HPS Lights adjusting Ph????

We replaced our lights from a T5 to HPS and we've had major alterations with our ph and ppm. With the T5 the ph and ppm remained consistant. We would go for days with the same ph and the ppm alternating at the 1320-1290 range throughout the day. Since the exchange of light to HPS, we are adjusting ph two to three times a day to lower it to the 5.2-6 level. Our water is being absorbed more rapidly due to the heat. Because these issues didn't exist before, we are pretty sure it is the light exchange. Plant remains healthy due to our constant adjustments. In our budding cycle. Anyone got any other ideas??? Is it normal for a plant to be this high maintenance with HPS?

Some info: Use Ebb and flow with Flora/Micro, Gro, and Bloom (10 gal)
change water every Sunday.
400 watt HPS light

The Ph & PPm will change as the plant uses up different nutrients at different stages of the life cycle. The plant will put back some used up nutrients as well and that changes your PPM. If you are doing a change every 7 day's then you should just add RO adjusted water around day 4 of 7 and bring the res back to normal. You should be adding back nutrients. I only change mine every 10 day's and I flush for 2 day's between changes too.

You should expect that, what are you using for Ph up & down?

Your plants drinking more water is a good thing, mine drink up to a gallon or more each day sometimes. You did not say what the temperature was?

using GH down. The temperature has settled at 82 during the day. We put her to sleep at night, but can estimate the temp being 77-79. The ppm has settled down now, but the ph remains unpredictable. Adjusting couple, to few, times a day now. Before the light exchange, we were adjusting at once to twice within a seven day period. It just seems so odd that the ph would adjust so much. She's doing great, but we are hostages within the home to her rule! She demands constant watch and attention with the water being so unpredictable. :confused:

You're doing everything right. I've had a few that were like that; can you check your roots? The buffers in the nutrients should be able to control the swing. You can run the gambit and start checking the separate run off from each plant. That's what I do first when this happens to me. There could be some slim somewhere in the grow medium for example. You're not using rock wool are you? The only time I had that problem was when there was one plant that had slim on the roots around the ball so the long roots did not show. The only other time was when I was still using rock wool.

It came highly recommended. If you don't mind me enquiring, what do you use that is getting better results? We've debated different growing mediums, but are unsure of what works. The plant is 32 inches and budding out pretty good now. Is there a chance she has slime in the rockwool? Also, in my ignorance, what is a gambit?

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Originally Posted by hippieshaven

Is there a chance she has slime in the rockwool? Also, in my ignorance, what is a gambit?

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Yes Rockwool could be the problem catch run off from each pot and test it separately. Run the gambit is old slang for doing a series of events in order is all. Rockwool holds water in for days. If you use Rockwool and water it every 4-6 hours then only the Rockwool is getting to much water. Try burying a piece of Rockwool in your grow rocks and after 24 hours check it and you will see how wet it is and how much water it holds in.

Well my personal preference is lava rock but most people use grow rocks. I only prefer lava rocks so my trees have something bigger to attach to and not top over. 90% of the grows use straight grow rocks and plant straight to medium. I quit using Rockwool many years ago I always had problems with Ph shift when I used it no more Rockwool no more problems. As for cloning I only use an Aero-Cloner.

We transplanted two flowering females today into straight grow rock. Hopefully these two will be more balanced ph wise. Thanks for the advise and hopefully they'll have less issues.

Zan, I took some images of one of our new girls using no medium and the original we've been speaking of so. She started to fill out, she's taking her time and requiring lots of TLC, not to mention patience. I haven't began cloning yet, but I know that we should start the process pretty soon. Thanks for all of your advice and can't wait to read any feedback you have on my pics. Also, do you have any idea of what strain this is? Didn't want to use expensive seed for first female.