I am sorry Jesse, I don't check this 'my RC' very often. I am often in the macro algae topic though.
I usually keep my seahorse tank down in the lower 70s around 70-72° F. Since my sump is in the basement and the AC is set at 76° I am getting away without a chiller by running a fan over the sump 8 or so hours.
I have run a UV sterilizer in the past but when it died I have not replaced it. It will NOT help with the pathogenic bacteria that make the ponies sick since those bacterias are not water borne. They are in areas of rotting food or plant/coral debris and detritus. I am thinking of buying a new UV however to help with diatomous algae or cyano on the sandbed.
Any fish is a risk with seahorses however captive bred fish are less risky because they do not carry the pathogens from the ocean. The only sourse of CB pipefish is Ocean Rider (seahorse.com). CB mandarins, most CB gobies and CB blennies that are not aggressive algae eaters are safe, ( blennies with algae scraping teeth can damage seahorses skin if they try to rake their teeth on the seahorse.)
I am guessing that you are thinking of getting into seahorses or have already. They are not hard but are very different from other marine fish and reef tanks. It take a different mind set to keep them.