Saltcorner
By Bob Goemans
By Bob Goemans
Dear Bob,
I have been keeping marine fish for many years now and have not had any problems till I recently 'graduated' to stocking some corals in my tank. The tree coral and mushrooms seem to be shrinking with each passing day and I am not sure what needs to be done... Could this be due to overstocking? The other two coral you see in the attached picture are two weeks old and seem to be alright for now.
My setup is a typical one with undergravel filtration, an Eheim canister filter with activated carbon and ceramic cylinders, a chiller to keep the water at around 25C and an Azoo in-tank protein skimmer. The filter you see on the top left is also of a biological nature. Too much biological filtration? Maybe... But without a sump, can biological filtration be achieved otherwise?
For lighting I am using two 42" fluorescent white and 1 actinic blue. This particular 4 foot tank has been established for over 4 years now with coral sand and live rock.
I add various supplements like strontium, iodine, liquid gold plus, invertebrate smorgasbord and marine trace elements as directed by CoralLife. Plus do PH buffering frequently. I vacuum the sandbed once every one to two weeks and make partial water changes once every 2 weeks using water filtered through a phosphate, nitrate and chlorine stripper.
I have a strong feeling that the problem lies in high phosphate and nitrate levels due to the breakdown in fish waste as there are 10 fish, an eel and a starfish living in my aquarium.
Food wise, I use sinking marine pellets and frozen brine shrimp for most of the fish and fresh shrimp for the eel and starfish. My sea apple does not seem to want to feed and has been getting smaller and smaller over the past year.
Also, green algae does not seem to grow in my tank, but brown ones do exist... I do see red algae forming as well.
Any suggestion on how I can improve the quality of the entire system would be very much appreciated. I am thinking of adding a calcium reactor sometime this year, but want to get everything right first.
Eagerly awaiting your valuable advice...
Sincerely,
Ben Wong (Singapore)
Hi Ben,
Thanks for your email and I think the first thing to do is check nitrate and phosphate levels. As for biological filtration, you can never really have too much biological filtration as bacteria exist in relation to the volume of incoming nutrients. If their nutrient supply dwindles, so do their numbers. On the other hand, insufficient area for their existence can lead to an aquarium where small amounts of ammonia continue to be present. Also, 100 watts of light for a 4 foot tank, which I'll assume is a 75 gallon tank, is insufficient for photosynthetic corals. Consider 3 - 4 watts per gallon a yardstick.
High phosphate levels could well be the cause of the problem and if so any of the iron impregnated phosphate removing pads would quickly help bring it under control. However, feeding liquid invert foods in no way benefits fishes as they get their vitamins and minerals from the food they eat. If your goal is to feed corals, including a Sea Apple that is starving to death and may soon poison everything in the tank because its shrinking, the best foodstuff to use is a product called Combo Vital made by the Marc Weiss Companies.
As for cyanobacteria, what you call red algae, that is a normal reaction to a situation where the nitrification cycle is far too active because of the excess nutrients in that area. That would be another sign the aquarium is being overfed especially with products that are not benefiting its inhabitants. Brown algae, such as diatoms, can be caused by having silica in the incoming water supply, which would mean a RO/DI system is needed to first process the water.
A calcium reactor would only be needed if the goal were to maintain more water quality specimens such as some stony corals.
If it were my aquarium, and the phosphate and nitrate levels were too high, I would only use products designed to maintain calcium, alkalinity, pH, small amounts of iodine and strontium, feed my fishes/starfish only what they can actually eat (feed as often as needed in small quantities) and use the Combo Vital product to fatten up the Sea Apple before that causes a problem. The Combo Vital product will also be eaten by other invertebrate, including the starfish. I would also quickly use an iron based phosphate removing product to lower PO4. Little by little the system should improve.
Hope this helps,
Bob
