Ouch. Sandyfreckles, you have been "Pool Stored". They sell you stuff and sell you stuff and you spend money and when the garbage they sell you doesn't work, they tell you it's YOUR fault and make you drain and refill. What a scam!

Luckily, you've come to the right place. Most of us are pool owners, not dealers, and have been sharing effective information for years.

Step one: Have them retest the water and GIVE YOU THE TEST RESULTS! They should have a printout, if not, write them down. We need the following test numbers, and most are in ppm--Parts Per Million.
a) FC--Free Chlorine--the good stuff that cleans your pool
b) CC -- Combined Chlorine or, more properly, Combined Chloramines--the used up chlorine that smells like a pool and irritates eyes. The goal is for this to be 0 ppm.
c) pH -- Same as high school chemistry--how acid or alkaline your water is. 1 is acid, 14 is alkaline, 7 is technically neutral but pools are effectively neutral when they are in the 7.3 to 7.8 range.
d) Total Alkalinity or T/A -- Despite its name, it's a measure of how resistant to changes in pH your pool water is. Too low means your pH will ping-pong, too high means scaling. 80ppm to 125ppm is the normal range
e) Calcium or Calcium Hardness or Total Hardness -- all the same thing. Since you said you have an inground, I'm guessing it's concrete or plaster or tile. Ca should be 200ppm to 400ppm for this. If it's vinyl lined, Ca can be ANYWHERE from 0ppm to 500ppm with no problem--Calcium in the water protects the walls from leeching calcium from the plaster or concrete--vinyl isn't affected by it.
f) CYA or Stabilizer, Conditioner, or Cyanuric Acid. --This is very important and is probably what the idiots at the pool store mean by "Chlorine Lock". There is no such thing as "Chlorine Lock". What it means is that your CYA level is so high they don't know what to do. We do. CYA is needed to prevent rapid breakdown of chlorine in sunlight (UV is hard on it). But too much slows it down so it doesn't work. The solution is more chlorine. We normally recommend levels of 30ppm to 50ppm but we can deal easily with levels up to 100ppm (what the ignoramouses at the pool store call "chlorine lock") and even beyond. The cause of it? You won't believe it! The powdered "shock" they keep selling you! It's stablized chlorine, either Di-Chlor or Tri-Chlor and it adds LOTS of CYA as it adds chlorine. Using it only makes your problem worse.

g) they'll give you lots of other numbers, like TDS (total dissolved solids), Acid Demand, Base Demand. We don't need them. If they give you a copper or iron test value, we should see that. They'll also push phosphate tests because phosphate remover is very expensive and they make lots of money on it. Don't be suckered into buying phosphate remover--it's the LAST ditch effort--we have lots of things that work that you do first. And you can always go back and buy it if you REALLY need it (one out of 1000 do, the rest are told they do).

Now, you should ONLY use bleach to chlorinate. Lots and lots of bleach. How much, I won't know till we see those test numbers--plus we need to know the volume of your pool, preferably in gallons, but cubic feet is fine.

You will also need to get your own high-quality test kit that measures this stuff. PoolSolutions.com has the best a home-owner can buy, but Leslies's on-line sells a complete kit with FAS-DPD chlorine testing that's very good. (Don't confuse DPD and FAS-DPD testing--they are not the same). We don't recommend test strips because they aren't precise and are MUCH harder to get an accurate reading from than most people realize. They are OK in an emergency, and are better than nothing, but not much.

Gotta go--my turn to take care of the baby!