Why does my reservoir's PPM increase over time? How do you maintain an ideal PPM throughout your grow?

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onegallongrow

Member
I grow in DWC hydroponics. I have been finding recently that no matter the PPM that goes into my reservoir, I have to add water every so often to keep it down in the ideal range. I am very interested in why this happens, if it has something to do with nutrient quality/type, salt/nutrient build up, etc.. I remember reading somewhere that sometimes the plants suck up water and leave nutrients behind. Any experienced hydroponic grower that can shed light on this for me, feel free! I am growing with general hydroponics flora series.
Also-
Do you feed your plant with fresh ph balanced water in between weekly fills, or do you continue to feed nutrients of the same PPM until it's time to increase/decrease?

It can be a pain to have to replace nutrient water with fresh water to maintain my ideal PPM, so really curious for any feedback for those of you growing with a similar process!
 
OldMedUser

OldMedUser

Well-Known Member
Your situation seems to be like the 6th one from the bottom.

What is the ppm/ec of your pH balanced water and are you taking those ppm into account of the total? I always just topped up my tubs(s) with RO or distilled water then checked my ppm to see how much it dropped from the last top-up then add back a bit of nutes to get back to my target level or more to raise it if needed. I used AN pH Perfect 3-part nutes so never checked pH.

nutrient diagnosis ppm pH rise lower chart.jpg
 
Hollatchaboy

Hollatchaboy

Well-Known Member
onegallongrow said:
I grow in DWC hydroponics. I have been finding recently that no matter the PPM that goes into my reservoir, I have to add water every so often to keep it down in the ideal range. I am very interested in why this happens, if it has something to do with nutrient quality/type, salt/nutrient build up, etc.. I remember reading somewhere that sometimes the plants suck up water and leave nutrients behind. Any experienced hydroponic grower that can shed light on this for me, feel free! I am growing with general hydroponics flora series.
Also-
Do you feed your plant with fresh ph balanced water in between weekly fills, or do you continue to feed nutrients of the same PPM until it's time to increase/decrease?

It can be a pain to have to replace nutrient water with fresh water to maintain my ideal PPM, so really curious for any feedback for those of you growing with a similar process!
Click to expand...
It depends. If the water is evaporating, then the nutrient solution will become more concentrated, but most likely it's because the nutes are leaching out of the plant. What's the plant(s) look like?

As asked already, what's the ec of your solution? pH?
 
amneziaHaze

amneziaHaze

Well-Known Member
Vpd bad makes it slow, but usually you have a strain that doesnt eat that much.i have rhat problem now plants eat 1/10th of nutes i feed other strains.they are healthy just eat shit.now in flower they started eating more but its like 50ppm more nothing special
 
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bongboy8200

Active Member
I think others said it but what’s your pH looking like. If they are drinking the water and not up taking the nutrients the salts stay behind and raise the ppm
 
ProPheT 216

ProPheT 216

Well-Known Member
Evap is one part. More so tho your plant can drink water without taking the food up with it, it can also eat food faster than water leaving no ppm with water left. I think your solution is to high and she is trying to drink n not eat
 
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onegallongrow

Member
Thanks to all the responses. I do understand now that the PPM overall has been a bit too high this grow. Have done lots of flushing and learned lots for next grow. Just a tad overfed, still really excited for the final yield. Expecting it about 2-3 weeks away from harvest. Thank you everyone!!
 
C

cage

Well-Known Member
onegallongrow said:
I grow in DWC hydroponics. I have been finding recently that no matter the PPM that goes into my reservoir, I have to add water every so often to keep it down in the ideal range. I am very interested in why this happens, if it has something to do with nutrient quality/type, salt/nutrient build up, etc.. I remember reading somewhere that sometimes the plants suck up water and leave nutrients behind. Any experienced hydroponic grower that can shed light on this for me, feel free! I am growing with general hydroponics flora series.
Also-
Do you feed your plant with fresh ph balanced water in between weekly fills, or do you continue to feed nutrients of the same PPM until it's time to increase/decrease?

It can be a pain to have to replace nutrient water with fresh water to maintain my ideal PPM, so really curious for any feedback for those of you growing with a similar process!
Click to expand...

Also think about it like this, if you put all whacked up nutrient ratios.
At first the plant will eat some, but soon some of the nutrients might run out, while others keep accumulating.

So after water change its common to see EC drop some, as there is fresh batch of nutes that the plant has been craving for.
After it has gobbled up the specific nutrient, there is none left and ppm/EC's start to rise again.

So you can do less water changes with
1) bigger containers
2) knowing what your plant actually eats and feeding that
 
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