OK...ponies aren't SH, and SH aren't ponies. Sorry it's a peeve of mine.
That being said, unless you plan on keeping zots (dwarf SH/H. zosterae), you're going to need a minimum of a std. 29 gallon tank for a single pair, and 15 gals for each pair thereafter (general rule of thumb).
A HOB power filter such as an Aqua Clear is fine as far as filtration goes. If you want a bit more flow, I'd use an airline as opposed to a PH (unless you're careful, SH can get their tails amputated by un guarded PH's, and non-nano models of Korallia are the worst...I've seen it happen to peeps.
The tank temp should be 74*F max to keep the bacterial count down to a reasonable level (SH are very prone to bacterial infections). This is one of the BIGGEST MISTAKES folks make.
If you use a heater, get one with a guard on it, as SH can be badly burned if they hitch to them.
LR is fine, as are any softies, however, you don't want any corals that can sting your SH if they try to hitch to them.
I like to run live macro algae in our SH setups, as it provides hitches, a place to grow, and hunting grounds for the SH to chase the pods.
Finally, I'd get my SH from a reputable breeder such as opposed to the LFS. You should INSIST on true captive bred (CB) specimens, as these will come to you happily eating frozen mysis.
On the subject of food, you'll need access to the SH every day...they lack a true stomach, and as such can't hold food for digestion. Therefore, they need to eat daily, or even better multiple times during the day. Without food, a SH's digestive system can shut down irreversibly in as little as 4 days, deending on the SH's condition.
Don't fall for the "tank raised" stock from the LFS...they've most likely been raised in net pens in the ocean and may or may not eat frozen mysis. You should expect to pay about $60 each for true CB stock. If the LFS can't ID the SH, they likely didn't come from a breeder.
Finally, never buy SH by color...SH can and will change color at will, so that pretty yellow or red SH may end up being brown in your tank.
Just wanted you to go nto this with both eyes open.
HTH
