Saltcorner
By Bob Goemans
By Bob Goemans
Hi Bob,
Thanks for responding to my question of an auxillary plenum. I believed plenums work, but I was always afraid to install one in the main tank, for if something had gone wrong, i.e., accummilation of detritus I would have to tear it down which would be a cumbersom task in the show tank. Call it piece of mind. I am now going to set up an auxillary plenum. However I have a couple questions that your book did'nt address. No fault of your own. Since this system of mine will be a "sump Type" plenum, the water level is not going to fill the tank all the way. Does this matter, if water level does matter , what should be the measurement from top of sand to top of water level? Secondly, can I use caribasea, special reef grade sand for my top 2'' and my bottom 2''? what do you recommend/ I got the impression that the bottom 2'' should be of larger grain size. --- I know you disagree w/ the use of kalkwasser, atleast the way I do it, because I just dose it w/out carbon dioxide, but I'd like your opinon on my kalkwasser preparation. I does it from a 10 gallon tank. First I fill 9 1/2 gallons of the tank w/ r/o water. Then I have a half gallon container filled w/ r/o water. I put the ten teaspoons(recommended for ten gallons) in the half gallon container, stir, and let sit overnight. I then open up a valve place near the bottom of the half gallon container, the kalwasser then drains into the ten gallon container w/out the scum on top and the undisolved particles on the bottom. This method seems to produce less precipitation on the bottom and top of my ten gallon tank. I figured my method produces the same quality and saturation as if I added the hydoxide directly into the ten gallon tank. Am I right or am I losing something by adding large quanities in such a small container then dumping it into the ten gallon tank. Your opinion would be greatly appreciated on all my questions. You have been a great help thus far. My tank is thriving. OOPs, one last question, How long does Reef vital dna, coral vital LSB, and selcon last in the refrigorator. Same w/ black powder and spectra vital in the freezer. Also supplements such as concentrated strontium, magnesium, and combisan at room tempurature. Sorry for this long email. But your advise is deeply appreciated.
Jasonn - Sweden
Hi Jasonn,
Thanks for your letter and moving my office equipment from my old office to my new office along with some badly strained chest muscles has put me far behind answering mail. I don't know where people get the idea that there is accumulation of detritus in the plenum area. My first system was set up five years and when everything had to be moved because they had out grown the aquarium, the plenum in that tank was as clean as the day I set it up.
As for remote plenum tanks, I agree they seem to be better for many people. In fact, I am currently finishing a new business office extension to our home here in Tucson Arizona that will be supplied by electrical power generated by solar panels and a wind generator. Its 180 gallon reef system will have a 40 gallon plenum-equipped aquarium located under the main show aquarium. The show system will contain about an inch of 1.5 mm grain size sand. Water will flow between the plenum tank and show aquarium at about 20 gallons per hour. There will be a few pieces of live rock and many different sponges in the auxiliary plenum system and it will not be lighted. I expect it to easily handle all bio-load. I plan on writing a couple of articles about this system that should appear in various magazines including Practical Fishkeeping sometime later this year. But remember, that's not a sump where other equipment such as a protein skimmer is going to be located. It's simply a biological filtration system plenum style! Plenums in sumps where there is fast water flow through them have "never" been recommended by me! Time for diffusion in a sandbed, and a reasonable volume of sandbed area must be adhered to. There are no magic things about a plenum system, they need their space and time to do their job!
As for your water depth question, it is a fact that shallower bodies of water have slightly lower pH than do deeper waters. That's because they absorb more carbon dioxide because of their larger surface area and retain it because it is absorbed more easily than oxygen. Anyway, if the container is sufficiently aerated, i.e., powerheads/airstones moving the water more vertically than horizontally, that should not be a problem. It is not necessary to over aerate, however, good water movement is such containers is highly recommended. By depth, anything over six inches should suffice. As for the type of sand, crushed coral would suffice for the bottom layer. As for the upper layer, CaribSea Seaflor Super Reef is my choice because of its slightly larger sand grain size therefore have slightly better control over oxygen gradients. As for different grain sizes in different bed locations, that is another something started by others not too knowledgeable in plenum mechanics. There is no truth that this benefits the system, and is not necessary as one size sand grain, as what the product mentioned has, will suffice nicely. I should add different sizes don't hurt the system, however, the time and effort in establishing them is not necessary.
The only reason I do not like the addition of Kalkwasser is that my aquarists use the dump and pray method! As for your method, only a small amount, probably a half teaspoon of Kalkwasser is dissolving because that is saturating the half gallon of water. This small amount of calcium would not be enough to maintain anything but a very, very small system. As for precipitation in the 10 gallon tank, the introduction of a Kalkwasser solution in this tank at least allows its pH to rise somewhat, lessening the precipitation when it enters the main system. Your method is at least a step in the right direction, however insufficient for maintaining proper calcium levels in larger systems. Your best direction is a calcium reactor, a two part solution, or the use of carbon dioxide equipment on a much larger amount of Kalkwasser.
Once the Marc Weiss products are opened they should be refrigerated and will last for many years. As for the other additives, they should also last for years at room temperature when opened. Where about are you located?
Hope this helps.
Bob
