Saltcorner
By Bob Goemans
By Bob Goemans
Dear Mr. Goemans,
I enjoy your Sand-Mail column in FAMA and it's the only one I'm guaranteed to read each month. I have a few questions for you but first I'll give you some info on my system. I have a 120 gallon main tank with a 75 gallon sump. In the main tank I have a couple of inches of small aragonite sand with lots of live rock and corals. No green algae, but lots of coralline. Two 175W 10K MH with two VHO Actinic. There are also eight powerheads with two returns. I also have an 8 watt UV sterilizer.
On one side of the sump I have set up a refugium lit with two 8 watt PC. On the other side I'm trying to establish a propagation area with two 55 watt PC's. Since I put this system in I haven't used my protein skimmer (two months). I use a Calcium Reactor to maintain the Calcium and Alkalinity and I dose Strontium and Iodine. I should mention that I have had 2 different cases (one in summer of 2001 and the other about a year before that) where the Calcium went sky high (650+) before I realized what was going on. It ended up killing some frogspawn, torches, brains, etc.
Now the questions, easy ones first.
#1. I read in your January 2002 article that UV Sterilizers kill some wanted items. I read somewhere about UV's in FAMA and got the impression that I should upgrade to a much larger size. So now I'm unclear about whether I should have one at all or if I should run it just occasionally. If I do need one should I get a larger one. If so, what size and how do I know who makes the best one? Does anybody test them like they do woodworking tools?
#2. How often, if ever, should I clean the gravel in my main tank?
#3. Is there a definitive answer on the small starfish that I see in my tank? Some people say to remove them, others say they don't do any harm.
#4. Polyp extension. Some of my corals don't seem to extend their polyps as well as the ones in my brothers tank (Same setups and same water quality. But different lighting. He uses four VHO's and two 55 watt PCs. He is still using a skimmer and he does have outbreaks of algae sometimes - I never do). Some examples- my Christmas Tree rock worms won't come out during the day, but do at night. His come out all day. I took a Xenia from his tank that was doing great and put it in my tank. After 3 days it had never opened up (it was on the bottom). When I took it back to him, it opened up the next day. His brain corals seem to always have their tentacles out, where mine never do during the day. I have a plating Montipora that has grown to over a foot, when I chipped a piece off and put it in my propagation area, the polyps came out where I could see individual polyps. I then put my Christmas Tree Rock in the same area and the worms came out almost immediately.
My first guess to my extension problem is lighting. My main tank is in a wall, so I'm able to adjust the height of my lights. They are now about 10" above (previously about 6-7") the tank. Should I have a protective sheet between the lights and tank? I never put one on because they were so high I wasn't worried about splash. My second guess-is it possible that I have something wrong with my water quality that I'm not testing for? Or not feeding enough? Over all I would say that I've been successful in my 5 years of having reef tank. I had a red open brain split in half. A Trumpet go from 8-10 heads to over 60. A Blastomussa that I was able to catch a 'bud' off and put in my sump where it has turned into two new ones. But it is frustrating to not be able to have Xenia or a Christmas Tree Rock or see the polyp extension that others have. Any help would be appreciated.
Thanks,
Greg Dudley
Hi Greg,
Thanks for your email and good questions. As for UV sterilizers, and/or the application of ozone, I see them both as good devices should fishes in a complex reef system develop Amyloodinium or Cryptocaryon. Otherwise, their use does destroy entities such as floating microalgae, bacteria, viruses, etc as mentioned in that article. And, some of that can be used as food for corals. An adequately sized UV or ozone generating equipment in reserve is like owning car insurance, nice to have and hope you never have to use it! And if it were my UV for that size aquarium, I would increase its capacity. Yet, only use it if the need arises.
Some UV manufacturers recommended a minimum flow rate of about 25 gallons per hour per watt. They also recommended that the volume of the entire aquarium flow through the sterilizer once every hour. Therefore a 4 watt unit may provide protection for a 100 gallon aquarium by operating for one hour. 'May' is the key word! My recommendation would be that at a minimum a 15 watt unit for a 100 gallon aquarium be used at the same flow rate. This provides a sure kill ratio since proper maintenance of these units and/or correct flow rates are rarely achieved. As for brands, there are many and I'm not familiar with all the current brands or if anyone can relate to one brand being better than another. I would stay with a well-known brand name.
As for vacuuming the substrate, any type sandbed should receive a general cleaning once a month. I've often heard the comment sandbeds should never be cleaned. If possible I ask those people if they never dust their home! Anyway, cleaning depends upon bioload, and generally most detritus is generated from fish waste. You don't mention how many or size of the fishes in your system, but presume there are some. Therefore, at a minimum I would recommend vacuuming the accessible sand areas, reaching down into the full depth of the sand, once a month. In-between that cleaning I would stir the sand with a chop stick or something similar as the stirred detritus makes a very good food supply for various polyped animals and/or tube worms. The stirring also prevents deeper sand areas from performing the ammonification denitrification process found in areas where oxygen is depleted, such as in areas below about an inch deep.
The small starfish you name are probably Asterina anomala, which are usually less than three-quarter inch and having up to seven legs. They have apparently come from Fiji on live rock. They appear to be sps, soft coral and coralline eaters. These tan dime-sized or smaller, yet large bodied starfish are sometimes visible at where the substrate meets the aquarium side panels when the aquarium lights dim. They also hide by day under corals. They divide themselves across the main body producing stars with half a body with two to three legs of various lengths. A long pair of stainless steel tweezers is a good tool for their removal. A natural predator would be the harlequin shrimp Hymenocera picta. I take them out 'every' time I see one!
As for polyp extension, that's a more difficult situation to resolve. Let's first look at the Christmas Tree rock worms. I keep my Christmas Tree worm rock about ten inches from a 250W 10K MH lamp and about ten inches from the outflow from a system return pump, which flows at about 700 gallons per hour. Thus their symbiotic relationship with the live Porites coral coating the rock is maintained. It is thought the worms derive nutrition from the coral mucus and in my aquarium these worms are always out where they are constantly being moved by the strong water flow. If the Porites dies, so do the worms sooner or later. Your situation could possibly be lack of water movement/light intensity, and/or the lack of Porites to supply their diet needs. Opening at night could be an indication they are looking for plankton that may rise during the night to supplement their diet needs, or something during the daylight hours is picking on them.
Xenia is sensitive to nitrate levels over 5 ppm and may deteriorate if nitrate level exceeds 10 ppm. It is also sensitive to oxygen levels. Your brother uses a skimmer that oxygenates the water (you apparently don't use a skimmer and I can't fathom why anyone would not want to use a skimmer!), and pulsating may be related to ridding excess oxygen, which can be highly toxic to the animal. Placing a pulsating Xenia in a tank at the bottom of a tank where dissolved oxygen was not as high as in the previous tank could be a reason why it decided not to pulsate. Just a thought, but you may want to check it out by restarting your skimmer.
As for tentacles being out on some animals, that's usually a sign they are hungry which is the reason they have tentacles. They have other means of protecting themselves, but tentacles are feeding mechanisms. Depending upon the food present or feeding regiment, their tentacle display is related. Checkout the feeding routines and what is used, when and how much, and then compare notes.
When it comes to the distance the lamps are from the surface of the water, there are only two considerations in my opinion and they are the heat generated and splash/safety. If they are in a hood with a splashguard and the aquarium has a chiller or their heat is not a problem, then I want my lights as close to the surface as feasible. We need to realize the further away the source of light, the less light reaches the target organisms. If your lamps are not shielded, I suggest doing so and moving them closer to the water surface. But that doesn't mean installing a cover over the entire aquarium as that would interfere with good gas exchange.
A refugium on some installations helps with maintaining a more natural pH and alkalinity level, especially when lit at an opposite timeframe than the main system. Since your main aquarium sandbed is shallow and directly on the aquarium bottom, a refugium is a good addition. Also, with the refugium's light source close to photosynthetic frags, it makes for a good propagation area.
All in all it sounds like you are having good success with your system. Could be some minor changes as recommended above might provide the improvement you're looking for. Hope this helps and keep me posted.
Bob
