HELP, someone put stuff in my pool without asking

[Plumflower]

The folks who did the finish on my pool came by to look at it and have added who know's what to my new pool. It has been filled since 4/9/14 Pebbleshhen finish and i have used this method from the start. It has been completly trouble free. Every other day i was adding 64oz of 8.25% bleach and 1x or 2x week 19oz muriatic acid. Ph was mainitain between 7.8 -8.0, when it reached 8.0 i added the acid and back down in went. I could never get it to 7.5. I figured this was part of the curing process and the kids never complained about the water and it looked clear and beautiful. TA was 110, CYA 50, FC 4, CC 0, CH 350. I came home in the late in evening and there was white powder all over the botton of the pool and with testing it this morning my FC was 0 and ph was 6.8 if that it barley registered on the quick taylor test which i do every morning. I was not expecting this and i had to hurry off to work with out much time to work on the problem. I have not heard back from the pebble installer despite my numerous calls. I am very upset about this and i don't know what to do to get my pool back in balance or even the slightest idea of what they added. HELP i don't know what to do and will i ever get the water back the way it was?
thanks

 

[freqz]

OK...step 1: Calm down. You can fix this.

step 2: Run a full set of test results and add a little bleach.

step 3: Figure out what in the heck they added.

Likely someone tried to turn your Ph down for you with dry acid. If so, that's an easy fix

 

[bridgman]

If FC went to zero and you have white powder on the bottom of the pool it's *possible* the chlorine was killing algae and you need to get more chlorine in there ASAP.

I guess alternatively they could have added the powder and it was something which (a) didn't dissolve and (b) ate your chlorine but nothing comes to mind.

Option 3 is they came over for a swim 'cause they were hot & sweaty (which would eat chlorine), then washed their tools in your pool (which would leave white powder on the bottom of the pool) but I would expect anything like that to result in higher pH not lower.