Saltcorner
By Bob Goemans
By Bob Goemans
Hello Bob,
Thanks for your quick response to my last email. I wrote regarding nitrate questions and the natural reef denitrification system. I bought the test kit you recommended and it reads zero to a slight trace of nitrate. I'm also now showing trace nitrate-nitrogen readings with some other brand test kits. This is very confusing because when I initially wrote you my nitrate reading was approximately 20 ppm and I 'was' testing nitrate-nitrogen. I now realize I did not explain which brand kit I was using, therefore you thought I might only be testing for the nitrate molecule, not the nitrogen portion of the compound. However, the drop in nitrate came after we experienced a power failure and the tank was without power for about 12 hours. After the power came back on I accomplished a 15% water change and then tested the nitrate. It was extremely low! Does this acute drop in nitrate make sense to you?
Also, I'm now having a battle with algae, and not winning. I reviewed your booklet Marine Algae Control Secrets, and Julian Sprung's Algae Problem Solving Guide. A plethora of great information in both! However, one of my biggest problems is that I'm red/green colorblind so proper identification of some types of algae is very difficult for me. I will send some photos with this email so you can see what I'm talking about. I also have a few other questions:
1. I have been using very small doses of a product that contains potassium permanganate. Even though it may be a waste of money, it makes me feel better to see my ORP rise to over 400 and stay there. Yet, I don't understand how or why this chemical works, therefore decided to stop its use until you can shed some light on this topic.
2. About five months after my reef system began I had purple coralline growing on the back tank wall and all over its small amount of base rock. But I have not seen any new purple coralline growth in the past three months. In fact my once perfect bright purple Fiji rock is now dull and becoming overgrown with what I think is brown diatom and some hair algae. Also there are parts of the rocks turning grayish tan. I will also include some photos of this.
3. There is always a lot of diatom algae collecting on the front and side walls and if I don't clean them every day it becomes a lot of extra work to get them clean. Also in my overflows there is a large amount of long brown algae that looks seaweed-like. I decided to let it grow so it would consume nitrates since it was out of sight. Am I off base here?
4. There are three 175W MH 6500K lamps, and four 72" T12 VHO lamps (two super actinic, one actinic white, and one wide-spectrum lamp). The super actinic lamps are on for 14 hours per day, the other two VHO lamps are on for 12 hours per day, and the MH lamps are on for 10 hours per day. These bulbs are all eight months old. Do you think the age of these lamps has something to do with my problems regarding the coralline growth? I was planning to replace them in about 4 - 5 months. Does this sound correct?
5. I have a 200 gallon eight foot long tank with 4 outflows (two on each side, and two in the middle), running approx. 2000 - 2200 gallons per hour total current with an Iwaki MD 70 RLT and Custom Sea Life T-3 water pump. I siphon detritus weekly and pluck as much hair algae as possible every couple of weeks. I also siphon and mix the sand bed. At this time I'm not utilizing any powerheads or wave makers. How important are wave makers and would it behoove me to use them/one, and where should I place them?
6. For a cleanup crew, I have about 125 red/blue hermit crabs, 2 horseshoe crabs, 1 large Sally Lightfoot crab, 2 - 3 Emerald crabs, 2 Banded Coral Shrimp, 1 Scarlet Cleaner Shrimp, 6 Peppermint Shrimp (that I haven't seen in about 4 months), 3 brittle stars and about 75 assorted snails. In a past issue of FAMA you mentioned the common sea hare, and the Lettuce Slug as possible helpers. Do you think they would help me as well? If so, how many would I need, and where could I find them? Are there any downsides to utilizing these animals, besides cleaning up after them?
7. Would I benefit from placing macroalgae in the tank?
Also, there is approximately 250 pounds of live rock, with 75 pounds of base rock piled single filed so about 65% of the sandbed is exposed (sandbed is about 2" deep). Water make up is done with an R.O., which I'm about to add a deionization canister. I do a 15% water change every 4 - 6 weeks via tap water filter (deionization cartridge). I am presently looking for the phosphate reducing pads you mentioned in a previous Sand-Mail column. Have also been using a cheaply made protein skimmer, but after reading your reviews of several brands, have decided to acquire a much better brand, one which has a John Guest fitting for my calcium reactor.
The only thing that I add to water is iodine, and I feed brine shrimp and red or brown seaweed daily. My present water values are as follows: pH 7.9 - 8.1, ORP 380mV, Temp. 76 - 78F, SG 1.025, Ca 420 ppm, dKH 24, Alk. 8.5 meq/l, Nitrate 2.5 ppm, and Phosphate 0.1 ppm. And I only have seven fish, 2 Maroon Clowns, 2 Green Chromis, 1 Coral Beauty, 1 Sixline Wrasse, and 1 large Yellow Tang.
My immediate plan is to try and decrease my PO4 levels and utilize a more efficient protein skimmer, but I am very concerned about the condition of my live rock, and the lack of new purple coralline algae growth. Wondering if the damage done is reversible, and don't have the first clue as to how fix it, if possible. Hope this is enough info for you. Thank you in advance for you response as your advice means a lot to me.
Thanks again.
Brian Tapasto (Charlotte, NC)
Hi Brian,
Thanks for your feedback and further information/questions, of which I wish I had all the right answers! Let's first address the nitrate situation. If you had an undergravel filter and lost power, the nitrate drop would make 'some' sense. In fact, that's why Sam Gamble got involved many years ago when the plenum method was still a mystery. The systems having an UGF in the public aquarium where he was the head aquarist actually did better than those where the sandbed was directly on the aquarium bottom during a five day power outage, and they also had a significant drop in their nitrate levels! Anyway, the loss of oxygenated water in your system may have created more zones for denitrification. A water change would have contributed somewhat to that reduction. Or you may have incorrectly read the tests kits the first time. But the good part is that a nitrate problem no longer seems to exist.
As for the potassium permanganate product, it burns up/oxidizes the organic matter in the water, which is what lowers the redox, therefore making the water more clean/clear and thereby raising the redox/oxygen content in the water. Not something I would recommend be used on a continuous basis, however, it can occasionally be used to improve water quality in aquariums where overall system organic content is too high. That's a nice way to say system husbandry is no longer what it should be! And it's a product that should never be used if the system is not equipped with an ORP meter, and keep in mind, anything over 400 is chancy!
Coralline algae or the lack of it is often a question. Usually I find the problem in the area of improper maintenance of alkalinity, salinity, and/or magnesium. In your case, alkalinity appear far too high and would suggest reducing it to about 3.5 - 4.0 meq/l, and also testing for the magnesium level, which must be related to salinity before being adjusted. When you have the magnesium level, let me know the aquarium's salinity and we will go from there.
As for brown diatom on the side panels, there are a couple of reasons for this nuisance. One, your tap water is probably high in silica, and I know of only one brand RO/DI unit at this time that will fully resolve that situation, and its described in the Product Review section on my website. Once you read that review, you'll understand fully why I recommend and personally use this brand unit. Once the water coming into the aquarium is fully processed, a second source of silica/silicate is from a very active nitrification process where some silica-like byproducts are produced. Stirring the sand too often only causes the bacteria to have to reestablish itself. Ever notice how the sand surface turns a little brown after vacuuming it! You may want to reduce the vacuuming to once a month, and give some thought to your brand RO equipment. Or at least contact the company in my review and ask them if they have some add-on equipment that could resolve the silica/type of silica that is presently slipping through your present equipment.
As for the stringy brown algae in the overflows, I'm not sure what that is. But, whatever it is, that area needs more frequent cleaning. I would not simply allow it to go on without cleaning it out. Possibly, it's only a diatom that has compounded itself because it has not been removed and the silica/silicate and light spectrum continues to be there for its growth. You might want to take a little bit and look at it under a microscope. Hopefully, the algae cell does not have a tail, therefore a diatom. But if it has a tail, its then a dinoflagellate and other steps need be taken, besides a good cleaning.
I see no need to change your lamps at this time, as the MH lamps should be good for about 16 months. The VHO lamps, if they have end caps/or their ends are not too dark, should at least last for about 12 months. And that's total life span, not an additional number of months. Also, I recommend upgrading to 10K instead of 6500K when the time comes. Your eye will like the change! Without knowing the type corals are in the aquarium, I can't judge the photoperiod, however, for most soft corals and some medium light loving stony corals, your photoperiod appears to be okay.
You have quality pumps and the total flow appears to be good, and with four outflows, I would surmise the system's circulation is at least fairly good. Yet, if anything, the flows are always the same direction and because of that, some dead spots in the tank will probably develop. That's where a quality wavemaker comes in handy! By causing on again and off again currents that interact with existing steady flows from your outflows, different circulation patterns will develop. This greatly benefits everything in the aquarium. Where to place powerheads hooked to a wave-making device will take some experimentation on your part. First, they should be where they can always be easily serviced, yet not too conspicuous. And of course where they do what you need them to do.
When it comes to sea hares, they are gluttonous algae consumers, and if you're willing to try one, it would probably have to be special ordered as they rarely show up in the trade. Those who have tried them tell me they are capable of quickly wiping out undesirable growths of algae, in fact, any kind of green algae! However, once under control the animal needs to be moved to another area where there is sufficient growth to support its needs. Lettuce Slugs are probably ok for smaller systems where their movement can be monitored, but in your large system you would need too many. One sea hare would equal a hundred lettuce slugs! And as for placing macroalgae in the tank, I would first get the new skimmer going and correct alkalinity, and if possible try a sea hare before adding macroalgae. You might also want to try applying a small amount of ozone to the new skimmer, as that will help maintain a more stable system ORP than using the liquid product mentioned.
Would also concentrate on lowering the phosphate level, as 0.1 is far too high. A reading of 0.015 or below should be the goal. And either the pads mentioned or one of the several powdered ferric hydroxide, i.e., iron-based products is the way to go. These pads should be available in the better local shops, or via mail order. If you go with the powdered form, its best used in a canister filter. If you need more information about which products and exactly how to use it, contact me. And I recommend including mysis shrimp in your animal's diet.
Let me add, there's an 'Algae page' on my website that contains photos of about 150 species of algae (good and bad) plus 60 known biological control species (fish and inverts) with the control species cross-referenced to the unwanted species of algae. And my new "revised" Marine Algae Control booklet mentions many new species of algae, and their photos can be seen on my website.
Hope this helps.
Bob
