Having a pump that big on a 100# sand filter will make it likely that the pump will push the sand and other debris through the filter and back into the pool--which you may not notice at first, but if you ever have to clear up a bad algae bloom (and we all have to do that at some point) it's gonna be a real bear. See if they'll either upgrade the filter or downsize the pump. If all else fails and they won't do either, then Ben or one of the equipment guys may be able to tell you how to put a valve inline to slow down the pump flow.

I would absolutely not let the pool store start up your pool. Putting the stabilizer in isn't bad, IF it's not one of the chemical blends, but I absolutely wouldn't let them put any algaecide in the pool (you're asking for foaming problems from the start!). If it were my pool, I'd just tell them not to worry about it and you'll take care of it. If they won't give you a discount for not having to start it up for you, then at least just have them leave the chems at your house and tell them you'll do it. That way you can see (and we can help advise for, or against) what goes into the pool before it gets into your water. If they install the pool during the day, you can still add the chems to it that evening and it won't be a problem.

You are going to need a good test kit. IF your local WalMart has the 6-way hth drop kit, that's a good one to start with, but we very highly recommend the K-2006 that you can find on the testkits link in my sig. At the VERY least, get the cheapie OTO (uses red and yellow drops to measure pH and chlorine) and have that on hand. No test strips!!

We'll be glad to walk you through it--I just don't want the pool store to create problems for you from the very beginning, which they'll do if they add all that stuff to your water.