This question came up in another thread based on an observance and another comments.
My observance is that when I dropped my Salinity to 1.021 my zoos started closing up and looking sick. When I brought it back up they perked up when it was over 1.023.
Anoter individual stated he never could keep zoos than got a new hydrometer and found his salinity was up in the red zone. When he brought the salinity down his zoos perked up and now they are flourishing.
Our suspicion is that zoos may be more sensative to salinty levels than many other corals are. so we would like to discuss where everyone with beautiful fast growing corals are keeping there salinity.
Then the question goes if salinity is so important what about other levels alkilinity, calcium, and magnesium?
Great thread, and only 16 replies, wow ??????????
I know I may be in the minority, but I base my opinions on data and personal experience when I say this.
It's not that zoanthids are sensitive to salinity/specific gravity levels, it is the sudden to dramatic shifts or flucuations of it.
I have viewed data which shows varying reefs around the world with Speicific Gravity measure at 1.010 to as high 1.030. That is a whopping .020 variation. Back in 2003, I maintained a well stocked system of thousands of polyps at a SG of 1.022. However this was done with the strictest care in keeping that reading as constant with diligent monitoring. My growth was crazy, but I then made gradual increases until I reached a new level of 1.025 to 1.026 and my growth was off the charts. It was one of the factors of which I believe contributed to the explosive and unstoppable growth I had along will careful husbandry, (knock on wood).
As it relates to zoanthids, finding that happy medium and mainatining it is what is key in my opinion. Example, if you have varying zoanthids from diverse regions around the world, collected at different depths and diverse conditions, will all of your polyps grow or expand exactly the same? In my opinion, maybe, maybe not. If I have polyps that were collected at a slightly lower SG than my system, and others from a region with an SG higher than my system, and polyps I received from Junior Samples who SG was also different, it would stand to reason that some of these polyps are going to retract as a result of these varying reading. However, it by making minor to gradual changes in SG until one finds a happy medium of which expansion occurs for all polyps, then that is where I would choose to set my SG. I would however shoot for readings within the 1.024 to 1.027 SG and only you can determine the appropriate levels for your system based on and considering any other corals and inverts in said system.
The use of cheap hydrometers for a system with hundreds if not thousands of dollars in livestock just baffles me.
Hydrometers measure observed gravity, not specific gravity. Countless tanks have crashed along with total coral mortality as a result of a simple hydrometer. Beat me up if you want, but I will never deviate from that statement. Troptrea and I spoke of it in a previous thread. I agree with Cubbies, dump the hydrometers.
I think it is interesting to note that Troptrea had a mere .002 shift in SG which yielded negative results. Being on the low end of SG levels in aquaria, would this have occured if those readings were 1.026 with a decrease of .002? If your system was at 1.026 and had mainatined this reading for months, I don't believe you would have experienced such dramatic declines, but that's just me. It's just a hunch, what do you think? Sounds like a good discussion is continuing. I think your observation is sheds much light on the importance of SG.
I think you're sharing this is very very helpful. Thanks for sharing my friend. Hope to see more like this.
Mucho Reef
