Temp salinity of our tanks.. Are we way off where we should be??

[Mortie31]

Hello all
This was posted an another forum recently and I think it's a really interesting article and potentially raises several points worth considering to the very basic husbandry of our reef tanks.
http://www.ronshimek.com/salinity_temperature.html
Have we been getting the most basic parameters very wrong for a long time... discuss please

 

[Mortie31]

An interesting point made in the above article...
In 1999, Kleypas, and her coworkers, published data on coral reef temperatures (Table 1) (Kleypas, et al, 1999). They examined and summarized published data taken from separate measurements on over 1000 different coral reefs. It is worth remembering that these data were gathered prior to the recent increase in temperatures attributable to global warming and probably reflect more-or-less “normal” conditions for the last couple of centuries. The data in the average column are probably the most pertinent. The average temperature calculated for all 1000 + coral reefs was 81.7°F. Over all reefs, the average lowest temperature observed was 76.4°F, and the average highest temperature was 86.4°F. One way that these data could be interpreted would be to say that for most corals and coral reef animals, the best conditions would be between 76°F and 86°F, with the average being about 82°F.

 

[Mortie31]

Another summary from the article... food for thought

The bottom line for salinities is simple. There is simply no reason at all to maintain the salinities of our systems below normal reef conditions. All reef inhabitants will suffer damage from prolonged exposure to lowered salinities. Invertebrates kept at low salinities often die within a few days to a few months. Given that corals, sea anemones, sponges and some other invertebrates have no old age or senescence (or to put it another way, they are immortal), low salinities result in a quick death. Some mollusks, crustaceans, and most fish kept at low salinities die of kidney failure; it just takes them longer. A fish which dies in a couple of years in a hyposaline aquarium may have had the potential to live more than 20 years had the salinity been appropriate.

 

[markalot]

I keep my tank at 79 (sometimes up to 80 in the summer during the light cycle). If corals grew any faster I'm not sure I could handle it. Running at the natural average is dangerous IMO because it's nearly impossible to duplicate the slow yet strong flow of the ocean. A coral getting blasted constantly by an un-moving light source (earth rotates so corals in the wild experience light at different angles all day) risks overheating if water temps are too warm. In my non scientific opinion anyway.

I consider 82 an emergency overheat condition and shut off all lights when this happens. I'm sure there are those that run at 82F without issue, but I prefer cooler.

For me salinity should never fall below 35ppt so no argument there.

 

[Randy Holmes-Farley]

Hello all
This was posted an another forum recently and I think it's a really interesting article and potentially raises several points worth considering to the very basic husbandry of our reef tanks.
http://www.ronshimek.com/salinity_temperature.html
Have we been getting the most basic parameters very wrong for a long time... discuss please

Wrong? That's a very old article and not far off my recommendations that I've made for 20 years of 35 ppt and about 80-81 deg F.

Optimal Parameters for a Coral Reef Aquarium: By Randy Holmes-Farley
https://www.reef2reef.com/threads/o...-reef-aquarium-by-randy-holmes-farley.173563/

from it:

Salinity

There are a variety of different ways to measure and report salinity, including conductivity probes, refractometers, and hydrometers. They typically report values for specific gravity (which has no units) or salinity (in units of ppt or parts per thousand, roughly corresponding to the number of grams of dry salt in 1 kg of the water), although conductivity (in units of mS/cm, milliSiemens per centimeter) is sometimes used.

Somewhat surprisingly, aquarists do not always use units that naturally follow from their measurement technique (specific gravity for hydrometers, refractive index for refractometers, and conductivity for conductivity probes) but rather use the units interchangeably.

For reference, natural ocean water has an average salinity of about 35 ppt, corresponding to a specific gravity of about 1.0264 and a conductivity of 53 mS/cm. It often ranges from 34-36 ppt over reefs, but can be higher or lower locally for various reasons such as land run off of fresh water, or evaporation from a lagoon.

As far as I know, there is little real evidence that keeping a coral reef aquarium at anything other than natural levels is preferable. It appears to be common practice to keep marine fish, and in many cases reef aquaria, at somewhat lower than natural salinity levels. This practice stems, at least in part, from the belief that fish are less stressed at reduced salinity. I have no idea if that is true or not, but I’ve not seen evidence that it is true. Substantial misunderstandings have also arisen in the past among aquarists as to how specific gravity really relates to salinity and density, especially considering temperature effects. For example, the density of seawater is less than the specific gravity, and measurements with glass hydrometers may require temperature correction, but newer devices do not need the aquarist to make corrections. Consequently, older salinity or “specific gravity†recommendations may not actually be referring to the same measurements that aquarists make today, even if the recommended numbers have been handed down

My recommendation is to maintain salinity at a natural level. If the organisms in the aquarium are from brackish environments with lower salinity, or from the Red Sea with higher salinity, selecting something other than 35 ppt may make good sense. Otherwise, I suggest targeting a target salinity of 35 ppt (specific gravity = 1.0264; conductivity = 53 mS/cm).

Temperature

Temperature impacts reef aquarium inhabitants in a variety of ways. First and foremost, the animals' metabolic rates rise as temperature rises. They may consequently use or produce more oxygen, carbon dioxide, nutrients, calcium, and alkalinity at higher temperatures. This higher metabolic rate can also increase both their growth rate and waste production at higher temperatures.

Another important impact of temperature is on the chemical aspects of the aquarium. The solubility of dissolved gases such as oxygen and carbon dioxide, for example, change with temperature. Oxygen, in particular, can be a concern because it is less soluble at higher temperature.

So what does this imply for aquarists?

In most instances, trying to match the natural environment in a reef aquarium is a worthy goal. Temperature may, however, be a parameter that requires accounting for the practical considerations of a small closed system that might suffer a power failure and trap the organisms in a small amount of poorly aerated water, something that rarely happens on a natural reef. Looking to the ocean as a guide for setting temperatures in reef aquaria may also present complications because corals grow well in such a wide range of temperatures. The greatest variety of corals, however, are found in water whose average temperature is about 83-86° F.
During normal functioning of a reef aquarium, the oxygen level and the metabolic rate of the aquarium inhabitants are not often important issues, and many reef tanks do well with temperatures in the low to mid 80's. During a crisis such as a power failure, however, the dissolved oxygen can be rapidly used up. Lower temperatures not only allow a higher oxygen level before an emergency, but will also slow the consumption of that oxygen by slowing the metabolism of the aquarium's inhabitants. The production of ammonia as organisms begin to die may also be slower at lower temperatures. For reasons such as this, one may choose to strike a practical balance between temperatures that are too high (even if corals normally thrive in the ocean at those temperatures), and those that are too low.

These natural guidelines leave a fairly wide range of acceptable temperatures. I keep my aquarium at about 80-81° F year-round. I am actually more inclined to keep the aquarium cooler in the summer, when a power failure would most likely warm the aquarium, and higher in winter, when a power failure would most likely cool it. All things considered, I recommend temperatures in the range of 76-83° F unless there is a very clear reason to keep it outside that range.

One additional comment on temperatures: having a small temperature swing is not necessarily undesirable. While temperature stability may sound like a desirable attribute, and in some cases it may be, studies have shown that organisms that are acclimated to daily temperature swings become more able to deal with unexpected temperature excursions. So while a tank creature that normally experiences only 80° F may be very healthy, the same organism adapted to a range from 78° F to 82° F may be better able to deal with an aquarium that accidentally rises to 86° F

 

[chipmunkofdoom2]

A friend and I went snorkeling in Puerto Rico last time we were there on business. We were snorkeling on a particularly rocky beach, where there were natural pools and lagoons. We were snorkeling in one of the lagoons because it was calmer, but the tide was coming in. The relatively warm lagoon water was getting much colder as fresh seawater was breaking over the rock formations and mixing with the stagnant lagoon water. By the rock ledge, you could actually feel how much colder the waves were than the lagoon water. There was likely a salinity differential as well because these pools were isolated from the ocean at low tide. The corals seemed to have no trouble developing despite this natural occurrence, which likely takes place every tide cycle. There were small-polyped corals of virtually ever color, rock flower anemones, and brain corals the size of reclining chairs. There were juvenile French angels, green wrasse, and tiny gobies I couldn't identify. None seemed to care about the large temperature or potential salinity differential.

I think the long term success many hobbyists have had at average hobby temperatures (76*F - 80*F) and salinities (34ppt - 36ppt) really showcases how important stability is over mimicking natural reef conditions. While it's possible that precisely matching reef temperatures and salinity might lead to better growth and health, I think that would be very difficult to prove in a definitive manner. There are so many variables in a captive aquarium system that it would take a lot of research and documentation to prove that natural salinity and temperature offers a significant increase to the health and growth of aquarium inhabitants.

 

[Mortie31]

Hi Randy
I wasn't saying the article was new, only that is was posted recently, and it was the first time I had read it and I'm glad to see your own research and writing matches closely, The discussion on the other forum posters mainly poo pooed the idea and we're defending running the lower temps and salinity they always had. I will be increasing my temperature to 27deg C and maintaining my current 35.5ppt salinity... I personally think it's good for forums to be discussing these basics, which a lot seem to be getting wrong..