I set up these three side tanks for remote system management. I can change things in the aquarium environment without redoing the whole system.
Here are some facts(yes facts) from keeping SW/FW aquariums 25 years. I have used nitrate denitrifying reactors, sugar, vodka, sulphur denitrification, electric plates system for ion denitrification, DSB, Plenums, 500g reservoir with 2 gallon per drip for semi open system, Bare bottom tanks with huge skimmers, and what have I learned?
1. The reactors work, but are high maintenance and require regular feedings and depending on bio-load require proper sizing(sometimes several units run in series) to work efficiently. These IMO are troublesome to use and I would not recommend them.
2. Sugar/vodka/etc. these are carbon sources containing forms of ATP which will illicit a heterotrophic bacterial bloom within the aquarium. These bacteria are present in very small quantities(when compared to nitrasomosa..sp?) but explode when fed a strong food source like sugar/glucose. They turn the water foggy white and are visible to the naked eye. They last about 72 hours and their respiration consumes the nitrate ion converting NO3 to nitrogen gas. Nitrates will amazingly disappear. WOW! The problem, many. Phosphates aren't affected at all and can have negative effects by causing the proliferation of hydrogen sulfide. too much sugar/carbon and the tank will lose too much oxygen and crash. IMO, this must be done in small doses and done carefully with the full understanding of the processes taking place. I do this monthly with sugar instead of vodka, however vodka is a cleaner source. I use 2 sugar packets for coffee for 280g of water. This is to boost bacterial populations and to accelerate the decomposition of detritus. I do not recommend that you use this without a complete understanding of carbon boosting.
3.Sulphur denitrification...works well, but again sulphur beads need to be replaced and certain sulphur systems need to be maintained/fed. Some of these processes happen in the plenum system naturally thru bacteria. I again do not recommend this system to the average reefkeeper. I also used a hobby sized system on a 240g reef and felt it was not properly sized to bio-load.
4. Electric plates...I am not even sure if these are still available. I believe the system was called the Nitrate Eliminator. I bought one and it worked but the plates had to be cleaned which meant too much maintenance again. Plus I wasn't comfortable with the design. I mentioned it because I used it once and saw positive results but remember it being too much work.
5. DSB...They work and I have one. What many people don't understand about the deep sand bed is how they work. the system is incomplete by itself. It will remove nitrates! Great! But it can store phosphates. Too many phosphates and you will see the proliferation of pockets of black hydrogen sulphide forming. DO NOT DISTURB THESE AREAS!!! Just reduce the phosphates as much as possible and the bacteria will convert the area back to the way it was before too many phosphates accumulated.
Phosphates are only part of the problem with a DSB. The second as Curt pointed out is ammonification! Yes, people ammonium is produced! That is why there is an algal food source at the surface of the bed when all water parameters say there shouldn't be. To offset these 2 problems we need to add a FAST GROWING macro algae. This will feed on the ammonium and aid in the reduction/accumulation of phosphates.
To properly use a DSB long term we need to understand that we must limit Phosphates as much as possible before they have a chance to cause any problems and we must have an algal form growing above the sand bed to help consume our ammonium.
I feed a large variety of foods and at large quantity to my reef. Flake foods are a part of that and are high in phosphates. Therefore I scrub with an iron oxide resin and have the fuge. I recommend using strong illumination over the fuge for faster growth of the algae. If you wish to use a DSB I would strongly advise that you add a separate tank (40g breeder) for this where the sand bed can have a large surface area exposed to water column(Not covered in liverock) and have alot of macro growing. I prefer Chaeto. I then strongly recommend the use of a iron based phosphate resin that is changed every 30 days. This should prove to provide a very healthy reef long term.
6. Plenum...very efficient and probably the best Nitrate reducer! The biggest problem is construction of the plenum and proper installation. The second biggest problem is that people place live rock above them. These again should be set up in a separate tank with say a foot print of 48"X24" or larger if space can be provided. The more surface area the bigger the bio-load it can process. I used a DSB because I did not have the materials or time to build the plenum. I regret not having a plenum but have adapted my system to still work as efficiently.
This guy custom builds plenums for you...Contact Todd Schwarz at
[email protected] for more info
7. Semi open systems...works great! Very expensive and requires space for water storage. Basically you mount a large container on a second level of the house (2 are better) and you use a drip line (1/4") to the main tank. Then adjust the flow to about 2 GPH and then install a drain at the desired water level of the sump and plumb it to a sewer. FW breeders use systems like this to constantly change the water. I tried it on a shark system and it worked but was expensive. If processing tap water at this size and salt was cheaper this would work well. It is not practical for most people though.
8. Bare bottom tanks...high maintenance! The point of a bare bottom tank is to remove the detritus before it begins to break down and foul the water. This means mechanical filtration and the use of a siphon to remove this material. Lots of work. It does make a cleaner system that will grow a healthy reef. I believe that there are easier ways though. This system requires the use of aggressive skimming.
In the end a large protein skimmer is IMO a necessity. Yes, you can run reef tanks without them, but I have always had better results with bigger skimmers. I also follow the aquarium industry in Europe and all of the phenomenal tanks I have seen have used very large skimmers. If your skimmer body is less than 30" tall I high recommend that a recirc mod be added to increase dwell time. I prefer skimmers with 4' tall reaction chambers. MRC is an excellent skimmer when sized to the proper pump. The plain and simple fact about the addition of a skimmer is redox potential. Your ORP reading will increase if you add a skimmer, therefore so does your oxygen levels and there is proof in the readings of the removal of DOC's. A definite benefit.
Finally let me say that all the above systems will create incredibly, healthy environments if the aquarist understands exactly how the system works, what work is involved to the proper maintenance, and has the time and resources to properly maintain each one. System crashes(outside of toxic animal releases) are always due to some human error, either in not setting the system up properly or by not understanding the NEEDS of the system you have built. They are not as common as they used to be in the late 80's and 90's but still happen because some element of the science of aquaria was misunderstood.
I recently did some work with a researcher from the Field Museum Chicago, she was a micro biologist studying corals with MRI technology. She knew alot but didn't know anything at all about aquarium husbandry. Captive systems compared to the reefs themselves are two completely different arenas and is why we really need researchers to look at captive systems as well as the natural reef.
To summarize, lets not only be concerned with nitrate reduction but also the reduction of DOC's and phosphates. Let's incorporate strong skimming, chemical filtration, and even U.V. Sterilizers and ozone to help our tanks be as healthy as possible.
