ULNS is not really L and far from UL
I’m annoyed when I see people boasting about their “ULNS” reef aquarium. Typically the “ULNS” crowd seem to think that their aquariums are at the very edge of complete dissolved inorganic nutrient elimination and that the corals they keep can barely cope with the underwater desert they’ve managed to create. All kinds of pseudoscientific theories are presented why corals in these systems seem to be so severely compromised that they can’t handle even the smallest variations in some water parameters like alkalinity. But why would corals be so stressed if you try to provide them more natural environment?
I think one of the problems is the definition of the term “Ultra Low Nutrient System.” It seems to me that this description really has nothing to do with the amount of nutrients in the system. Reading some of the forums where the term ULNS is most often used it looks like people understand ULNS as a system that uses some form of DOC dosing and/or zeolites to aid in nutrient export. Obviously that tells us nothing about how much dissolved nutrients there really are in the water. Some “ULNS experts” even insist that you should always have some measurable phosphates and nitrates in a “ULNS” reef aquarium. Talk about contradiction in terms!
However, the question remains: why are corals so stressed in ULNS systems that they suffer from chronic partial bleaching (“pastel” colors) and very quickly develop tissue necrosis after small and for most systems benign change in water chemistry? People like me have been using DOC dosing for more than 10 years and never had the kind of problems ULN systems have. Large number of people (including me) have maintained healthy reef aquariums with constant “zero” nutrients and high alkalinity for several years. You don’t have to be a rocket scientist to figure out that the term “ULNS”must mean something else than low nutrients and DOC dosing with or without zeolites.
So why not just be upfront about it and say you are using ZEOvit? It is very confusing when people describe their system as an “Ultra-Low Nutrient System” when it clearly isn’t. It is even more confusing when people claim that it is the low nutrients that cause the many problems so common with ZEOvit system. It is almost 100% certain that aquarium corals will never suffer from “too low” inorganic nutrients. Nutrition is a completely different story. Together with intentional heavy metal poisoning the lack of proper food is certainly a good candidate for many problems…
Truly L NS
What I would consider to be a low nutrient reef aquarium would be one with similar levels of dissolved inorganic nutrients that are commonly found at costal reefs. The “Ultra-Low” would be reserved for tanks with even more nutrient poor water, something like remote oceanic reefs.
Below is a recent study on water quality on several costal coral reefs in Australia. These values are a result of large number of measurements from several sites and I think these could be used as a guide to LNS aquarium. Many reefs have order of magnitude lower inorganic nutrient levels but getting aquarium water so clean might prove to be an impossible dream.
Note that the values are in ug/l (1 ug/l = 0.001 mg/l or 0.001 ppm).
Taking the annual mean values, a good candidate for a LNS reef aquarium would have 0.003 ppm PO4, 0.003 ppm nitrate and 0.2 ppm silicate. For phosphate, that’s 1/10th of detection limit of best PO4 test kits and 1/100th for NO3. Note that silicates are often too low in a typical reef aquarium!
Tatu
TDN mean total dissolved nitrogen which comes out at 76.10 inturn that would mean .076 nitrogen.
When reading my Salifert test kit I can’t even get 0.2 liquid is clear. Hopefully I am almost there.
Cheers
Kevin
Kevin,
True, but hobbyist test kits only measure inorganic nitrogen (ammonium,nitrite and nitrate). TDN contains both organic and inorganic forms (DIN+DON) and as you can see, almost all dissolved nitrogen is in organic form in reefs.
Actually, that’s how DON is typically determined: first you measure inorganic forms and then total. Organic portion is then simply calculated by subtracting DIN from TDN.
Tatu
So basically this means we have far more nutrients compared to natural sea water
There is also the Fauna marin system, but this is much different as it uses natural products to obtain results, a far better system.
Wow, so glad to hear a rational view of this. I am interested in your dosing silica. I was at a reef conference recently which got me thinking that despite our goals to eliminate diatom growth from the system, that diatoms might actually be doing quite a bit of the nutrient cycling, and that dosing silica might be an interesting way to bring down nitrates. What was your experience, what did you dose, and what’s your opinion of the whole mess?
Marc,
Thank you for the comment! I haven’t used FM system (other than invertebrate foods which, BTW, are excellent!).
Really, my criticism towards ZEOvit is mostly because of the intentional bleaching aspect of it and people blaming “low nutrients” for the problems they are having.
Christine,
Thank you for your kind words
I would recommend silicate dosing to everyone, just start slowly and let the diatom consumers build up. I’m using Sodium metasilicate dissolved in water. It should be available from online shops specializing in aquaculture although I now see that my long time favorite, Aquatic Eco-Systems Inc. doesn’t sell it anymore
My experience with silicate dosing has been overwhelmingly positive. You probably will need to clean the aquarium glasses more often so it is not for someone who wants the absolutely easiest setup available…
Hi Tatu,
good to see all of this on your website. This why I write articles about coral nutrition. The ZEOvit system is quite ridiculous and far too expensive. The reason why corals look so unnatural and are experiencing RTN when using ZEOvit is very likely due to starvation, in the sense that they are not acquiring sufficient plankton and detritus.
A fed coral is a happy coral.
Silicate is actually dosed to several zoo aquaria, to stimulate the growth of sponges.
Tim,
Very nice to hear from you!
Interesting that professionals use silicate. It would be a great subject for your next article at coralscience.org
Tatu
You grumpy old man. I did not know you had a blog. Nice to see you put things in a better perspective like the other old grumpy man often does
And thinks for you know what.
And I forgot there old buddy, for ultra Nitrate N-NO3 if interested
http://www.nitrate.com/sw-ntk2.htm
Hi Boomer!
Compared to you, I’m just a cheerful, young boy
Thanks for the NO3 test kit link, I’ll put it on top of my shopping list!
I ran zeo for over a year and I see exactly the point your trying to make!! I liked the results of zeo but modified the system a bit to make it more realistic and not dump loads of money into KZ’s pockets.
My question is this:
There are many examples of people having RTN and STN after a sudden alk spike occurs when maintaining very low nutrient levels (whether that be from the zeo process or other forms of achieving a very low nutrient level). The same reaction has been noted when a system, which is low in nutrients, (not just by the zeo process) is kept at an alk of 7-8dkh then the reefer tries to raise the alk to 9 or 10 dkh. I’ve done this myself and see necrosis as soon as the alk gets above 8 dkh (when doing this I raise alk very slowly over several days by increasing the alk 2 part dosing rate on my monitor – just want to clarify I’m not just dumping in a handful of soda ash). Any thoughts on why this tissue loss occurs?? This definately isn’t limited to just zeo systems.
Jeremy