Help my ph raises each time i flood

Hi,
I have a flood and drain setup thats driving me crazy each day the ph goes up by its self, this turned my plants yellow last week when i didnt check nute for 2 days and it rose to 8.6 :mad:

They made a good recovery a week later after I flushed the table and drained the nute tank, untill today I noticed they have started to go yellow again (I have been adjusting ph daily to 5.4). I checked the ph in the tank and it was on 6.4 so i adjusted it down with nitric acid to 5.4 mixed well let settle then flooded when the water returned into the tank it had moved to 6.8!!! so I adjusted settled and flooded 6.4 this time....... finally after 3 floods got it down to 6.1 and gave up. the question im trying to get an answer to is there anything in my clay balls that could drive ph up i really am confused and would be thankful of some help.



-indoor
-hydroponic flood and drain 300 ltrs clay balls 34 second flood 2 minute drain
-Anything you have added to the soil no
-Soil pH n/a
-Water source tap 7.2 ph 0.6 ec
-Age of plant 1 month
-Type of fertilizer canna aqua vega rhizotonic cannazym ec 1.6
-Rate of application 1 week
-Lighting source and distance from plant 4 x 600 digital sodium
-Temperature 23c / 23c
-% Relative humidity 40%
-Lighting schedule 12/12
-Type of ventilation your room has A/C floor vents with 800-1500 ppm co2


thankyou.

first of all how big is your res and what size table are you useing and are you useing rockwool at all. are they in veg or flower and how many times a day do yu feed and for what duration if in veg it should be 4 times a day for 20 minutes or so flower 3 tmes a day 20 minutes or so. wild fluctuations in ph could be due to useing rockwool with a small res the minimum size res i would ever use is 75 to 90 gallons much more stable and easier to control ph. clay balls will have little or no effect on you ph unless they have salt build up on them its agood idea to flush the res every 7 to 10 days dont go past two weeks.

sounds like your're burning them.....try diluting down your nutes a bit and see if it helps.

I've also had issues with hydroton raising the ph.....the other thing could also be your tap water not keeping a stable ph....so there's a few different thoughts right there. I would flush your system as well if you haven't in awhile like bondstreet says.

Quote:

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Originally Posted by bondstreet

clay balls will have little or no effect on you ph unless they have salt build up on them

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Fresh unused clay balls right out of the bag MUST be pre-soaked with pH adjusted water until the pH stabilizes. They WILL cause it to rise over the course of even a few hours until it is stabilized. This process can take a few days and should be done before living plants are introduced to the system, if you want them to stay that way.

thanks guys I think stinky hit the nail on the head as i olny washed the clay balls in tap water to lose the dust never knew you had to ph stabilize them :( The problem I have now is what to do to correct this, my girls are well rooted and i dont really wanna pull em out for a few days to stabilize ph I wouldnt know what to do with them.
any ideas how to stablize the balls in the table as they are, can I continue adjusting each day before first feed untill it stablizes?
or is there any kind of ph buffer I can get?

Well......we'll give you an 8 for effort....:D

Good quality hydro nutes should have a pH buffer. I had this exact problem the first time I loaded up my new hydro system with clay balls. It was about a week before I stabilized the pH but there were 2 problems that I hadn't considered:
-Not rinsing the balls. I used plain tap water just like you did, thinking the DUST would be the big issue.
-Using a dirt fert that was buffered in the high 6 range
My pH would spike up to almost 8 for the first couple days. The plants suffered greatly while I messed with them but there was only one casualty. It was jsut a matter of testing the res morning and evening and adding pH down until it was in the mid to high 5 range. It stabilized eventually. I also switched to canna nutrients, which I now run with just plain tap water. I'm not sure if the intention was for them to be so well suited to that... but they are, and buffer just below 6.

Weedhound LOL :D
stinky cheers so much for ya help. I will carry on morning and night till it calms down, hopefully soon if not theres always next time!

good thing for experts like stinky

hell yea

how did you make out with your problom

seems to be settling down :D was at 6.1 yesterday a rise of 0.5 in 24hrs I think it is stabilizing but the ladies have suffered a lil bit too much, but hopefully will recover within the next week or so:( and now I have discovered there are thrips! :mad:
Thanks for asking

eww thrips.
Pyrethrin bomb is a good way to kill them. You have to set off a PAIR of bombs spaced a few days apart to do it right.
thrips require soil in which to pupate and complete their life cycle- I am surprised that you have them in a hydro system. Are there soil-potted plants around?

well the mother was in soil but she has gone now so they could of came from her. I sprayed with spider mite control and it killed 95 percent of the thrips (seen loads of dead bodys) I think they are thrips because of the chlorophyll damage I can see on the lower leaves and they look like lil slim white/cream things about 1-2 mm long crawling around under the leaf.

sorry not 1-2mm long more like 0.5-1mm long

Yup, that would be thrips. I would not worry too much now that you have taken away their ability to breed. Just pick up some sort of pyrethrin based bug spray or bomb and use it until you see no more thrips. It won't be too hard now.

ok thanks stinky :thumbsup:

Wonder what is next? ew