Starved for Nitrates?

[rottenjohnny]

I'll trade you my nitrates for some clean water! I have never been able to get my nitrates below 20ppm even after 40% water change two weeks in a row. They just sit at 20-30ppm. Any suggestions on lowering them. I have a 100gal with sump, live rock and 2" of figi pink sand. Maybe a fuge?
Thanks

 

[yeame]

i would just ad some TLC or another type of bacteria to add nitrates safely

 

[3D-Reef]

MarkD40,
If the main goal is to grow plants(refugium),then graveyardworm's link will provide the best way to go.If No3 is at o.oppm then additions of Kno3 would be needed.
If you increase the food input,then the bac' have to convert it to ammonium,(source for green hair alge) to nitrite,(source for red hair alge) then to nitrate for the macro's and plants.

If your trate's are already at nondetectable IMO I don't think vodka would work for you in this instance.
Clay

 

[G-money]

Agreed - potassium nitrate will add nitrate pretty safely. I wouldn't mess with too much ammonia...

I doubt that bacteria would be outcompeted by any algae on the planet. Just a hunch.

You can ensure the algae gets nutrients by putting it somewhere that detritus would be able to accumulate in and around it. A low flow area of the sump is often good, but that assumes your detritus doesn't go right to the bottom of your tank - and sit there.

Personally, I would just feed the tank more.

 

[Samala]

I would definitely not add ammonia. Algae candy that stuff.

Trouble with over feeding is that it tends to increase the P content of your water just as it increases the N.. and the plants/macros need more N than P.

But I digress.. thats fairly well covered in that thread David linked you too. Still, the Coral mag articles are very good for this topic as far as nutrient limited aquariums.

>Sarah

 

[Humuhumunuku]

what people forget is that their huge lighting set ups are there for a reason. Although a small amount of organic nutrients are required, light is the primary source of energy, and therefore growth for plants and corals alike. One of the primary reasons a refugium is added is to remove nitrates...seems kind of counter productive to add nitrates so you can have a refugium.

 

[3D-Reef]

MarkD40,
Have You been invited/E-mailed about Sundays reef meeting?If You show up We can discuss a theory I've been working on,only thing is,if You can't sleep afterwards...it ain't My fault.
Clay

 

[graveyardworm]

<a href=showthread.php?s=&postid=7214942#post7214942 target=_blank>Originally posted</a> by Humuhumunuku
One of the primary reasons a refugium is added is to remove nitrates...seems kind of counter productive to add nitrates so you can have a refugium.

It wouldnt necessarily be counterproductive if your problem was high phosphates. Generally phosphates are what drive nuisance alga, and the uptake of NO3 and PO4 are not the same, the ratio is something like 16:1, but does vary depending on species and what other nutrients may be available. So for a macro to use 1 PO4 molecule it needs 16 NO3 molecules So even with macro for nutrient export if it doesnt have enough NO3 your PO4 and nuisance micro could easily increase. Here's a couple links.

http://www.reefcentral.com/forums/showthread.php?s=&threadid=611702

http://www.reefcentral.com/forums/showthread.php?s=&threadid=718016

http://reefcentral.com/forums/showthread.php?s=&threadid=675131&highlight=ratio

 

[MCsaxmaster]

Adding an alga shouldn't harm the bacterial flora in any perceptible way. If you want the algae to grow faster the easisest thing to do (like mentioned) is probably feed the fish a little heavier.

The 16:1 N ratio (Redfield's ratio) applies to phytoplankters, not to attached algae. Benthic algae tend to average nearer 30:1. The optimal stoichiometry for algae, however, can range from 8:1-80:1 depending on the species and other conditions. The 16:1 Redfield measured and 30:1 Atkinson measured are averages over many species and many conditions and are meant to be interpreted as such.

As for adding N to get algae growth being counterproductive, I'd strongly disagree. Growing algae is a great way to take up N and P. If there is too much dissolved N and P the algae can help lower it, achieving the goal. If the N and P are already low in the water and the algal growth is also low, adding some grows the algae faster without deteriorating water quality, achieving the goal.

Chris

 

[Fredfish]

I have found that dosing nitrate as neeced (even phosphate once) drives macro algae growth which in turn inhibits micro algae growth.

I had recently let my tank go a little and the macro was stagnating. Even had some grape caulerpa go sexual. I was seeing elevated growth of cyano and diatoms. Two days after dosing some nitrate the macros perked up and 80-90% of the micro algae died.

Don't get me wrong, nitrate dosing is not a miracle cure. I do still have some cyano in the tank, just not very much. I think you also need to be careful not to dose to heavily or you will end up with enough to grow all types of algae at once. I usually target 2.5mg/l

Fred

 

[wahwoo]

The macro is covered in bateria just like all your rock and equipment. macro has excellant surface area for it.

 

[Samala]

Chris I'm glad you mentioned that they are wide averages in uptake ratios.. I was finding for a long time that a few planted tanks where echoing those ratios.. about 16-18:1 N which I thought was interesting given some academic work with phytoplankton and knowing of the Redfield ratio. Some of my test tanks still average (as whole systems of effective DSBs, plants, bits of microalgae populations, nutrient inputs from inverts, etc) right near Redfield but I definitely have other systems that vary widely from this.. an all Caulerpa tank for example is averaging more like 65:1 (I'm soooo tired of adding N to that tank!!), one with only Ulva is about 20:1 or so, and two seagrass setups are going full tilt at about 24:1.

So, like you're leaning, I'm less inclined to encourage people to be precisley adding 16 N's for every 1 extra P they've got, but its a good baseline to simply recognize that the algaes (micro or macro) and plants need much more N than P.

This has really turned into a nice thread.

>Sarah