Rising ph level?

Our tap water comes to us at a ph level of right around 9.0 with 20 ppm of tsd. I use PH Down to lower it to about 5.8 using a calibrated digital meter. I store it in an opaque, 3 gallon container, placed in the grow room. I was trying to get my plants run-off to be around 6.0, so i was checking the water before i used it. It seems to have gone up over a full point in about a week. The room has a 1,000 watt mh in it now. I was wondering if the PH Down is light sensitive? Anyone ever noticed anything like this before? It seems like the container holding the ph adjusted water and Sensi-Grow is staying alot closer to the 5.8 I set it at.:wtf:

Your water has stuff in it that affects the pH. Some of the stuff wants to push the pH down; others want to push the pH up. So you kind of have an up/down battle going on. Whatever is in your tap water is stronger than your pH down, so the pH gradually rises. This is completely normal. When you add the nutrients, they act as a strong buffer to bring the pH down, counteracting whatever is in your tap water buffering it up. That's why your nute solution is more stable than your plain water

PC :smokin:

thats realy high ph for tap, my tap is 5-6, but i also use a mh and every 2 or 3 days my ph rises about a point, i just add a little, gh ph down. but its prity mormal

Ditto with the buffer thoughts. If I was in your shoes and I thought it was a problem I would use the GH Floranova nutes. they have a built in buffer that stays at a steady 6.0 in most sittuations.
Adieu

Yup, a buffered hydro nute is a BEAUTIFUL thing. I just switched to Canna Aqua for that exact reason.

stinky, Canna Aqua all you use or mix with others? it any good?

It's excellent. I use it stand-alone for my hydro system, the 2part, and I add TopMax and molasses approximately whenever I remember to.