PPM question

U

Underground

New Member
Hello, I have 13 plants running on a top drip system with a 18 Gallon resevoir (first off, is that a problem? should I have more than 18 gallons?). I bought a new meter that has Ph, PPM, and all that other stuff. My PPM was 330 yesterday, and today it is down to 320. Which means I need to add more nutrients? ( i think that means that) My plants have been veggin' for a month, and they seem like they are doing Fantastic !... but I've been reading about PPM being around 700 - 1200. Is it based by strain? I was reading that when my PPM doesnt drop everyday...that I have the correct amount of nutrients..I dont wanna add nutrients though and burn my plants...what should I do? Does anyone know of a thread on here talking about PPM, or another link concerning PPM for newbies?
 
These numbers are based on EC readings, .500 readings, TDS readings converted from EC or the common Hannah Chart:

Seedlings, Early Sprouts 100 to 250

Early Vegging 300 to 400

Full Vegetation 450 to 700

Early Blooming 750 to 950

Full Mature Blooms 1000 to 1600

(this excludes the ppm of your water)
 
PPM-EC-C.jpg
 
Thank you Roseman, I read your thread about 'topping off...RND and TDS', it was very imformative. I've decided to keep a daily journal with my PPM and Ph, (my meter cost $200, lol, I might as well use the dam thing...lol), hopefully I can figure it all out. I'll be doing a resivoir change in a few days..so I'll be able to get fresh readings on everything. I'll post a follow-up
 
You have to have a STARTING POINT.
You 1st check the ppm of the plain water so you can discount it later.

Then you add the reccommended, or suggested amount of nutes according to the label on the nutes. Then read the ppm and write it down, and subtract the ppm of the water when it was plain water.
24 hours later, make the ppm the same, adding water and nutes back.

Good luck, bro. Let me know how I can help you.
 
well, I got my PPM up to 612 the other day. I added some nutrients, and the plants responded well, no problems with them. after a full day of feedings my ph level went up from 5.7 to 6.4 and my PPM pretty much stayed exactly the same. I am about 6 days into my new resevoir change..and my plants have been drinking lots of the water. I havent been 'topping off' the resevoir like I guess I should have. Tomorrow I will do a resevoir change and get all my numbers together and have a nice starting point. Now, after this change, if I notice my plants drinking lots of the water....I should be throwing another gallon in the resevoir to top it off right? what will that do to my numbers? Should I know the PPM of the gallon of water to subtract it, along with my starting PPM of my plain water in my resevoir?
 
Underground said:
well, I got my PPM up to 612 the other day. I added some nutrients, and the plants responded well, no problems with them. after a full day of feedings my ph level went up from 5.7 to 6.4 and my PPM pretty much stayed exactly the same. I am about 6 days into my new resevoir change..and my plants have been drinking lots of the water. I havent been 'topping off' the resevoir like I guess I should have. Tomorrow I will do a resevoir change and get all my numbers together and have a nice starting point. Now, after this change, if I notice my plants drinking lots of the water....I should be throwing another gallon in the resevoir to top it off right? what will that do to my numbers? Should I know the PPM of the gallon of water to subtract it, along with my starting PPM of my plain water in my resevoir?
Click to expand...

Yeay ppm adjustment with tap water can be a pain in the butt. One of the main reasons I get my water at Wally World.

When I first started out, I would mix first before adding to res, then test res for ppm to see if I was in the area I needed to be in. Then check Ph.

So this was my process. Res. start was tap water at 500 ppm. ( i know higher n heck, we got crappy water). I have a 2 gallon res. bump it up to 600 with nutes and adjusted ph.

Next day, they drank 1/2 a gallon, PPM is at 550. So I figure they ate 50 ppm and I have to get it back up to 600. I mix a half gallon at 700 ppm and added that. That would get me pretty close to 600 ppm again in the res. (mind you, this depends on how big your res is.) I did this for about a week and the little ones didn't like the water. even when I had them on our straight tap water they didn't like it.
That is why I change to water with 0-20 ppm in it to start out with. lot less math. lol
 
Do you change your reservoir every week? I dont think you need to add nutes during the week if your changing your reservoir every week. I never do. I just top it off w/ water. That usually gets it back to about starting PPM. For Veg I like to start out low 400 PPM plus my waters natural PPM (120) Then increase my PPM by about 200 each week until I cut it off at around 1320 PPM. When I flip to 12/12 I like to start them at about 1120PPM and work my way up to 1400-1600PPM. Everyone has a little different of an approach. You may not need to back yours off any during flower but I move them to a new room and new system.
 
Thanks RM. working on it. :)

Yeap, I change my res once a week.
I check my res at least once a day.
I check for ppm, ph and water temp.
I adjust all accordingly.
Usually it was add a little bit more nutes, and lower the ph.
Ph is important cause that plant adsorbs certain nutes at
different ph levels.

As for my feeding schedule I Use Gh and
they have a feeding schedule here.

GENERAL HYDROPONICS

It tells me what my ppm should be during my grow. But I have found certain strains can't handle it and you will get nute burnt. So I usually stay 25% below the recommendation.
I tried pushing for them levels, but I got burnt every time and could only get it up to 75 % of the recommended.

I have couple of clones now that were given to me.
They were nute burnt awful bad.
I flush them for 2 weeks with just straight water
till I started to see new growth. I now have them at 500 ppm.
and am hoping I can save them.
 
Update on PPM

August 1st, I changed my resevoir, new START NUMBERS where...

18 gallons of distilled water was at 44 PPM, so all my numbers will have 44 subtracted from them

I take my readings around noon everyday

Morning PH - Adjusted PH Morning PPM -44
-------- STARTING PPM 682
Day 1 -- 6.32 -- 5.74 -- 672
Day 2 -- 6.35 -- 5.82 -- 688
Day 3 -- 6.34 -- 5.80 -- 708
Day 4 -- 6.20 -- 5.71 -- 690 (added a gallon of water on day 3 or 4)
Day 5 -- 6.27 -- 5.72 -- 713

I'm curious what information can be gathered by these numbers?

Now that I'm into my grow another week....should I be raising my PPM?
I'm about 5 weeks into vegetation.

Something else that may need to be considered, is that I started taking
some clone cuttings from these plants. Would that affect my numbers?
 
Looks good. Thats about the way my grow went also. I would push it up to 800-1000 ppm Bump it up another 100 and you should be good. Don't know if cutting clones affects ppm.

But from the numbers you are showing, I think your doing good.
 
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