It's a new system and I am having troubles with a certain valve. I have since corrected that problem. There wasn't an extraordinary amount of debris in the system, just some pebbles in one spot. The shop vac was overkill. When I fill the system at the main shut off I do it slowly. So I don't slam it with water. Its air hammer and I can't get it out - would blowing down the system with air and then filling back up help? I guess my question is this: Could running the shop vac (suction) on a valve create a seepage in a fitting that only lets air in - underground and, if so, do I have to dig it up? How do I find that leak? etc...

Well the meter is brand new like 3 weeks old and i am not sure if i can calibrate it or if i remember correctly the documentation that came with it said i will never need calibration not 100% sure but the water level was the same as when i checked it the night before through the day when i checked the nutrients it varied from the original 3640 at the highest and the lowest it read and this was near the end of the day was around 2000 PPM i didn't get a chance to check it this morning so i am unsure of the PPM as of now i will check my battery and check to see if the meter can be calibrated and if so how do i go about calibrating it is there a solution i can get or is there a known PPM standard that i can use?

"Since I'm the electrician, I know where they are going. I'm using ICAT's of course, although they don't look very AT to me. I'm going to make sure they are well sealed to the ceiling plane, AND they are going to have boxes over them in the attic before the insulation goes in. " give me a minute to get my foot out of my mouth...LOL! if there are no holes in the housing..they are air tight. but what I find is that the cuts in the sheetrock are often oversized, so that the leakage is now at this penetration. I use a mastic tape to seal between sheetrock & housing of recessed light, then once trim kit is installed, the mastic tape seal doesn't show. by doing this additional sealing, the box over the recessed light in attic isn't necessary. after a decade & a half of testing homes for air leakage...doing the air sealing work..trying everything from ice chests to sheetrock boxes to ul rated 'hats' that go over recessed lights, I've found that the above method is the best. its a real pita to cut box to fit & seal air tight around 'legs' of recessed cans, and in a lot of cases the can is next to joist & box can't fit in between. expanding foam (aka great stuff) covers but doesn't seal leakage sites. but it expands so much...that you can't see the leakage sites anymore. over time, the foam shrinks allowing more leakage. thus the mastic tape method of sealing. I use only Hardcast brand #1402 mastic tape from hvac supply. I also use the hardcast to seal supply boxes to ceilings from inside the house. (I say ceilings..because that is the average location of ductwork in my area) hardcast will seal the same in wall, or floor applications. see attached pic to view how it looks. easier than explaining! best of luck.

Looking more closely I can see that the concrete slab's not level either...there's a huge gap in the lower corner, where they've packed underneath, so not only water but vermin and whatever could get in....sigh. Like I said, I'm tired of fixing others' mistakes.....and if I don't fix this, it's going to rot.