And, you are not the ONLY one to do so.
However, the ones like you are FEW compared to the number of hobbyists who FAIL in the attempt to do so and many seahorse lives are lost because of it. This is based on my experiences and what I've followed on the forums for 14 yrs now.
For that reason, I prefer to recommend what gives the BEST chances of success as opposed to what the few are succeeding with.
Seahorses, like people, have varying degrees of health capabilities. We humans are a wide mix of those who don't ever seem to get sick or have problems as well as the majority who have some affinity for warding off problems but in reality do succumb from time to time to life's maladies, and, others still that seem to be always sick and have problems.
When we buy seahorses we have no way to know what their status might be, so putting the last category of seahorses in that situation is almost certain to be problematic. Putting the middle class into the same situation you will probably have fewer problems but they will be there. Of course the first and healthiest ones are much more able to tolerate conditions as you describe and perhaps most of those will do OK. (no guarantee though)
Of course, you can do EVERYTHING right and STILL end up with losses sometimes.
With some luck and with good care, your standard seahorses should live in the range of 5-7 years, and some beyond that even.
Of course, these are my opinions, and rather than depend just on those, please be sure to do plenty of research to find the opinions of others who are successful keepers, keeping in mind to lean towards those who seem to share opinions with a lot of others before going the route of lesser numbers of successes, bearing in mind you won't know what your new seahorses are capable of handling.
