MedGrower
That hydrodude again
Typically I change the reservoir daily and during the generative period, when the reservoir starts to have lost some 7 to 10 litre of volume, I simply just add solution to top it off. Solution strength depends on the readings ofcourse, such as if the reservoir EC has gone down, I add more stronger solution aiming to make the overall strength a bit higher and/or vice versa. Typically I haven't had issues with pH swings but it depends on the circumstances always. This can happen and it should be monitored and adjusted as it fluctuates too much.
Typically in my experience, if the pH of my reservoir fluctuates, it tends to go to low end of the pH. I'd like to share a little tip. Found an interesting way to combat that; With the topping, I simply add some potassium silicate as a first aid (just some, not too much) and some carbohydrates such as AN's carboload. Trick is to provide carbs to the nitrogen eating bacteria. Seems that this has an alkaline effect on the reservoir and it helps to counter that whatever is making the reservoir more acidic. Same time this then benefits the plant by providing it some carbohydrates in available form. What amounts should you use is up to experimentation but I'd recommend going with smaller amounts and observing.
