How long for Nitrates to go down?

[jm82792]

Cheato does wonders:D

Really though add some cheato after the cycle and you should have help lowering the nitrates.

[sarah_nick]

Update:

 

I haven't added chaeto yet as I'm trying to find somewhere that sells it in the UK. I've found some on ebay but am concerned that it might be dead when it arrives as it's not ebay shops - it's just individual people.

 

I've kept up with the water changes, and still only have the same 5 turbo snails and the same 3 kilo's of live rock. Nothing else has been added.

 

The diatom bloom seems to be returning though, lots of brown algae on the sand and rocks now, much more than there was before. The tank is now 6 weeks old - do you think my nitrates may go on their own following this?

 

Thanks

[supraeli]

I'm of the opinion that stocking should be slow, meaning months or weeks for cured rock, and that the nitrates will be thus be low before heavily stocking, which helps avoid nuisance algae blooms. Zero nitrates shouldn't be the objective, but instead less than 10 ppm is an acceptable range, as stated by Prop. Yes, the wait for low nitrates may be months (surely not a year), but it does happen. Denitrification probably plays a role for established tanks of many members to survive without water changes for many weeks. I remember even Chris Marks going with only top offs for at least a month. However, hankb is right that the zooxanthellae and other algae play a large role in reducing nitrates on their own.

 

This article is related to the subject under myth 15 from borneman, who could be considered "overly conservative":

http://www.reefkeeping.com/issues/2004-01/eb/index.php

 

i dont mean to questions EVERYTHING you say haha, but i do have a question about zooxanthellae consumption of nitrogenous compounds. from what i know, the symbiotic relationship between the endosymbionts and the corals are related to the exchange of energy. from what i recall, the zooxanthellae consume the anthozoan waste products of nitrogen and phosphate. thus, it would be reasonable to say that healthy corals should theoretically produce more waste products than the zooxanthellae would consume, thereby disabling them from processing any free nitrogenous compounds from the surrounding system?

 

so while i agree that the zooxanthellae should decrease the amount of waste produced by corals, im not sure that they have the capability of decreasing free nitrogenous compounds in the water?

 

other than that point, i completely agree with everything you said - i am also a strong advocate of long cycling times to establish biodiversity before introducing more complex organisms. and after reading the articles that you have provided, i concur with the concept that denitrification will become established over extended periods of time as it is true that older tanks can go longer without water changes.

[supraeli]

Update:

 

I haven't added chaeto yet as I'm trying to find somewhere that sells it in the UK. I've found some on ebay but am concerned that it might be dead when it arrives as it's not ebay shops - it's just individual people.

 

I've kept up with the water changes, and still only have the same 5 turbo snails and the same 3 kilo's of live rock. Nothing else has been added.

 

The diatom bloom seems to be returning though, lots of brown algae on the sand and rocks now, much more than there was before. The tank is now 6 weeks old - do you think my nitrates may go on their own following this?

 

Thanks

 

chaeto is relatively hardy - it should ship quite well, and as mentioned previously, it really does wonders for reducing dissolved organics.

 

diatom bloom is strange though - im wondering whether the water you are using may contain too much silicates? what kind of top off water do you use?

[bdare]

If the tank is only 6 weeks old it's VERY normal to have a diatom bloom during that time frame. I would not worry about it one bit.

[supraeli]

If the tank is only 6 weeks old it's VERY normal to have a diatom bloom during that time frame. I would not worry about it one bit.

 

oh its 6 weeks, not 6 months haha i misread.

 

what he said.

[sarah_nick]

Thanks.

 

I'll go for the ebay option and get some chaeto from there.

 

Fingers crossed nitrates will reduce after my second diatom bloom with help from chaeto then! I'll post some pics shortly!!

[lakshwadeep]

i dont mean to questions EVERYTHING you say haha, but i do have a question about zooxanthellae consumption of nitrogenous compounds. from what i know, the symbiotic relationship between the endosymbionts and the corals are related to the exchange of energy. from what i recall, the zooxanthellae consume the anthozoan waste products of nitrogen and phosphate. thus, it would be reasonable to say that healthy corals should theoretically produce more waste products than the zooxanthellae would consume, thereby disabling them from processing any free nitrogenous compounds from the surrounding system?

 

so while i agree that the zooxanthellae should decrease the amount of waste produced by corals, im not sure that they have the capability of decreasing free nitrogenous compounds in the water?

 

other than that point, i completely agree with everything you said - i am also a strong advocate of long cycling times to establish biodiversity before introducing more complex organisms. and after reading the articles that you have provided, i concur with the concept that denitrification will become established over extended periods of time as it is true that older tanks can go longer without water changes.

 

One assumption in your argument is that the coral animals are getting enough nutrition to produce a lot of nitrates for their algae. However, the relatively sterile environment of a reef tank (with low stocking/feeding) means much of the available nutrients are quickly used up. I've even heard of some large tanks having to specifically dose a nitrate source because a little helps to increase the coral health. It mostly depends on the type of corals, and this article has a good chart that shows how some corals can be almost completely autotrophic:

http://reefkeeping.com/issues/2002-08/eb/index.php

A related article talks about food in reefs:

http://reefkeeping.com/issues/2002-07/eb/index.php

[supraeli]

One assumption in your argument is that the coral animals are getting enough nutrition to produce a lot of nitrates for their algae. However, the relatively sterile environment of a reef tank (with low stocking/feeding) means much of the available nutrients are quickly used up. I've even heard of some large tanks having to specifically dose a nitrate source because a little helps to increase the coral health. It mostly depends on the type of corals, and this article has a good chart that shows how some corals can be almost completely autotrophic:

http://reefkeeping.com/issues/2002-08/eb/index.php

A related article talks about food in reefs:

http://reefkeeping.com/issues/2002-07/eb/index.php

 

SOMEBODY like reefkeeping.com! haha

 

again, great reads, thanks for pointing the articles out for me. however, in the first article, eric specifically notes that -

 

"The zooxanthellae are then carefully controlled by their coral host by being subjected to nitrogen limitation. As mentioned in last month’s article, nitrogen levels in coral reef waters are typically extraordinarily low, with most being found as ammonia... By limiting nitrogen in the form of excretion products, the polyp keeps the zooxanthellae in the numbers and density that maximize photosynthetic efficiency for its own use."

 

thus, corals NATURALLY do not produce enough nitrogenous compounds for the zooxanthellae to reproduce rapidly in order to maintain a monopoly over the photosynthetic output from the algae. the article goes on to point out -

 

"If nitrogen was made readily available to the zooxanthellae (for example, if high levels were present in the water and the dissolved nitrogen “diffused” into the coral tissue), it could then be accessed by the algae without limitation by the polyp, and zooxanthellae could begin to grow and reproduce like a “phytoplankton culture.” In this case, the symbiosis becomes less advantageous to the coral, and it will expel some of the symbionts to try and re-establish maximal benefit from its algal partners."

 

therefore, one can assume that relatively moderate levels of nitrogenous compounds in the water would STILL not have access through the coral tissue to be utilized by the zooxanthellae. also, even if this were to occur, the coral would simply expel any excess growing algae back into the water column, thereby negating the effects of the nitrogen consumption.

 

so while i concur that macro algaes and many of the micro algae species in a reef tank contribute dramatically to lowering dissolved nitrate levels, i cannot see the zooxanthellae embedded in the coral flesh offering much assistance.

[HankB]

One assumption in your argument is that the coral animals are getting enough nutrition to produce a lot of nitrates for their algae. However, the relatively sterile environment of a reef tank (with low stocking/feeding) means much of the available nutrients are quickly used up. I've even heard of some large tanks having to specifically dose a nitrate source because a little helps to increase the coral health. It mostly depends on the type of corals, and this article has a good chart that shows how some corals can be almost completely autotrophic:

http://reefkeeping.com/issues/2002-08/eb/index.php

A related article talks about food in reefs:

http://reefkeeping.com/issues/2002-07/eb/index.php

 

Thanks for posting those links. Very interesting read!

 

I've always thought that since corals are (overall) mostly photosynthetic, they would use nitrates and phosphates from the water column. After reading the first article I;m not so sure. It seems that the corals can control nitrogen availability to the zooxanthellae and perhaps that includes restricting access to those compounds in the water column. It didn't see confirmation either way in the first article.

 

I wonder if feeding the corals and presumably causing them to produce additional nitrogenous waste affects that. I always thought that feeding introduced additional nitrogen and phosphorous products to the tank by stuff that the corals missed, but it seems that they could be producing waste themselves. Certainly the non-photosynthetic corals must be doing that.

 

thanks,

hank