Dear ageber:
That’s a big thumbs up for your plans to upgrade to a 90-gallon setup for your seahorses! Including a refugium, plus a quality protein skimmer and an ultraviolet sterilizer should create an ideal dedicated system for seahorses.
Offhand, the only other improvements I could suggest would be to be sure to "debug" your live rock to eliminate unwanted hitchhikers if live rock will be a component of your new setup, and to keep your refugium well-planted with a lush bed of macroalgae. For best results, keep the algae bed eliminated continuously 24/7 in order to stabilize your aquarium parameters. If you’re concerned that the lighting in your refuge isn’t strong enough to sustain Caulerpa, then I would suggest that you try Chaetomorpha and assorted Gracilaria macroalgae instead. Those macros don’t require strong light to thrive; and would do very well under ordinary incandescent or fluorescent olds in a simple strip reflector or standard daylight fluorescent bulbs. I would situate a nice clump of Chaetomorpha and a good growth of Gracilaria in your sump directly under the lamp, and then keep them illuminated 24 hours a day right around the clock. That will accomplish several beneficial things: for one, keeping such limited lighting on continuously will help compensate for its relatively low output. Another big advantage is that it will encourage vigorous growth of the macroalgae and harvesting some of the macros regularly regularly will export large amounts of excess nutrients from your tank. Finally, operating the lighting in your sump around-the-clock will help offset the daily fluctuations in pH, photosynthesis, dissolved oxygen/carbon dioxide, and redox levels that otherwise occur in the aquarium. Daily variances in chemical, physical and biological phenomena are a fact of life in aquaria, linked to the light and dark cycles and the diurnal rhythms of captive aquatic systems. As one example, the pH of aquarium water typically peaks after the lights have been on all day at a maximum of perhaps 8.4, only to drop to low of below 8.0 overnight. This is related to photosynthesis and the fact that zooanthellae and green plants consume CO2 and produce O2 when there is adequate light, but in essence reverse that process in the dark, consuming O2 and giving off CO2. Redox levels, available calcium and other water quality parameters are affected in similar ways. Needless to say, these variations are far greater is a small, closed-system aquarium than they are in the ocean, so it’s beneficial to minimize such fluctuations by maintaining 24-hour illumination in your sump. Voila! Just like that the roller coaster ride is over: no more daily fluctuations in pH or highs and lows in calcium levels, oxygen minima, or peaks and valleys in redox potential.
Best of luck with your plans for the new seahorse setup, ageber!
Happy Trails!
Pete Giwojna
Ocean Rider, Inc. is an Organic Hawaiian-Based Seahorse Aqua-Farm & Aquarium that Follows Strict Good Farming Practices in Raising Seahorses and Other Aquatic Life.
