Flood and Drain Rez Issues

[Moses249]

I have a 4k flower room with 2 4x8 tables in it with plants in hydroton on each table. Every day I test and record the ppm and ph of my res, then top the rezz off with fresh R.O. water then test and record the ppm and ph of the rez. My issue is that my rezz seems to rise in PPM between top offs. Ill test the rezz and it'll be 5.5 1150 after I have topped it off, then ill go back in 24 hours later and the rez will have much less water and ill test it and it'll be 5.5 1220. I have heard that this means that the plants aren't feeding since salts are being washed back into the rezz, and that would mean that i should drop the PPM level lower. However, I have done this in the past running the ppm around 800-900 and still have had them ppm in the rezz rise between filling. Should i be worried about this rise in ppm? Or is it most likely caused by evoparation and plant use? Should i be running lower ppm in general? I've been using the lucas formula plus cal-mag and shooting from 1150-1330 ppm for most of flower. Thanks

 

[jyip]

My issue is that my rezz seems to rise in PPM between top offs. Ill test the rezz and it'll be 5.5 1150 after I have topped it off, then ill go back in 24 hours later and the rez will have much less water and ill test it and it'll be 5.5 1220.

IMO i think it is just fluctuation of ppm in your rez....

i am guessing you hav a something to measure your ppms with....

try this out

when you refill your rez and start fresh measure your ppm's BEFORE you flood your table/tray.... then measure your ppm's after the tray/table is flooded once..... From these two readings you will know how much your plants have taken in nutrient wise by subtracting the diference between the before & after of flooding the tray/table,,, and you will ALSO know HOW thristy they are from the amount of water that is gone after a single flood of the tray....
hope that makes sense to you,,,, its simple really...

and here is why your ppms are rising after you refill or top-off the rez...you plants are taking in the water, BUT not the nutrients, so you end up with a more concentrated blend of nutes due to this feeding & drinking that your plants have done...make sense now??? if they drink water and leave the nutes you end up witha stronger mix in your rez....when I top-off, I never add nutes, only water,, but that is me

hope this helps you

 

[hiboy]

You got no reasons for alarm
ppm usually rises between your weekly rez changing.
if your plants arent curling then ur ppms are fine
h

 

[j wizzle]

ppms rise as the plants are drinking water....think about it.

PPMs are a ratio of minerals in your water. as the water is taken up by the plant but not all the minerals are so the ratio is going to increase and you PPMs are going to rise. its normal and nothing to worry about.


your PPM levels are fine too. 1200 ppms isnt going to hurt anything

 

[Steel Erection]

Whats your ph doing? Is the ph staying stable or is it rising and falling. If its falling your mix is too strong. If its rising the plants want more. I run a very similar system. I run a 65 gallon rez. I change out the rez on saturday night flush overnight with h202 and ph corrected water 5.8. Sunday morning add my nutes and do a final ph sunday night. I do not top my rez off at all. My ph stays very stable once I figured out how much to mix. At the end of the week the rez is about half full. I learned this procedure from a respected member here and its been working very well. The only time I pay attention to the ppm is when I mix. I record my base ppm, the ppm of my additives and the total ppm. The reason I do this is so I can keep bumping the plants 100 ppm on the base every week. I've been doing this until I see a slight burn, then dial it back a little. Like I said my ph has been staying very stable this way. Just finished my second run like this and my yield increased dramatically. I dont have it totally dialed but I think once I do; I think I will yield more with less plants. Hope this helps.-SE

 

[greenmaninto]

if youre using RO, you'll probably need to add cal-mag

 

[theTinker]

Whats your ph doing? Is the ph staying stable or is it rising and falling. If its falling your mix is too strong. If its rising the plants want more. I run a very similar system. I run a 65 gallon rez. I change out the rez on saturday night flush overnight with h202 and ph corrected water 5.8. Sunday morning add my nutes and do a final ph sunday night. I do not top my rez off at all. My ph stays very stable once I figured out how much to mix. At the end of the week the rez is about half full. I learned this procedure from a respected member here and its been working very well. The only time I pay attention to the ppm is when I mix. I record my base ppm, the ppm of my additives and the total ppm. The reason I do this is so I can keep bumping the plants 100 ppm on the base every week. I've been doing this until I see a slight burn, then dial it back a little. Like I said my ph has been staying very stable this way. Just finished my second run like this and my yield increased dramatically. I dont have it totally dialed but I think once I do; I think I will yield more with less plants. Hope this helps.-SE

Can you explain this PH system ur doing more?
I think i might understand it,
PH going down: Plants are drinking more water than nutes, so left over nutes are making it drift downwards?
PH going up: opposite, more nutes, less water is being used.

Do you have any idea why a nute res would drift over a few days if not being used by plants. Eg: i top feed from res and dont recirculate.

 

[Steel Erection]

Yes that's the way it was explained to me. Too heavy of a feed ph drifts down, too light of a feed it drifts up. I run flood and drain. But there are multiples of reasons why your ph would change over a few day without an unloaded table. The first thing that comes to my mind are the ph buffers in the nutrients. If you mix a res say saturday night and check your ph sunday morning or afternoon I would bet that the ph would be different due to allowing the ph buffers contained in the nutrients having time to work. May be you have a little algae in you table making the ph change. I'm no expert but I have a feeling that topping off your res's with ro would definitely have an effect on your ph. Like I said I do not top off and very rarely do I have to adjust my ph from Sunday to Saturday night my ph usually stays very stable if I'm feeding correctly. Hope this helps you bro. Maybe keep a journal of the correlation between your ppm and ph.-SE