Persistent higher nitrates in a fallow system. Browning SPS frag.

[kerbfish]

My reef tank has been fallow (no fish) for 6 weeks (due to velvet outbreak).

I thought now would be a good time to set it up to get my nitrates down and add corals and try more SPS. After doing 2-3 20% water changes I noticed nitrates were not really budging. Salifert test kit was similar. I guessed nitrates were between 15 to 20 ppm based on color match.

I ordered a Hanna checker and to my surprise nitrates measured 8.9 ppm then a day or two later 10 ppm. I felt it was my test kit was off.

about 2 weeks later I decided to do about a 25% water change just for the hell of it. Remember I have no food input except maybe 1 cube a week for corals.

One day after Hanna checker read 18.5ppm.

I maybe have 10 hermit crabs, an emerald crab and Coral banded shrimp.

Only thing I can think of is I have had a lot of coralline algae die since I have been fallow and have had no skimmer running the entire time......but seriously I have done at least five 20-25% water changes in 6 weeks....so....

the tank was moved prior to all this which likely stressed my fish and LFS who moved my tank thoroughly cleaned the sand.....even though they were supposed to replace with all new.....

I also just switched to 6 stage RODI before this as well from running straight dechlorinated tap.

any other ideas on nitrate inputs? I always gravel vacuum every time I do a water change and I have vacuumed the sump. I am not running anything on the tank except filter socks and a bag of carbon at the moment.

I have had one SPS frag broke out at base and my light ate only set to 25% so not sure if. It’s nitrates. Calcium, alkalinity are good but alk in kinda high at 12.....I will attach pic of coral later today.

Thanks guys!

 

[Bfragale]

Hello there- I’m an not an expert but sounds like your beneficial bacteria population may have bees reduced with the sand cleaning and is not able to convert the nutrients. As things die off it’s probably releasing nutrients back into water. I think some people still feed fallow tanks a small amount of food to keep “feeding” the beneficial bacteria.
When you had fish- your biome would try to balance its self with regards to the bio load on the tank. When you remove fish your bio load went down- beneficial bacteria has no “food”.

maybe Through the move/clean and the reduction of fish waste - the benificial
Bacteria population had reduced.

again- I’m no expert lol- also learning as I go but this would be my first thought after reading your post.

I have read other posts that suggest adding bottlers bacteria to help boost the beneficial bacteria. Like microbacter7 or something similar.

one thing I noticed with my system. After I added gfo- I would see no3 rise. No matter what I did po4 lowered and no3 would rise.

I pulled the gfo offline and wala! Nitrites slowly started to decline. My thinking was- I was over striping po4 and the benificial bacteria’s need both no3 and po4 in balance to function properly. When I allowed po4 to come back up it gave the proper “food” to beneficial bacteria to boost its population and function properly.

sorry for rambling. I hope this makes sense. My only disclaimer is that I’m learning as I go and I would hate to give false advise- so take this into consideration but also continue your research.
Take care and happy reefing!

 

[Dkmoo]

are you running the skimmer now? i think that would be a start.

IMO I'm not sure how much of the beneficial bacteria is in the sand - according to some gurus on the forum like @brandon429 its not going to be a lot and the stratified waste is a much bigger source of waste so it's good that you have been vacuuming it out.

Other than dead coraline, Is your rock started from dry rock? that could be another source of NO3 as these rocks are very porous so can absorb waste since the beginning and is now leaching back to your system.

WCs can only take out as much NO3 as what the % says but it's not additive based on how many times you did it - ie, if your NO3 wsa at 10 and you do 20%, you will only remove 2, and if the tank raises by 2 in between each wc, then it'll always just hover between 8 to 10 until the source of the no3 exhausts.

Do you any algae growth? either nuisance/refugium? this would be a good source of absorbing No3.

It doesnt sound like you are adding much new nutrients so i would just let it run its course and keep up with WC. The current levels doesn't sound too bad. Is this a newer tank? I would hold off on getting any SPS until your tank matures more - esp right after a fallow period when the microfauna will likely need to readjust so will impact tank stability.

You can try some more hardier corals or softies - they usually prefer higher No3 than SPS anyway and can act as a good absorber of no3 as well.

 

[kerbfish]

My reef tank has been fallow (no fish) for 6 weeks (due to velvet outbreak).

I thought now would be a good time to set it up to get my nitrates down and add corals and try more SPS. After doing 2-3 20% water changes I noticed nitrates were not really budging. Salifert test kit was similar. I guessed nitrates were between 15 to 20 ppm based on color match.

I ordered a Hanna checker and to my surprise nitrates measured 8.9 ppm then a day or two later 10 ppm. I felt it was my test kit was off.

about 2 weeks later I decided to do about a 25% water change just for the hell of it. Remember I have no food input except maybe 1 cube a week for corals.

One day after Hanna checker read 18.5ppm.

I maybe have 10 hermit crabs, an emerald crab and Coral banded shrimp.

Only thing I can think of is I have had a lot of coralline algae die since I have been fallow and have had no skimmer running the entire time......but seriously I have done at least five 20-25% water changes in 6 weeks....so....

the tank was moved prior to all this which likely stressed my fish and LFS who moved my tank thoroughly cleaned the sand.....even though they were supposed to replace with all new.....

I also just switched to 6 stage RODI before this as well from running straight dechlorinated tap.

any other ideas on nitrate inputs? I always gravel vacuum every time I do a water change and I have vacuumed the sump. I am not running anything on the tank except filter socks and a bag of carbon at the moment.

I have had one SPS frag broke out at base and my light ate only set to 25% so not sure if. It’s nitrates. Calcium, alkalinity are good but alk in kinda high at 12.....I will attach pic of coral later today.

Thanks guys!

 

[kerbfish]

are you running the skimmer now? i think that would be a start.

IMO I'm not sure how much of the beneficial bacteria is in the sand - according to some gurus on the forum like @brandon429 its not going to be a lot and the stratified waste is a much bigger source of waste so it's good that you have been vacuuming it out.

Other than dead coraline, Is your rock started from dry rock? that could be another source of NO3 as these rocks are very porous so can absorb waste since the beginning and is now leaching back to your system.

WCs can only take out as much NO3 as what the % says but it's not additive based on how many times you did it - ie, if your NO3 wsa at 10 and you do 20%, you will only remove 2, and if the tank raises by 2 in between each wc, then it'll always just hover between 8 to 10 until the source of the no3 exhausts.

Do you any algae growth? either nuisance/refugium? this would be a good source of absorbing No3.

It doesnt sound like you are adding much new nutrients so i would just let it run its course and keep up with WC. The current levels doesn't sound too bad. Is this a newer tank? I would hold off on getting any SPS until your tank matures more - esp right after a fallow period when the microfauna will likely need to readjust so will impact tank stability.

You can try some more hardier corals or softies - they usually prefer higher No3 than SPS anyway and can act as a good absorber of no3 as well.

Thanks for the input. This tank was 2 years old and was covered with coralline. So should have had a ton of love bacteria. Rocks were never dried out....sand was rinsed in aquarium water so I presume a lot of bacteria was preserved.

truth is I am not having many issues at all with my nitrates at this level. I just find it interesting that they stay up with almost no inputs.

 

[Jekyl]

How long were you running tap water? There could be all kinds of issues associated with it.

 

[Dkmoo]

Thanks for the input. This tank was 2 years old and was covered with coralline. So should have had a ton of love bacteria. Rocks were never dried out....sand was rinsed in aquarium water so I presume a lot of bacteria was preserved.

truth is I am not having many issues at all with my nitrates at this level. I just find it interesting that they stay up with almost no inputs.

o, if the tank's that old - it may just be the opposite problem - ie, microfauna die off from lack of food. Since not everything will actually "eat" no3, much of that microfauna was probably depended on your fish poop and the leftover morsels of food when you were feeding daily. Either way, it should re-establish and stabilize itself to your pre-fallow levels once you add the fish back and keep up with what you were doing.

 

[Jekyl]

The bacteria that consumes nitrates shouldn't die from lack of food. They just go dormant more or less. I'd be worried that something else is causing die off in the tank.

 

[Dkmoo]

The bacteria that consumes nitrates shouldn't die from lack of food. They just go dormant more or less. I'd be worried that something else is causing die off in the tank.

i don't mean just bacteria - other parts of the microfauna - ie, worms, pods, etc that used to depend on the excess poop and such.. esp at levels that were previously maintained by daily feeding and daily pooping. unless all those guys can go on a 6 week hiberation too i'd expect some die off from those.

 

[kerbfish]

Hello there- I’m an not an expert but sounds like your beneficial bacteria population may have bees reduced with the sand cleaning and is not able to convert the nutrients. As things die off it’s probably releasing nutrients back into water. I think some people still feed fallow tanks a small amount of food to keep “feeding” the beneficial bacteria.
When you had fish- your biome would try to balance its self with regards to the bio load on the tank. When you remove fish your bio load went down- beneficial bacteria has no “food”.

maybe Through the move/clean and the reduction of fish waste - the benificial
Bacteria population had reduced.

again- I’m no expert lol- also learning as I go but this would be my first thought after reading your post.

I have read other posts that suggest adding bottlers bacteria to help boost the beneficial bacteria. Like microbacter7 or something similar.

one thing I noticed with my system. After I added gfo- I would see no3 rise. No matter what I did po4 lowered and no3 would rise.

I pulled the gfo offline and wala! Nitrites slowly started to decline. My thinking was- I was over striping po4 and the benificial bacteria’s need both no3 and po4 in balance to function properly. When I allowed po4 to come back up it gave the proper “food” to beneficial bacteria to boost its population and function properly.

sorry for rambling. I hope this makes sense. My only disclaimer is that I’m learning as I go and I would hate to give false advise- so take this into consideration but also continue your research.
Take care and happy reefing!

I think your reasoning is sound. I should know because I do water
Quality for a living! Haha. But aquariums are their own world and closed systems don’t have perfect cross over to natural systems. I almost never test PO4 because it is always pretty low.

There are so many variables changing at once both biologically and chemically I think it’s hard to pinpoint exact cause and effect. We never know unless we do a controlled experiment. But experience goes a long way in this hobby. And you have to try different things. I think I will add some bacteria anyway to help things along because I may add some export bricks before first fish arrive.

thanks!

 

[kerbfish]

Did the test again 7.6ppm....I was the error in this situation....