro Bio S bacteria for denitrification. I have one large piece of live rock in the tank so I was likely lacking there.
2. I automated dosing of the -NP Pro (carbon dosing) on 7/11/16 via a BRS dosing pump that doses 2x daily for roughly a total of 11mL (per their recommended dosing). Beforehand, my wife and I were manually dosing and were probably not as consistent and we should've been. I still dose the Pro Bio S but mostly on the weekends so 2/3 times/week.
3. A few weeks ago I added the MaxSpect Gyre 130 which I think greatly improved the flow in this tank and hopefully is keeping detritus from settling. Just having the MP40QD was doing a terrible job by itself in this style of tank for me.
4. About a month ago I adjusted the mod on my Vertex 130 to really ramp down the air and I think that is helping quite a bit. I am getting about 1-1.5" of dark skimmate/week - most of the chunks are left in the collection cup's neck and removed.

This past Spring/Summer I was getting a fairly consistent Nitrate reading of 50ppm from a Salifert test kit. Over the past 8 weeks or so I have been doing very large water changes (started with 20 gallons then ramped it up to 40 gallons) every week including siphoning of the sandbed. I was able to get my Nitrate readings down to under 10ppm before going to Germany at the end of August. To my surprise, my reading was right back up to 50ppm the week after I got back. I guess the tank sitter could have been feeding a lot more than instructed but that seems a little high. I've been keeping up with my large water changes since. Last weekend I was testing at 10ppm and this weekend it was up between 10 and 25ppm from the Salifert test so I'm still gradually rising.

I figure I have a few options going forward if things don't level out/improve:
1. Change out my protein skimmer. I've thought hard about going to a Deltec 1351.
2. Remove/replace my sandbed
3. Increase my carbon dosing amount
4. Add some additional biofiltration in the form of chaeto/ATS to reduce nutrients

Thanks for reading my long rant and sorry if I left anything out. I'm getting a little tired of doing such large water changes and want to get to a point where I can keep my nitrates under 10ppm. I guess this is my cry for help so all opinions are welcome.

 

[bif24701]

Have you tried increasing the carbon dosing? A little every week. I've experimented with large one time over doses of vinegar with high nitrates with great success.

 

[drawman]

Have you tried increasing the carbon dosing? A little every week. I've experimented with large one time over doses of vinegar with high nitrates with great success.

I haven't tried it but I've sure thought about it. It was one of my last points in my first post. I guess I'm debating if it should be my best step going forward...

 

[71xlch]

I was sitting at 50ppm nitrate. Followed the guide online and around 6 weeks the reduction was dramatic. Now at 8 weeks and a maintenance dose it hovers at 0-5ppm. Just program my doser and check weekly now.

 

[drawman]

I was sitting at 50ppm nitrate. Followed the guide online and around 6 weeks the reduction was dramatic. Now at 8 weeks and a maintenance dose it hovers at 0-5ppm. Just program my doser and check weekly now.

How much is your maintenance dose and how big is your aquarium out of curiosity? I guess I had hoped that dosing 11mL/day would have knocked the nitrates down but maybe I do need more.

 

[jlanger]

I have been going through a similar experience this summer as well; high nitrates for a long-time hobbyist.
I've done the carbon dosing bit (NO-POX) with limited results.
I've added some ceramic media blocks for added biological filtration.
I spent a month doing 50% water changes to get my nitrates down from 40ppm to 4ppm; only to have them rise again when I went back to weekly 20% water changes.
I decided that I needed to find the source of my problem instead of investing time and money in fighting the problem.

So I ask you... Do you have a sand bed? And how old is it?

I ask because I had a shallow (1-½" to 2") fine-grained sand bed in my reef tank. I have nassarius snails, pistol shrimps with a goby and a leopard wrasse that keep the sand bed fairly mixed up, but the sand's grains were too fine to be vacuumed as they would get sucked out with the water. My thinking was that my sand bed became a sink for nutrients over the past three years. Over the last month or so, I removed the old sand bed and replaced it with the Special Grade reef sand; larger grain size that can be vacuumed.
This week marks the first week to see if replacing the sand bed had anything to do with the high nutrient levels. I still manually dose the NO-POX and have the ceramic media blocks, so I'm hoping to see a drop in my nitrate levels over the next couple of months doing my regular 20% weekly water changes; if the sand bed was the source of my nutrients.
I also have plans of adding an ATS to my filtration regimen.
One way or another, I'll get my nutrient levels within an acceptable range!

So I would recommend finding the source for your high nutrient levels first.
Fighting them may help, but how long can you fight?

 

[bif24701]

Over does the **** out of that carbon, just saying.

 

[drawman]

I have been going through a similar experience this summer as well; high nitrates for a long-time hobbyist.
I've done the carbon dosing bit (NO-POX) with limited results.
I've added some ceramic media blocks for added biological filtration.
I spent a month doing 50% water changes to get my nitrates down from 40ppm to 4ppm; only to have them rise again when I went back to weekly 20% water changes.
I decided that I needed to find the source of my problem instead of investing time and money in fighting the problem.

So I ask you... Do you have a sand bed? And how old is it?

I ask because I had a shallow (1-½" to 2") fine-grained sand bed in my reef tank. I have nassarius snails, pistol shrimps with a goby and a leopard wrasse that keep the sand bed fairly mixed up, but the sand's grains were too fine to be vacuumed as they would get sucked out with the water. My thinking was that my sand bed became a sink for nutrients over the past three years. Over the last month or so, I removed the old sand bed and replaced it with the Special Grade reef sand; larger grain size that can be vacuumed.
This week marks the first week to see if replacing the sand bed had anything to do with the high nutrient levels. I still manually dose the NO-POX and have the ceramic media blocks, so I'm hoping to see a drop in my nitrate levels over the next couple of months doing my regular 20% weekly water changes; if the sand bed was the source of my nutrients.
I also have plans of adding an ATS to my filtration regimen.
One way or another, I'll get my nutrient levels within an acceptable range!

So I would recommend finding the source for your high nutrient levels first.
Fighting them may help, but how long can you fight?

Thanks for the detailed response Jason. I've followed your thread and I know my situation has mirrored yours. I've thought that my sandbed could be the culprit and I've tried to siphon the hell out of it which has cleaned it up considerably. The sand bed is a solid 2 years old and depth is at about 2" or less. It is Fiji Pink sand so it is relatively fine as well. Lack of flow over those two years may have turned it into a nutrient sink. I guess at this point I see no harm in removing it and if nitrates stabilize then I can add a larger grain with a somewhat shallower depth.

I am totally with you fighting it weekly is wearing me out!

Over does the **** out of that carbon, just saying.

This definitely may not be a bad call either. I'll try to gradually increase it I'm just not sure what my upper limit is with the aquaforest source of carbon. I would assume if I gradually increase it and continue to test then I won't run into problems.

 

[bif24701]

Wouldn't hurt anything to double or even triple that does, IMHO.

 

[drawman]

My plan going forward will be to remove the sand bed (a little at a time while doing weekly water changes) and steadily increase the -NP Pro dosage (by 1mL/week). I will try to document my progress here and I'm keeping my fingers crossed!

Just increased daily dose of -NP from 11mL to 12mL

 

[jlanger]

Sounds like a good plan to me.
I just tested my nitrates this morning.... 4ppm!

 

[SaleenCB]

I feel your pain...can be very frustrating. I initially started with bio-pellets and ceramic media blocks (I'm not convinced these blocks work for nitrate reduction...but I am convinced they aid in the battle against ammonia and nitrite.) I became discouraged with the bio-pellets and after stopping them, I switched over to NoPox and had awesome results.

However, I am also a fanatic about the cleanliness of my tank and with any carbon dosing you will start to see bacterial growth after a while and that drove me nuts. My Nitrates went to Zero, which was awesome. I have now stopped dosing and have an elevation at 4 PPM. I also run carbon/gfo and I also think additional CUC that consists of sand sifting snails (Nassarius) and a diamond watchman goby to help keep bed clean helps as well.

Another point of interest is Rod's food...I like it as well and still use it occasionally but when I did a comparative analysis of Rod's vs LRS, I noticed that the LRS was much cleaner...just some food for thought

Lately, I have been looking at the addition of Algae Turf Scrubbers but haven't pulled the trigger yet. My goal is to try to get away from any chemical additives if possible.

 

[bif24701]

My plan going forward will be to remove the sand bed (a little at a time while doing weekly water changes) and steadily increase the -NP Pro dosage (by 1mL/week). I will try to document my progress here and I'm keeping my fingers crossed!

Just increased daily dose of -NP from 11mL to 12mL

In my very very humble opinion, 11ml-12ml is way to conservative. Try 24ml, just for today.

 

[71xlch]

Sorry was out for the weekend just responding now. I'm at 18ml a day for 50 gallons total water volume. I hit 33ml and wouldnt drop. Went to 40ml for a week and hit zero and then I backed off to 30 for a week then 22 and now 18.

 

[Brew12]

My plan going forward will be to remove the sand bed (a little at a time while doing weekly water changes) and steadily increase the -NP Pro dosage (by 1mL/week). I will try to document my progress here and I'm keeping my fingers crossed!

Just increased daily dose of -NP from 11mL to 12mL

Any chance it is a problem with your test kit?

 

[bif24701]

Oh yea, be sure to shake the **** out of those API nitrate tests

 

[scfurse77]

I switched over to NoPox and had awesome results.

I also use NOPOX in a smaller tank. It's the only thing that seems to work for me.

 

[becks]

I reduced my nitrates by building a homemade nitrate reactor, I used two spaghetti containers, I drilled a hole at the bottom and the top of both containers and used epoxy to secure the plastic fittings in the tube with silicone on the outside part of the fitting. I then purchased a small £5 adjustable pump with a max flow of 200lph. I connected this to the bottom of one of the containers, then the top fitting was connected to the bottom fitting of the second container and the top fitting had a hose exiting near the baffle of the sump. I filled the containers with 3litres of seachem de-nitrate and my nitrates exiting the reactor is 0ppm. each spaghetti container can hold 1.7l. my tank is 150g.

This is the spaghetti container I used, minus the spaghetti;

Seachem De-Nitrate does not need to be replaced, it just needs rinsing with salt water every now and then, but its important to have flow less than 200lph, I had to reduce mine down to 125lph, I could experiment and start rising but I'm happy where its at.

 

[iiluisii]

You skimmer is on the small side. I my 60 gallon I had a vertex omega 200i. The smallest I would run on your tank is the 150

 

[jsker]

I to was have an issue with nitrates 50+, I was dosing NP pro with very little results, by its self. Setup a reactor with a 1/4 dose of bio pellets at a slow tumble and in two weeks when the bactria kick in my nitrates dropped to 4 ppm red sea test. Last week I started to dose Pro bio S along with NP pro after learn both are supposed to be used together to reduce nutrients. I do have a sand bed and vacuum the sand periodically with water changes this also help export the nutrients. There is a new product coming out Life Bio Fil that might be the answer to exporting nutrients.