It is a fallacy that seahorses need low flow. In fact, you can have areas of low, medium and high flow as long as you have hitching in each area so they can choose where they wish to be at any time. Some of mine like to play in the power head flow.
As long as it isn't going to blast them against something or cause them damage in any way, it should be good.
It would have to be an awful large kreisel to put adults in as the recommended tank size for most available in the hobby would be 29g for ONE pair and each ADDITIONAL pair needing an extra 15g.
For some more information on starting into the seahorse hobby, see the links at the bottom of "
My Thoughts on Seahorse Keeping"