Steps to Completion:
How are you going to know where youre going w/o a plan? I cant emphasize enough how important it is to study up, gather data, other folks input before starting actual purchase of gear with coldwater systems. IF your tank is not matched to the chiller, filtration, circulation, lighting you will fail. So, the place to start is what do you either want to keep species wise, or display/theme-wise and next, what do you want to do with them/it?
Gear/Set up: Chillin
Lets first talk about chillers: All cool to cold water set ups require a chilling mechanism. Even the largest volumes will drift too much thermally w/o a thermostatically controlled device to keep your water about the right temperature. For the majority of set-ups commercial chillers resemble and operate something like a home refrigerator, with a compressing pump pressurizing a coolant to make it convert from a gas to a liquid, an area allowing for expansion and hence cooling, and some heat exchanger providing for this loss of energy to transfer to the circulated system water itself. The last can include drop in coils that are inserted in tie-in sumps for the most part. And it should be briefly mentioned that there are other types of coolers, cooling that is employed at time, including ground/earth and other heat exchanger technology, as well as more technical gear. These other means are for either very large or quite small (a few tens of gallons) systems.
Selecting a chiller is a straightforward proposition. Happily, in the age of the internet there are quite a few dependable websites and bulletin boards where you can query other actual users which makes, models theyve found to be of good use (reasonable purchase and operational cost, longevity); and all such manufacturers have readily available selection charts, often on the Net as well, that can be assessed to determine what size (in fractional/horsepower) youll need considering volume of the system and draw-down (the difference between likely highest ambient temperature and your desired system/tank water temperature). In actually picking out a chiller size, I encourage folks to get the next one up to give them a bit of operational margin, as well as provide for the very real possibility of their upgrading to a bigger volume system in future.
Your chiller needs careful placement. Like your home fridge, the heat-dissipating coils of the unit need to be periodically vacuumed to remove accumulating dust, and some space needs to be left about the unit for air-circulation and the occasional need to perhaps get in around it, maybe even remove it for servicing. Do make sure and place the chiller near an electrical outlet w/ sufficient spare amperage, and be aware that some units produce noticeable sound when operating.
To save money and discount condensation, either your tank should be especially thick-walled, or insulated. Early commercially made chilled aquatic systems incorporated a double-paned viewing (front) panel with a sealed in air space and purposeful desiccant (Calcium Chloride in some cases) to absorb the water vapor twixt the panels during construction. If you use just a stock set of specifications (strength only) you may well be disappointed in how easily moisture builds up on the outside panels, obscuring the view, wetting the surfaces underneath, and perhaps most disturbing, driving up your electrical bills from over-running your chiller.
A regular tank can and should be insulated, and the top covered to prevent thermal leaking. A simple approach for the sides, back and bottom is to use a glue to attach cut sheeting of Styrofoam. These supplies are easily sourced at large hardware stores. Similarly, any sump/refugium employed should be covered. You may be fortunate to have relatively low humidity in your area much of the time, but if you find theres too much, too often a coating of condensation on the front viewing panel, siliconing in another in front of it/ with a small layer of CaCl2 at the bottom space may be worthwhile.
Filtering coldwater systems should encompass brisk water movement, complete circulation, and a good deal of mechanical (particulate) screening. Ive kept large systems with just multiple hang on power filters, w/ and w/o skimmers, and using or not, any chemical filtrant/s whatsoever. Remember, the key with these systems is keeping them cold, not-overfeeding (which again is reduced with the temperature), and relying on good-sized water changes as the primary means of keeping water quality stable and optimized. Some commercial designs have utilized pressurized filter modules, but I really dont like these for the amount of labor involved keeping them clean, and the power/cost of running the pumps to squeeze the water through their media.
Illuminating these systems does not need to be a major production like tropical reef systems. Better to utilize some sort of middle of the road boosted fluorescent technology than anything else that produces too much waste heat like metal halide, unless your system is more than a couple feet in water depth. A good idea to use timers to regulate photoperiod, and its fine to leave the lights on ten-twelve hours a day, given regularity.
Many hobbyists, and even institutions located on the beach utilize synthetic water, vs. natural. They do this for convenience, greater longevity/use of the man-made product, and to reduce the likelihood of introducing unwanted critters, pathogens and pollutants. Alternatively, there are vendors of filtered natural seawater some that will deliver to your site, and places where folks can easily drive up and fill their containers with (sand/physical) filtered seawater for free. IF you opt for this latter approach, I STRONGLY encourage you to adopt a strict protocol of pre-treatment and storage of the water ahead of use. Some folks just place it in the dark for a couple weeks, decanting the water, leaving whatever mulm on the bottom to discard. Others utilize chlorine/bleach as a biocide, removing this a few days later w/ dechlorinator to assure they exclude unwanted biota.
Amongst the challenges/joys of development as an aquarist is the exploration of different types of systems, biotopes and the life that can be kept in them. Coldwater systems should definitely be experienced; for their beauty, grace and potential learning. IF you live along a cool/er water coast, DO consider checking them out.
Stocking Pacific Coldwater Tanks:
There is some good to great news re stocking these systems and some not so great. The positive is that you can really load them up with life compared w/ tropical tanks. This greater latitude is due to reduced metabolic rates from depressed ambient temperature, as well as enhanced gas solubility in such settings. The negative mentioned is a matter of availability. There are a few specialty collectors (Quality Marine is an L.A. wholesaler who deals with these a bit) who provide wild-caught algae, invertebrates and fishes from the U.S. west coast. Hence, for the most part, folks are limited to what either they can collect (not hard to do w/ some minimal gear and licensing) or have other friends/aquarists/fishers gather for them.
This being stated, Ill give you a glimpse of what is here, has been proven of use:
Stocking is done as with any captive aquatic system; with preparation and testing to assure nitrogen cycling is complete, in steps not to overwhelm beneficial microbial populations. I start new systems near the high temperature-wise that Ill be keeping them to promote the process, and place some live rock (often with all organisms intact rather than removing macroalgae et al.) in three or four every two-three week interval steps to allow for die-off and large water change effects. The break in and livestocking steps entail a few months time; definitely more than warmer water set-ups, due to the reduced chemical/biological activity of lower temperature.
Sidebar: About the Catalina Goby:
Though too often sold as a tropical or even cool-water species, the Catalina Goby is decidedly cold water (50s to low 60s F.) species; living a much shortened, tenuous period if kept in warmer water.
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