Saltcorner
By Bob Goemans
By Bob Goemans
Hello Bob,
I wrote to you twice in the year 2003 when I was planning to start my first reef tank; in fact, my letter and your answer were published in April 2003 issue of FAMA magazine. Because of diverse circumstances it did not get started until the beginning of 2007. I tried to follow your main suggestions (I have all your books, including the last one - The Marine Fish Health and Feeding Handbook), but am experiencing high nitrate and phosphate values that I am not able to control.
Main concern is with nitrates because I will soon possibly decrease phosphate levels (now at 1.52 mg/l) by decreasing food quantity and using a phosphate remover. Yesterday introduced a canister filter with 1.000g of ROWAphos phosphate remover. - Concerning nitrates, they are difficult to reduce; have made three 80-liter water changes last week. Nitrates remain between 21 and 27 mg/l NO3-N and I don't know what else to do and ask once again for your opinion.
Main tank: 1500 X 650 X 650mm, live rock 70 kg (Fiji), synthetic rock 20 kg, coral sand 4 cm (1 - 3 mm); and most rock is not in contact with the sand.
Sump: 1300 X 500 X 500mm with plenum built according to your instructions (5 cm till the grid, 10 cm sand (4 - 5 mm); water coming and leaving the plenum at 60 liters/hour; and also a Refugium 250 X 500 X 500mm containing Miracle Mud, Caulerpa, Chaetomorpha and lit at night.
Skimmer: Deltec APF 600, Calcium reactor: Knop S IV filled with Knop media. Illumination: Solaris LED light 375Watt - 60” + four T5 39W (two actinic + two 10K). Pumps: return from sump Eheim 1262, circulation pumps: two Tunze Nanostream 6055 + one Tunze Stream 6100, controlled by a Tunze 7095 multicontroller in pulse mode.
Fish: 1 Acanthurus leucosternon, 2 Premnas biaculeatus, 1 Synchiropus splendidus, 1 Nemateleotris magnifica, 1 Chelmus rostratus, 1 Salarias fasciatus, 1 Siganus vulpinus, 1 Forcipiger flavissimus, 1 Ctenochaetus strigosus, 1 Centropyge loricula, Neocirrhites armatus, 1 Psedocheilinus hexataenia.
After solving this crisis I would like to buy 4 Pseudanthias squamipinnis (1 male + 3 female); do you think it will be feasible or is the aquarium already overloaded in your opinion?
Corals: Physogira, Euphyllia (4), Nemenzophyllia, Turbinaria peltata (2), Acropora, Duncan coral (2), Lobophyllia, Blastomussa (3), Scolymia (2), Fungia, Caulastrea (2), Favia (2). Tubastrea (2) + several soft. Inverts: 3 Turbos, 2 Hermit crabs, 1 Ophiarachna incrassata, 3 Shrimps. In spite of nitrates and phosphate levels, the tank has no algae; the tank has lots a small snails.
Water parameters: KH = 10 dKH, Mg = 1280 mg/l, Ca = 500/510 mg/l, NO3- N = 22 mg/l, PO4 = 1.52 mg/l, Temp = 25.8ºC, Salinity = 1.024/1.025
Tests used: Salifert for KH, Mg and Ca and electronic photometer for NO3-N and PO4 (Hanna Nitrate Photometer and Martini Low Range Phosphate Photometer).
Normal Maintenance: Water changes 80 liters every 8/10 days; RO/DI water, Red Sea Coral Pro Salt; yesterday I tested nitrates and phosphates in this water before water change (NO3-N = 2.0 mg/l, PO4 = 0.15 mg/l).
Once a month I vacuum the bottom of the main tank; I never vacuum the plenum area; the plenum area has no rock, no light; the sand is not compacted.
Feedings: Fish: In the morning1 dried sheet of algae (10 x 10cm); after lunch 4/5 ml of varied dry foods (granules); after dinner 2 cubes (4 grams each) of varied frozen foods + a small quantity of vegetal dry granules + a pinch of Cyclop-eeze. Corals: twice a week, using a pipette, 4 half cubes (8 grams) of varied frozen foods + a pinch of Cyclop-eeze + 5ml of Salifert Coral Food; twice a week - 10 ml of Salifert Coral Food (liquid). Do you think this is too much? Probably the coral regime is excessive…
Supplements: Iodine Salifert 5 times a week (total week doses = 60% Salifert recommendation); Trace Hard and Trace Soft Salifert twice a week (total 70% Salifert rec.); Strontium Salifert once a week (30% Salifert rec.)
Some corals are very well, but the majority is not well expanded; I had some loses lately (Euphyllias, Trachiphyllias, Turbinaria reniformes, Alveopora, Goniopora, Catalaphyllia sp. (Catalaphyllias never open in my tank).
I thought to buy a nitrate reductor (Aqua Medic Nitrareductor 10.000) to help solve nitrate levels. Would like to hear your opinion about this matter.
I hope you can help me, and thank you in advance for your help and patience
César Silvério
Lisbon, Portugal
Hi César,
Thanks for a well-written letter and I must say you have 'excellent' equipment and a well cared for aquarium with an array of very nice animals!
There is however some comments and thoughts I'd like to present, therefore, lets take each separately as we work our way to your main question as to nitrate levels.
Your aquarium is about 175 US gallons with about 1 pound of rock per gallon, which is prefect in my opinion. Even better, most is raised off the bottom shallow 1.5-inch sandbed, allowing for improved bed maintenance.
As for the plenum grid, if I understand correctly, the plenum 'space' is 2 inches (5 cm), i.e., the grid itself is off the bottom by 2 inches. If so, that's unnecessarily high, as .5 inch (1 cm) would have sufficed. Yet, even though wasting some height in the plenum container, which is sized correctly for your system, it will not detract from accomplishing its functions.
The fish load is maxed out in my opinion, and adding four Anthias would increase the need to feed more, resulting in increased nitrates. Also, they are somewhat shy fish, and the Power Blue might harass them, causing them to hide most of the time or possibly develop Marine Ich (Cryptocaryon irritans). I think your diversity in the bioload is extremely good and you're fortunate to have all living together healthful and peaceful. I highly recommend not adding to the bioload.
As for coral losses, Euphyllia species prefer moderate light and gentle water movement; Trachyphyllia also prefer the same, with bottom areas their best location; Turbinaria reniformis just the opposite with bright light and very good water movement; Alveopora and Goniopora liking muddy/high nutrient locations with gentle water movement and low to moderate lighting; and the same is true for Catalaphyllia. Maybe this is helpful.
As for the test results of the water prepared with Red Sea Coral Pro Salt, I find the phosphate (PO4) result surprising and suggest testing the effluent from your RO/DI unit to be sure its media does not need changing. Even though I've seen some reports of PO4 being found in various newly mixed waters, I use the same product among others, and am using a Merck test kit and found zero PO4, and no nitrate (NO3) using a Salifert kit. I consider this brand salt among the best on the market, yet, you may want to try D-D H2O Pro Salt next and give me some feedback on its content and resulting aspects of life in the aquarium. But be sure to test the water being used prior to adding the salt mix.
Where phosphate 'in' the aquarium is concerned, the majority comes from the foods fed the fish and inverts. This is not to say your fish feeding regimen needs changing, but do recommend the coral feeding be suspended, as much of that food goes to waste and results in both PO4 and NO3 increases. And anything above 0.015 mg/l PO4 in the aquarium itself is too high in my opinion. However, the addition of ROWAphos in a canister or reactor filter will dramatically correct that situation. And change the media as needed to maintain reading at or below the above mentioned level.
As for your NO3 level, they are not critical, and water changes in an established aquarium is one of the least effective ways to correct levels that are over recommended maintenance levels, which in your aquarium with its fish load and feeding regimen would be, in my opinion, preferably no more than 10 - 15 mg/l. Keep in mind when a water change occurs, only a few mg/l drop/change will initially occur. Within a couple of days nitrate will again be at or near its former levels! Odd, and many wonder why this happens. Actually, it seems like in previous tests in systems with lots of live rock and/or deep beds, the nitrate in them would enter the bulk water after a water change, reestablishing the previous bulk water level, or close to it. And because I have tested this in several past aquariums having different environmental interiors, I believe water changes are not the way to go to control excessive NO3 levels. Aquarium cleanliness, proper filtration, and sensible feeding regimens should be used instead. As for the Aqua Medic Nitratereductor, that is worth trying, as it only needs its Deniballs replaced once yearly to insure proper operation,
Therefore, stopping the coral feeding, greatly reducing the PO4 (which may have interfered with coral growth and been part of the problem with losing some corals), and the addition of this Aqua Medic device, should greatly help resolve the PO4 and NO3 situation.
Furthermore, I think your calcium is somewhat high - my preference is calcium in the 380 - 430 mg/l range while maintaining alkalinity in the 2.5 - 3.5 meq/l range, with pH in the 8.1 - 8.3 range.
One thing further, even though Salifert products are excellent, when it comes to iodine, very accurate hobbyist test kits are not readily available, yet it should be tested, as adding any chemicals without fully understanding their impact is not good animal husbandry. And overdosing may also is a factor with coral losses. Even though a few different brand test kits exist I don't recommend hanging my hat on their results. Consider them a guideline. And when testing for iodine it is important to know whether the test result is total iodine (iodide + iodate), or that of only iodide. When the aquarium's iodide level reaches 0.04 mg/l, no further iodide should be added until it falls below this level. If the test kit being used reads total iodine, do not add further iodide treatments until the level falls below 0.5 mg/l.
And no matter what brand is being used, suggest cutting the recommended iodine dosage in half and dividing that amount into equal amounts and applying them three times during the recommended dosage period, e.g., if 12 drops was recommended every week, would use only 6 drops and apply 2 every other day. As with anything that will be put into our aquariums, questions should first be asked as to how it would interact with what's already in the aquarium. In fact it would help to at least know the general makeup of the product before using it. And the same goes for trace elements, reduce the suggested dosage to one-third and apply for three months. If animals continue to look good, try one-half the recommended dosage for another three months. If continuing to look good, try three-quarters for three months. If still good, go to recommended dosage and stay with that brand. And also suggest testing for Strontium to make sure you're not overdosing.
Finally, the separate refugium with Miracle Mud, Caulerpa, Chaetomorpha and lit at night is fine, as that somewhat helps maintain alkalinity, and slightly helps to reduce nitrates.
I hope the above has been helpful.
Bob
