Expert Advise all around... pro mix with GH

So ive been doing this a while now and had some issues recently and reaching out to anyone who uses the same or similar grow system. As of recently i switched to an at home watering solution and its been a nightmare. Instead of hucking 30 gallons every cpl days i bought a small RO system and hooked it up after my water softener... my well is almost .8 EC on its own... yuck... I figured it would overload the RO easily on its own but i may be wrong.
Recently my plants ,typically on wks 3 and 4 of flowering, have started to show a nasty phosphorus deficiency. heavy yellowing of leaves exposed to light and late in flowering leaves closer to buds will turn purple between veins ( on all strains, these arent meant to be purple). I also experience heavy leaf loss, sped up flowering and about half the yield i used to get and alot of lost taste frankly.


My system is as follows....

1. Straight Pro Mix(Peat moss with Peralite added)/root builder pots... 5 to 10 gallon
2. General Hydroponics nutrients..Flora Series Expert Drain to Waste. I use the non hardwater Micro because of the RO.... it has about 30 ppm usually prior to adding nutes ... so it appears clean although im concerned there may be salt remaining from the softener .... is this worth concern?? I also rinse with water and micro only ,every 3rd watering...
3. temps are 68 to 80 highest when lights are on
4. humidity kept 40 to 50 percent
5. room is kept clean and pots are evacuated of water within 20 minutes of watering
6. lighting is abundant with 4 600 watts hortilux/blockbuster hoods and an LED 600 equiv. but not overdone as this room has had much success in the past...
7.Water is Ph'd to 5.9 ish usually. I let it sit for one hour prior to feeding to make sure things are balanced....is this long enough or does it continue to climb beyond that....
read about the slurry test below and youll maybe understand why i ask this....


I recently took a top to bottom soil/peat moss sample to my local garden store and they did some weird slurry test and told me my soil PH was 7.7.... which is odd because I test my out water and its always the same as the in so Im not 100% sure he was quite accurate with it unless using ph plus continue to raise Ph for longer then an hour.


Im taking any and all advise into consideration on this as you can see I have a number of questions as to what I should change and how... If you have a similar grow system or have dealt with oddly rising ph or phosphate deficiency Im open to answers. This is costing me dearly right now as well as my patients... Ill answer any additional questions as well... realistically I want to solve the issue in the timeliest and most cost effective manner. thx in advance for any help

I have a very similar grow type as you, I work off well water (terrible water as I live on an old peach farm that used 50 years of crappy fertilizer into the ground. There is also tons of heavy metals in the soil/water too). I use an counter top r.o. device (www.freedrinkingwater.com) which does a great job cleaning the water down to around 30 ppm. I have a water softener and chlorinator. I use pro-mix, add 3.75 cups of dolomite lime and perlite to each bale. I use Botanicare nutes, along with 10 ml of cal/mag per gallon.

Obviously, your problem is a pH problem. I only have to wait 10 minutes for my ph/ppm meter to adjust. I pH my nute water to 6.3-6.5, never higher or lower. So, what's your problem??????

1. What kind of pH/ppm meter are you using? Do you check for it's accuracy and adjust it regularly? Do you test the water after everything has been added? Do you ever check the run off out of the bottom of the pots for pH and ppm?

2. When is the last time you changed your r.o. filters? Is it 2 stage? 3 or 4 stage? What's the make? My r.o. filters are all changed once a year, and clean the salt/chlorine/metals/etc. well lowering it (ppm) to almost nothing. Yours should too.

3. Are you adding anything natural to the soil mix i.e. bone meal, urine, etc. that can all impact your pH. By the way, most soil test kits are crap, and don't measure accurately. You could take your soil to your local Agricultural Extension Service for testing and tell them it's a mix for your tomato plants- they will be able to tell you what the issue is and what is lacking or in surplus.

4. Is it possible the containers are mismarked? What do you use for pH up and down? What strain are you growing (sativa or indica)?

I have numerous grows on RIU detailing what I do and how I do it: here's my current one:

https://www.rollitup.org/t/positronics-blue-rhino-blueberry-x-white-rhino.865117/


Lastly, I was a hydro guy for my first 3-4 years of growing but the last 25 I have used pro-mix because it is very forgiving and is easier to have good success. Your issue is probably a simple one, once you figure out the problem. I'll be happy to help......

I use an eco Ph meter side by side with a Hanna 3 in 1... Ph , EC, and ppm .... I do balance them both with calibration solution and I typically see around a 1.0 on my in going water EC and anywhere from a 1.0 to 1.6 on the outgoing water..... sometime the outgoing water can be as low as 600 if Im doing the micro/water every 3rd watering.
I changed my RO filters in the last 2 months its a cheaper125$ model i bought at the garden store... 3 stage... my ppm is approx. 30 or lower typically
I will sometimes add Superthrive or Hi Brix depending on the plants stage but other then that nothing... and yes i Ph the water after the nutes are added
My Ph plus and minus are both made by GH and no they are labeled properly as i can see the rise and fall of Ph when i add them through my meter.

I was considering maybe purchasing a soil Ph meter and maybe taking my water meter in and having it tested just to make sure....

Calibrate your ph pen?

Soil pH meters are junk......don't waste the money.

Initially, I'm guessing it has something to do with your constant flushing of the plants. I do not flush, EVER, except the last 10-12 days of flowering when I use plain water, nothing else. Your fertilizer is all chemicals though, as opposed to my Botanicare Pure Blend which has natural, mostly organic ingredients. You should be letting your plants tell you when they need a flush, i.e. burnt leaf tips. Or monitor your runoff to see a too high ppm after a watering. I think you are washing out your nutrients with the flushes........that's my initial guess.

And, you've checked for bugs i.e. mites correct?

Since you are using G.H., you know it's a complete fertilizer so it is probably the pH is out of wack and not letting the roots absorb the nutes in the correct range . And the starting water is fine, since it's thru a r.o. device. Only other thing I can come up with at this point is light burn from the plants being too close to the bulbs???? You should also consider fertilizing properly with each watering, but maybe at a slightly reduced ppm level.

Thx SSHZ... I was curious... what is your normal flowering ppm/EC.... going in ... and what point would you flush after measuring EC coming out... what number(s) would justify a flush to you.... thx again

I NEVER check the runoff because I never had a need too......but for most that do, they flush when the ppm out is higher than the fertilized water going in.....

My ppm depends on the strain being grown. Indica's can tolerate a higher ppm than sativas. But with that being said, an average would be something like:

New starts no fertilizer since promix supplies ferts the 1st 2 weeks or so

week 3-4 in veg I seem to stay around 500 ppm

1st 2 weeks in flowering I stay with my veg fert to make sure they don't yellow to quickly from lack of Nitrogen....ppm maybe up to 800ppm.

Then each week after I raise it slightly.....some plants make it up to 1200 ppm, others (mainly kushes) I can go all the way up to 2000 ppm.

Last 2 weeks water only.

I let the plants tell me if they need more or less ppm. If the leaves lighten up, I increase. If leaf tips burn slightly, I lower it. Larger plants need more too, and smaller plants need less.

SSHZ said:

I have a very similar grow type as you, I work off well water (terrible water as I live on an old peach farm that used 50 years of crappy fertilizer into the ground. There is also tons of heavy metals in the soil/water too). I use an counter top r.o. device (www.freedrinkingwater.com) which does a great job cleaning the water down to around 30 ppm. I have a water softener and chlorinator. I use pro-mix, add 3.75 cups of dolomite lime and perlite to each bale. I use Botanicare nutes, along with 10 ml of cal/mag per gallon.

Obviously, your problem is a pH problem. I only have to wait 10 minutes for my ph/ppm meter to adjust. I pH my nute water to 6.3-6.5, never higher or lower. So, what's your problem??????

1. What kind of pH/ppm meter are you using? Do you check for it's accuracy and adjust it regularly? Do you test the water after everything has been added? Do you ever check the run off out of the bottom of the pots for pH and ppm?

2. When is the last time you changed your r.o. filters? Is it 2 stage? 3 or 4 stage? What's the make? My r.o. filters are all changed once a year, and clean the salt/chlorine/metals/etc. well lowering it (ppm) to almost nothing. Yours should too.

3. Are you adding anything natural to the soil mix i.e. bone meal, urine, etc. that can all impact your pH. By the way, most soil test kits are crap, and don't measure accurately. You could take your soil to your local Agricultural Extension Service for testing and tell them it's a mix for your tomato plants- they will be able to tell you what the issue is and what is lacking or in surplus.

4. Is it possible the containers are mismarked? What do you use for pH up and down? What strain are you growing (sativa or indica)?

I have numerous grows on RIU detailing what I do and how I do it: here's my current one:

https://www.rollitup.org/t/positronics-blue-rhino-blueberry-x-white-rhino.865117/


Lastly, I was a hydro guy for my first 3-4 years of growing but the last 25 I have used pro-mix because it is very forgiving and is easier to have good success. Your issue is probably a simple one, once you figure out the problem. I'll be happy to help......

Click to expand...

Why do you run 10 ml of ca mg? Double manafac. Dose. I’m at a new facility in pro mix

First timer here. Jumped into the grow game with using HP PRO MIX. This is far from soil if you haven’t noticed. All of my challenges have to do with not feeding at 5.8 ph - I mix my silica and let it sit for 30 mins- then cal mag, micro and so on. I know that if you do not ph, adjust, then ph adjust again your feeding ph will not be consistent.

How do you mix your Ferts ?

I use 8 GH products per feeding currently, and when my plants have flourished the most is when my PH has been dialed in down to a gnats ass. I wish you the best, this stuff is pretty incredible!