Wide PH fluctuations

Never had this problem before...ill ph down to 5.6 then 12 hrs later its at 6.1 or 6.2. Its like the water lost its buffering capabilities. It has only been 1 week since res change in a 15 gal DWC for 2 plants. Whats the deal? Iv added quite a bit of PH down for 3 days now and its the same deal.

I pumped out 4 gals and replaced it with 3 gal RO 1 gal tap...im thinking it has something to do with the salt build up so let me know.

I also used molasses...I recall another grower having the same problem that may have been to to molasses or he seems to think so.

What do I do?

The rez is almost all tap...i top off with RO. PPMS were at 1700 (250 ppm tap)
I dropped them to 1400 and PHed to 5.8

Well no one posted but I did come to the conclusion that this may be a good thing....im just not used to plants that eat as much as these ones so they put out more waste as well. Plus they are really fattening up and need lots of nutes.

I had the same problem when I started adding more nutes to my res...the ph would drop initially and then slowly climb...the more nutes the more significant I noticed both of these issues to be...you might be right about the extra waste but the ph should definately level off to a much slower climb...I can't remember how many gal is your res and how many plants you have runnin through?

Once your feeding them full strength half way through flower the climb will definately be quicker so ya might be able to freeze some and dump it in the res in the morning and make fine tuning just at night...

Let me know if ya notice this to be true cause if not it would be good to know it atleast wasn't all of my problem either...so far I'm at 6 weeks and they're not even close to a foot yet but even though I've made tons of mistakes they're still kickin

2 plants 15 gal res. Week 6 flower as well. Well my ppms jumped 250ppm in 1 day and My PH 1 point. So that would lead me to believe they are just eating allot. That an excellent idea about freezing the pH down...I would have to add it to a 2L soda with RO water to make it last more than a few ice cubes. My plants look really healthy are are beefing up noticeably. I haven't really made any mistakes I know of...I wonder if this is indirectly related to molasses? Did you add any? They must just really dig it. Ill keep adding RO water to top off....I figure buffers will only hurt me at this point, they will keep trying to raise the PH so RO seems best. Am I right on that?

I'm not sure how much RO is better than britta filtered water as I don't have a tester yet (getting one soon I've beenkicking myself for waiting this long) but I have 200ppm tap water and that made the ph climb a ton if I didn't let it sit 24 hours and even with sitting 1/4 to 3/4 a point for the first 36 hours in the res... I've found the britta almost clompletely eliminates the urge to climb even without waiting very long to drop it in...

I'll let you know what the ppm ratings are for tap, britta, nuted food once I get the tester

I'm pretty sure WeedHound had a similar experience on the climbing res too and she felt it was related to growth and waste as well

As long as your girls are looking healthy and oriented properly toward the light you should be fine although I did notice that if you are going to raise the nutes that the plant seems to like it better for much weaker doses of food more often I try just really pay attention to the fan leaves cause in hydro and aero the signs are usually fast enough so that you can atleast remember what you changed ;-)

I'll post back when I get that tester lemme know how it's goin cyc

FYI I get 80ppm from the Brita filter in the fridge and 0-5 from my RO.

if your ppms are jumping i think they need less nutes i belive