What to start my PPM at after I change my reservior?

Hello there everyone,

This is my first post within the medical marijuana forums so I'm pretty stoked to hear what anyone responds with since this is only Colorado (the best)

Anyways here is my issue:

System running: Ebb and Flow
Water: Tap Water - 110 ppm out of faucet
Lighting: 5K of lighting
Humidity: 25-35%
Temp: 63-78 depending on lights out or light on
Nutes: GH (Flora series - only the 3 part series)
Medium: Coco Substrate - 45%, Hyrdoton pebbles - 55%
Strain: Denver Diesel
Altitude: Really high up here lol
Plant Growth Period: Last week of Vegging, Week 4


I change the reservoir once a week and have figured out my girls are finally starting to really uptake their nutes but I am unsure of best practice when it comes to changing the reservoir and reapplication of the nutes. Should I start low again and work my way up by about 50 ppms every day or twice a day? Or is it ok to run the 800 ppm that they were getting right before I changed the reservoir. Keep in mind also that the ppm was dropping every couple of hours from where they were eating so much (before the reservoir change).

I would really appreciate the quick response, thanks guys.

welcome! i'm a soil guy, but have a lil hydro exp as well. others will chime in too I'm sure

first thought is the water situation: straight tap water? no filtering? do you know about chlorine/chloromine?

when I ran hydro, i changed res every 10-14days religously. refill gets a boost of PPMs by 100-150 each week (maintained steady on a daily basis, usually needing 1-2 boosts a day. an automated fertigator can do this for you too and auto adjust the PH, but they cost $$$) depending on week they are in and how big the actual plant/root mass is.

I only change my res once a month (35 gal res) and get my ppms up to around 1250, but it really depends on what nutes you're using.


Edit: I see you're using GH 3 part, with your faucet PPM you can easily start out at around 1100 PPM as a base.

So lets just say I changed the reservoir where the girls were loving 750 etc then I ran a day of only water to flush out the excess salt which I have found to be an issue. Today I added 830 ppm to start and after flooding once I looked at the ppm again and it stated 870, so it appears to be sucking more water in than nutes at this point. Should I ditch half the reservoir water and start at like 400 again and work up to like 750?

Also someone mentioned the tap water and I wanted to say yes I agree I should be using ROed water but alas funds are low for this grow and I would like to purchase one after this cropout.

I wouldnt put to much into it going from 830 to 870 after the first flood, how big is your res?

Also, your tap water of 110 isnt really that bad but RO always is better, but then you need to add Cal-Mag if you're going to use RO.

My res is sitting at 35 gallons at this point and for some reason don't know if this is an issue or not but my res and pump box are continually recycling. The pump box is not filling up at all but its like the reservoir is taking the water and throwing it into the pump box and the pump box is throwing it back immediately into the res...is that correct?

I ask because when I fill the res to only say 25 gallons the res and pump box do not continually recycle at least when its not flooding time.

Is this comparable to what you have?

That is pretty much deadon but my pump controller is slightly smaller and looks like this

RO isn't really necessary as stated. just a good Tall Boy that filters the chlorine and heavies out. Looks like BD has ya covered better then I can on the other parts

My guess is if you have water continually circulating when you fill it with 35 gallon and not 25 gallon is most likely due from your hose going from your large res to your controller is siphoning water after the pump is shut off which is raising the level of the float switches in your controller causing it to pump back into your res, because I believe with those units its impossible to have both pumps running at the same time, does any of that make sense?

Yes it does make sense, sounds like a fundamental flow, should I shorten my tubing from the res to pump box or just only fill up to 25 gallons from now on?

Meant to say "fundamental flaw*"

And pressure head has a lot to do with it. I have a 12 bucket dwc and only 10 liters per bucket and the system bucket plus the pipes = 134 liters.

I'm out to buy a bigger pump now, because with only a few inches of pressure head above main pump, (unlike with my testing, alas), it has a very hard time pumping to the back of the snake line thru 18 feet of 1/2" line.

See my journal for more description. I have found, since I'm using a 9 week, clone to finsh/HPS only, I can split my feeding into 3 separate cycles and change the res water just 3 times every 3 weeks.

So then is that whats happening? I'm assuming it is because I've had that problem with every one I've set up. What I have to do is cut a small hole in the tube (the one going from your res to the controller) right before it leaves the res, that will prevent any siphoning from happening. And even though you havent seen it happen with having 25 gallon it most likely will happen eventually.

So when you say right before it leaves the res I'm guessing your talking about the portion of the tubing that isn't in the water but still within the res?

Exactly. I notice they started adding this on the newer versions, if you go here http://www.hydroponics.net/productdocs/MultiFlowControllerTesting.pdf and look at the image at the bottom of page 4 you'll notice how they do it.

Nice, I see what you mean. Not really sure how to duplicate that exactly but im sure a small hole where you were referring (the tube right before it leaves the inside of the res). I have also noticed the tubing that is within the res but brings water in leaks a bit a the top where its connected and it appears that's where someone has poked a hole for it too.

Ahhhh.....maybe that tube was originally meant to be used to go from the res to the controller?

The system has been used before and I bought it used, so I'm kind of figuring little things with the system as I go along. I did read though how pretty much both tubes need a siphon at some point, so I am going to poke a small hole in the tube you referred to and then respond back with my results.

davwanemo2 said:

The system has been used before and I bought it used, so I'm kind of figuring little things with the system as I go along. I did read though how pretty much both tubes need a siphon at some point, so I am going to poke a small hole in the tube you referred to and then respond back with my results.

Click to expand...

Hey guys,

Thank you Badboy I poked a hole in that part of the tubing for the out pump and it works perfectly now, the water is no longer recirculating, really appreciate the quick and helpful responses.

P.S. aren't you guys kind of sketched to put your pics on here? For fear of them being traced?