Saltcorner
By Bob Goemans
By Bob Goemans
Hi Bob:
I wish to commend you on a Sand-Mail response in a past issue of FAMA. You cleared up many questions that I have been pondering. I used to work for an Aquarium store and also took on some maintenance clients as well (the store offered no such service at the time). What you pinpointed was the fact that many snails and hermits can have an adverse affect on algae. My theory is that they are merely weed eaters not weed killers. If introduced into a system with no or little algae and quality live rock they will do a good job in maintaining its beauty. However as you stated they won't solve the problem and overstocking of such critters can lead to more nutrients as they die without notice. In my experience in tackling systems with excessive algae growth it is to scrub the rock. Out of the tank is preferred, yet in tank with a siphon works well also. What I found works great is using a toothbrush attached to the end of a diatom filter. It can be hard work, but is well worth it.
My question is; have you seen any correlation between cyanobacteria and low temperatures? Previously I owned a 55 and 30 gallon live rock fish-only tanks before I moved to Japan. The 55 had a plenum and the 30 just straight sand. Each had 1.5 lb. of quality Fiji live rock per gallon that was properly cured by the distributor and then I placed the rock in a holding tub with a skimmer, herbivores, and actinic lighting for a week to avoid placing any excess die off in the tank. It was then rinsed using saltwater through a powerhead.
Here I have 20 gallon setup like the 30 gallon. They all have adequate skimming and water changes are performed as well as proper maintenance. Let me say the lighting is not where it should be, with only 3 watts a gallon. I used my aquariums to test on so I could better understand problems in others. I ran all of them without a heater for a while and noticed that cyanobacteria began to form when the temp fell below 75 degrees Fahrenheit. I never let it get below 70 because of the fish, which was a low load. After placing heaters in the tanks and slowly raising the temp to 78 I found that the cyanobacteria began to dissipate. No other changes were made during the heating test. Have you seen this before or was it pure coincidence? Rarely do or should any aquariums fall below 74 degrees, but I was puzzled when this occurred. I have read and experienced algae blooms with temps above 80. While diving I have also seen that hair algae and blue green algae occur in shallower depths and warmer waters. I know many factors effect algae so I want to study all of them to better care for the precious life that encompasses our hobby. If you have any input or know of any articles that show and prove relations between temperature and algae it would be helpful.
Thanks,
Joseph Cortez
Okinawa, Japan
Hi Joseph,
Thanks for your email and interesting questions. Temperature is not of any significance when it comes to the proliferation of cyanobacteria in the noted range. Nor is temperature, in my opinion, the primary cause of coral bleaching! However, in both circumstances the quality of light seen by the organism is of significance. Cyanobacteria are enhanced with red waveband light. Corals are not. When surrounding water quality changes, which includes density changes and/or skewing with improper use of additives, light refraction may be affected. Change the shorter blue waveband lengths to longer red waveband lengths and corals suffer, yet cyanobacteria benefit.
In your example the lower 70 degree water may have slowed metabolism in many of the aquariums creatures thereby resulting in a more nutrient rich environment, which in turn benefited cyanobacteria. As temperature increased to more normal levels for these creatures, their metabolism increased and better used the food supply. Surrounding waters then became somewhat less nutrient rich and cyanobacteria levels dwindled.
Bob
