Grumpy Old Reefer » Husbandry

NP-Biopellets, the story so far

Grumpy Old Reefer — Mon, 08 Feb 2010 18:21:47 +0000

It is often thought that one of the main reasons for our inability to keep many of the more delicate denizens of coral reefs is the lack of available (or acceptable) food. Back in spring 2009 I decided to see how far I could push feeding using a good quality skimmer (ATB Medium/1050A 1.5) and DOC dosing and still maintain reasonably good water quality. As expected, I eventually reached a rate of nutrient input that even my extreme DOC dosing couldn’t handle. At this point I was dosing 25 ml vodka plus 10 grams of sugar per day and yet I I still had measurable nitrate and phosphate. I started to notice many classical DOC dosing problems (corals loosing pigmentation, visible bacterial growths, restricted water flow in pipes and hoses etc). Thus I had only a couple of choices: I could either reduce feeding or add more and/or bigger technical equipment. For various reasons neither was attractive option for me.

After an ill-judged experiment with Tropic Marin BioActif (an experiment that left me with 25+ ppm NO3 and 1.0+ ppm PO4) I found an article (“Filter and suspension feeders” at coralscience.org) that mentioned a new form of filtration that made a lot of sense to me: a solid source of labile organic carbon that would release carbon only through enzymatic action of bacteria. This means two things: first of all, it makes overdosing pretty much impossible and secondly it avoids most of the problems that results from heavy use of DOC.

The old 2 liter setup. Pellets were quickly clogged with bacterial biomass.

I started out with only one liter of NP-reducing BioPellets (NPBs). Considering the “bioload” this was clearly too small amount for my tank but for once I wanted to be cautious. Seeing that nothing died and that the pellets were quickly colonized by bacteria (product was not available in stores at this time and there were no user reports) I added a second liter of NPBs. This was the recommended amount for the size of aquarium I have but considering my quite unorthodox feeding regime I didn’t stop the dissolved carbon dosing completely but cut it to half instead. With this combination of solid and dissolved organic carbon the nutrient levels stayed pretty much the same as they were with twice as high DOC dosing. So obviously the NBPs were working as advertised and I had reached my goal which was not to stop DOC dosing completely but to reduce it to more sensible level.

After a couple of months I still had some measurable nitrate (2.5 ppm) and phosphate (0.04 ppm) and I decided to really go “overboard” and ordered 3 more liters of NPBs. Since I didn’t have large enough “reactor” for this amount of NPBs I made a simple open top canister filter from an old 10 liter GAC container and a small 1000 l/h pump and placed the 5 liters of media in there. At the same time I stopped DOC dosing completely.

5 liters of NP-Biopellets in a 10 liter bucket. Using modest (1000 l/h) pump and large diameter container results in slow water velocity which seems to give best results in my case.

The results have been wonderful. It seems that the “critical mass” for my aquarium was around 5 liters of NPBs. The water stays crystal clear at all times and nitrates are finally dropping below 1 ppm. Using many commercial foods with excess phosphorous I still must use small amounts of GFO (before NPBs 2000 ml and now about 500 ml). I feed about 3-4 grams (dry weight) of pulverized invertebrate foods daily which is equal to about one 500 ml bottle of commercial liquid invertebrate food.

My NPBs used to get clogged pretty fast with thick bacterial growth but now, with twice as much surface area for them to colonize, the need to stir the media has diminished significantly. This might actually be a good indicator for sufficient amount of NPBs: if you find your media clogging very fast you might need more pellets to increase the usable surface area. Of course nitrate concentration is also a good indicator.

Comparison of costs of different filtration methods. Assuming 4 x 54W T5 lighting, 18 hrs/day. Bulb replacement every 9 months, 30% of NPBs yearly

I would recommend NPBs to all reef aquarists who are feeding their tank with invertebrate foods. Don’t be afraid to use more than recommended by the manufacturer. All tanks are different and manufacturers can only make general recommendations. Although the cost might seem high at first glance, NPBs are still a lot cheaper (and easier) than maintaining a large enough refugium to match the nutrient binding capacity of NPBs. Electricity and replacement bulbs aren’t cheap! There are also some competing products coming to market so I would expect the price to drop.

Coralscience.org is building a mesophotic reef system

Grumpy Old Reefer — Wed, 03 Feb 2010 10:00:07 +0000

Tim Wijgerde et al. are starting a very interesting project at Coralscience.org: they are building a low light reef tank (modelling “mesophotic” reef system) using equipment and foods available to all aquarists. I’m sure we “hobbyists” can learn and benefit from this work by marine scientists.

Read all about it here.

Special Diseases of Aquatic Organisms journal issue: The Role of Environment and Microorganisms in Diseases of Corals

Grumpy Old Reefer — Wed, 18 Nov 2009 06:07:30 +0000

A special issue of Diseases of Aquatic Organisms titled “The Role of Environment and Microorganisms in Diseases of Corals” has been published online. And the best part is that all articles are Open Access!

From the title page:

“This DAO Special contains papers based on presentations made at the 11th International Coral Reef Symposium (2008, Fort Lauderdale, Florida, USA). The contributing authors provide an update on coral disease research, including new advances in the microbiology of causative agents, epidemiological modelling studies, and the role of climate as a driver of disease. They also consider management needs in light of a rapidly changing environment of coral diseases.”

The best advice you’ll ever get

Grumpy Old Reefer — Fri, 06 Nov 2009 15:57:05 +0000

I was reading the popular Reef Builders blog the other day when I noticed this sentence in an excellent post by Scott Fellman titled Thoughts on Reef Aquarium Husbandry: “Good things done in small measures, with frequency.” :

The key to ultimate long term success in the hobby is not just having the ultimate system and the hottest equipment – it’s the effort that you put in as a hobbyist to provide your animals with the best possible care.

I can’t think better advice to give to a new (or experienced for that matter) reef aquarists. It is really important to understand the message: the success depends only on you and your actions. A good aquarist with mediocre equipment will always beat a mediocre aquarist with good equipment.

–––

I have a couple of my own, more grumpy advice:

Don’t just sit there, do something!

The saying “Only bad things happen quickly in a reef aquarium” has some merit but many have taken this far too literally. If you can see there is something wrong in the aquarium it calls for a immediate action. Don’t just sit there wishing the problem will go away by itself. There is absolutely no reason to prolong the stress the inhabitants are experiencing.

Only ask if you can’t find the answer.

I don’t agree with the phrase “There are no dumb questions, only dumb answers.” The question that has been asked hundreds of times is a dumb question indeed if it is repeated. You will learn a lot more by doing the research yourself.

And finally, one of my favorite quotes:

“Insanity: doing the same thing over and over again and expecting different results.”

- Albert Einstein

ULNS is not really L and far from UL

Grumpy Old Reefer — Wed, 28 Oct 2009 20:46:45 +0000

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!