PPM dropping when lights are off?

Darknes01

Well-Known Member
Hey guys,
had an interesting question. my plants seem to be eating most when the lights go out. is that normal?
for example today at 9am the lights went out and ppm was 850 (700 scale)
at 3pm ppm was at 710.
Lights go back on @3pm and now 1hr after the lights went on ppm dropped another 20 to 690.
it was similar situation yesterday.
oh i moved these clones into my RDWC on 1-8-
I am new so i was under the impression they would be eating during lights on period but seems like the opposite is happening for me.
thoughts?
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fragileassassin

Well-Known Member
I've seen stuff that said they will focus more on root growth during dark periods and at that stage of life, root growth is pretty much their biggest focus anyway so they can still eat plenty at night
That 850 to 710 is a bigger swing than i usually see though. Not sure what that's about.
 

Darknes01

Well-Known Member
I've seen stuff that said they will focus more on root growth during dark periods and at that stage of life, root growth is pretty much their biggest focus anyway so they can still eat plenty at night
That 850 to 710 is a bigger swing than i usually see though. Not sure what that's about.
ya something strange is going on or im over thinking it. Now @10pm the ppm is back up to 810. i dont see how they would consume over 100 ppm and then return it back to the res? lol i really dont get it
 

Darknes01

Well-Known Member
Ok, so it was the bluelab guardian giving wrong info. i gently shook the prob and today before it was showing 600 now its showing 920. im guessing something was stuck on the prob leads or something. not sure but wanted to post it incase someone has similar issue.
 

fragileassassin

Well-Known Member
Ok, so it was the bluelab guardian giving wrong info. i gently shook the prob and today before it was showing 600 now its showing 920. im guessing something was stuck on the prob leads or something. not sure but wanted to post it incase someone has similar issue.
tbh, i was wondering if you might have been getting incorrect readings somehow.
I run the same system and the heads do get gunked up fairly quickly. I move mine around the grow every few days to check different things regularly and clean them with alcohol or peroxide and rinse in fresh water before they go into a new system.
id just get a small spray bottle to keep some fresh water in and pull them out and give them a good spray out and maybe a wipe down once a week or so if you dont have a regular cleaning routine for them already.
You could possibly have a short in the wires or a sensor going bad too.
 

Darknes01

Well-Known Member
tbh, i was wondering if you might have been getting incorrect readings somehow.
I run the same system and the heads do get gunked up fairly quickly. I move mine around the grow every few days to check different things regularly and clean them with alcohol or peroxide and rinse in fresh water before they go into a new system.
id just get a small spray bottle to keep some fresh water in and pull them out and give them a good spray out and maybe a wipe down once a week or so if you dont have a regular cleaning routine for them already.
You could possibly have a short in the wires or a sensor going bad too.
well its brand new, took it out of the box 3 days ago and this happened. and after cleaning it , i checked the ec test liquid and it showed exactly on point 2.77EC , now back in the res , it showed 930 and 1hr later im at 900. ill have to wait a few days too see if that massive drop happens again or not, if it stays stable then im good but if it keeps doing that then it defeats the purpose of paying 300 dollars to keep it in the res and me having to shake it or spray it every day to get an accurate reading. I could of just bought the 150 dollar one and did a hand test daily.
 

fragileassassin

Well-Known Member
well its brand new, took it out of the box 3 days ago and this happened. and after cleaning it , i checked the ec test liquid and it showed exactly on point 2.77EC , now back in the res , it showed 930 and 1hr later im at 900. ill have to wait a few days too see if that massive drop happens again or not, if it stays stable then im good but if it keeps doing that then it defeats the purpose of paying 300 dollars to keep it in the res and me having to shake it or spray it every day to get an accurate reading. I could of just bought the 150 dollar one and did a hand test daily.
Its unfortunate, but it sounds like you might have just got a bad one from the factory. Id contact the place you got it from about getting an exchange if it keeps doing it. If thats of no help it should be covered under the manufacturer warranty.
I got mine second hand for $50 and its been rock solid for nearly 2 years.
 

Darknes01

Well-Known Member
Its unfortunate, but it sounds like you might have just got a bad one from the factory. Id contact the place you got it from about getting an exchange if it keeps doing it. If thats of no help it should be covered under the manufacturer warranty.
I got mine second hand for $50 and its been rock solid for nearly 2 years.
Do you keep your probes in the tank at all time? i got this model so i can leave the ph and ec probe submerged and just glance at it a few times a day to see how my plants are doing.
 

Darknes01

Well-Known Member
Yes, I leave them in 24/7 so I can just look down the stairs and see my readings.
does it fluctuate a during the day? like for example when i posted that it was 930 then it went down to 900 and now about 21 min after my post its down to 890. im just trying to figure out if this kind of movement is normal. also how often do u take readings? once a day or 2 times?
 

fragileassassin

Well-Known Member
does it fluctuate a during the day? like for example when i posted that it was 930 then it went down to 900 and now about 21 min after my post its down to 890. im just trying to figure out if this kind of movement is normal. also how often do u take readings? once a day or 2 times?
Fluctuations like that for me are usually over a day or two. I might drop 40-50 overnight if they're hungry, but not dropping 40 in an hour. Mine will fluctuate by 10-20 sometimes but I've always just credited that to water moving around them constantly.
Are the probes in well circulated water?
 

Darknes01

Well-Known Member
Fluctuations like that for me are usually over a day or two. I might drop 40-50 overnight if they're hungry, but not dropping 40 in an hour. Mine will fluctuate by 10-20 sometimes but I've always just credited that to water moving around them constantly.
Are the probes in well circulated water?
i think so, currently im circulating about 270 gallons per hour and here are some photos of the probe. probeintank.jpgbluelab.jpg
 

fragileassassin

Well-Known Member
That placement should be fine, I'd really consider getting it replaced or checking behind it with a cheap pen. What you've described does not sound like how mine works.
Idk if nutrients themselves can cause that kind of fluctuation, nutrient knowledge overall is an area I'm lacking in still lol
 

Darknes01

Well-Known Member
That placement should be fine, I'd really consider getting it replaced or checking behind it with a cheap pen. What you've described does not sound like how mine works.
Idk if nutrients themselves can cause that kind of fluctuation, nutrient knowledge overall is an area I'm lacking in still lol
ya i thought so too. ill give it a day or so and if it keeps doing that then its going back to where it came from lol
 

Darknes01

Well-Known Member
That placement should be fine, I'd really consider getting it replaced or checking behind it with a cheap pen. What you've described does not sound like how mine works.
Idk if nutrients themselves can cause that kind of fluctuation, nutrient knowledge overall is an area I'm lacking in still lol
I found the issue. My water pump is leaking small amount of electricity into the water and causing the EC meter to read wrong. IMG_20200122_143342.jpg
 

fragileassassin

Well-Known Member
What pump are you using for your system?
Just some cheap ebay ones. Wanting to upgrade to some nice DC pumps, but the one I need is like $100. Look at some of the DC pumps on amazon and read reviews, lots of the big aquarium guys use them and tend to give very detailed reviews about everything down to if the threads will work with pvc fittings ect.
 
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