advice sought on ppm rise

**ZEN** · 08-01-13, 04:44 PM

Hi folks im trying to find out whats goin on in my aero system. Im onto week 5 since first pistils my ph is going from 5.4 upto 6.5 in 12hrs which I believe is good. My problem is since doing a res change on sunday my ppm has jumped up, Im adding 10L of water a day to keep my res at 50L this is what i set it to on sunday 6th Jan update 1200 hrs added full res change plus silica and H2O2 also 100ml Ace of Buds which I finally decided to tryout again ph 5.85 ppm 830 res 20.3c room 29.1c

and heres a link to my diary if more infos required https://www.thctalk.com/cannabis-foru...ROPONICS/page8

The reason im asking is i want to start using table sugar for the final 4 weeks and believe it will increase my ppm so dont want to end up burning my ladies. my ppm at the moment has risen to 1040

**ZEN** · 08-01-13, 05:18 PM

ok i took the plunge, i added 10 level tea spoons of normal everyday white sugar to some water that had stood for 24hrs let it simmer for 10 mins then cooled, adde to the rest of the 2Lt bottle of water i had ready and have added it to my res. strange thing is i expected the ppm to rise but it has infact lowered it by 40ppm probaly to do with the 2L of water rather than the sugar i think.

**B.A.BARACUS** · 08-01-13, 05:56 PM

Hi zen.. I'm not 100% on your system but a rise in ec/ppm is not what you want m8.. You want it to stay stable or drop..Also that big rise you had in 12 hours of ph tells me your feed is too high...

Somebody will be along. Soon I think and probably tell your drain your system & reset it...

Then again I could be 100% wrong lol..

**B.A.BARACUS** · 08-01-13, 06:14 PM

This is a job for woody J..

**Sonofdust** · 08-01-13, 06:17 PM

Zen;
What's the tempture of your nutes been over the last week ?

**ZEN** · 08-01-13, 06:45 PM

18c-20c most of the way thru my grow m8

**Sonofdust** · 08-01-13, 06:57 PM

18c-20c cant get any better then that..

**Dr.GreenThumb420** · 08-01-13, 07:29 PM

It's because your plants are drinking the water and leaving the nutes, which means your feed is too high. Bring down/dilute the ppm and it should stay level

**Woody J** · 09-01-13, 06:55 PM

Hi guys.
First off, I have never used an aeroponic setup but my thinking is, your roots are constantly sprayed with nutrient solution, so the EC/PPM needs to be similar to DWC/NFT or maybe a little higher since there is a lot of air in the root space.

Next, we come to why the PPM's have risen while the plant has drank a lot.
I should say there are 2 ways the PPM can rise.
One is where the plant has drank a lot of water but the EC has risen.
The other is where the setup has been topped back up with water and the EC is higher than the previous topup. I am guessing this is the situation you have here.

The guys have suggested your EC is too high, your start ppm of 830 is equivalent to an EC of 1.2, depending which meter you use. I can totally understand why they said this and I would too were it not for some reading I did a while ago about feeding, EC etc.
I will try & explain whats happening.
The best way I can explain is if you imagine the roots have their own internal EC.
Because roots take in water through the osmosis process, the water can only pass through the barriers from a higher EC to a lower EC.
So if your roots internal EC is lower than the nutrient solution EC, the plant will take in nutrients & water.
If however, the internal EC is higher than the feed EC, the opposite will happen and the plant will leech nutrients.

Thus, the way to stop this is not to lower the EC but to raise it higher than the roots internal EC.
If the PPM went up to 1040 and stayed there, keep it at that level or slightly higher and see what happens.
The PPM should drop over time...

I had a quick look at some of your diary pics and the plant looks very nice and not showing any signs of problems.
Just be aware that sometimes, trying to make the numbers read what we want can result in us doing something the plant doesnt want us to do.

Try what I suggest for a few days, just 3 or 4 should do it in aero, if the plant stops drinking or the PPM carries on going up, I am wrong, so you go the other way and drop the PPM back to maybe 770 (1.1 EC)

Hope this helps.
W

**ZEN** · 09-01-13, 08:17 PM

Thanks m8 youve made a hard topic simples will monitor situation and follow ur advice

Originally Posted by Woody J

Hi guys.
First off, I have never used an aeroponic setup but my thinking is, your roots are constantly sprayed with nutrient solution, so the EC/PPM needs to be similar to DWC/NFT or maybe a little higher since there is a lot of air in the root space.

Next, we come to why the PPM's have risen while the plant has drank a lot.
I should say there are 2 ways the PPM can rise.
One is where the plant has drank a lot of water but the EC has risen.
The other is where the setup has been topped back up with water and the EC is higher than the previous topup. I am guessing this is the situation you have here.

The guys have suggested your EC is too high, your start ppm of 830 is equivalent to an EC of 1.2, depending which meter you use. I can totally understand why they said this and I would too were it not for some reading I did a while ago about feeding, EC etc.
I will try & explain whats happening.
The best way I can explain is if you imagine the roots have their own internal EC.
Because roots take in water through the osmosis process, the water can only pass through the barriers from a higher EC to a lower EC.
So if your roots internal EC is lower than the nutrient solution EC, the plant will take in nutrients & water.
If however, the internal EC is higher than the feed EC, the opposite will happen and the plant will leech nutrients.

Thus, the way to stop this is not to lower the EC but to raise it higher than the roots internal EC.
If the PPM went up to 1040 and stayed there, keep it at that level or slightly higher and see what happens.
The PPM should drop over time...

I had a quick look at some of your diary pics and the plant looks very nice and not showing any signs of problems.
Just be aware that sometimes, trying to make the numbers read what we want can result in us doing something the plant doesnt want us to do.

Try what I suggest for a few days, just 3 or 4 should do it in aero, if the plant stops drinking or the PPM carries on going up, I am wrong, so you go the other way and drop the PPM back to maybe 770 (1.1 EC)

Hope this helps.
W