Originally Posted by jnlockar
The water temperature is 67F to 69F. I try to keep the PH at 5.8 to 6 but it spikes to 7 in just a few hours.
Excellent water temp.
You'll need to be able to maintain those temps throughout flower.
When you add nutrients the pH goes down. When the plants use those nutrients, the pH goes back up. The larger your reservoir size, compared to your light/plant-numbers, the slower this rise will happen. The smaller the res, the faster the change in pH.
Another issue might be too much air. lol Does the pH go back down in 20 minutes, if you turn down the amount of air you're pumping in the res?