I agree with this 100%. OG is the best community I have seen as far as people being willing to help.
I would also add to post your PLANS for the build/grow BEFORE you start, and especially before you spend any money.
Of course, be prepared to get lots of conflicting advice - just like you are seeing in this thread. If you do enough reading on different forums, you will discover that there are many, many, very different ‘best practices’ when it comes to growing weed. Almost as many as there are growers 
Your memory must not be any better than mine 
We went over this in detail not too long ago
@Northern_Loki found a link that explains it very well. Turns out its a common problem for pool guys.
http://www.anotherperfectpoolnews.com/wp-content/uploads/Tech_Talk/onbalance_ks_co2inwater.pdf
It most likely has to do with dissolved CO2 and carbonates in the water. This can be a problem even with water that has a very low EC/PPM. In my case, my well water is normally in the 80 PPM range, but can sometimes get up to around 200, but thats rare.
In any case, getting back to the original point, with out a decent PH meter, I would have had no clue what was wrong with my grow, or even had any clue that there was something wrong.