Hi, i have 10y experience with soil, but struggling with new EBB&Flow setup..help!



I´ve grown quite successfully in soil for quite some time, but due to unexpected events, i was forced to quit my soil grow and stop for a while(couple of months).
Since then i´ve decided to try hydro and after some investigation, i went with the setup described below.
I hope some kind soul could help me tune up my grow procedures and help me with some doubts i have, since hydro is a completely different monster(at least to me).

My setup is an ebb&flow, clay balls only, with 4inch netcups and 4inch rockwool cubes and using 1\2 strength GHE nutrients schedule in first week(tap water ph:7.5+-, down to 5.5+-).

I´ve started 5 clones, that where collected with 1week flowering time, and started showing some pre flowers and pistils(while still in the humidity dome).

They´ve been on 18\6 for about a week(after rooting), 3 of them seem to have return to veg., but also show some leaf tip burn. The other two are a bit behind and a bit pale(no burned tips).

My struggles are with PH(everyday climbs to 7.4\7.6), and every day is returned to 5.5 with phdown, should i do this?!) , and ppm, i have a calibrated us/cm conductivity pen, but i have many doubts about what ppm schedule to follow, and if i´m reading it well(i believe that ppm conversion is about half of us/cm readings?!).

Must i bring down my PH everyday? Should i quit the ghe schedule and just trust my ppm readings and stick to a generic ebb&flow ppm schedule?

Help will be much appreciated.

Humble respect to you all.Peace.

Nobody !?

Well, i´ll just leave a few other questions for a while before i delete the thread...so here it goes(i feel like a nut talking to myself...).

My main question is about PPm readings, i really need to know how i should be mixing my solution using this(photo below) pen i have that reads us\cm, which(according to what i´ve read) converts to PPM in the following way.
1000us\cm=500ppm, this means that if well calibrated, a 2000us\cm(or 1999us, to be more exact)reading in the meter, translates to about 1000ppm, which i think is a bit short for the complete grow process.

How do i know the amount of each GHE flora series(grow,micro,bloom) to use and how do i mix my solution?

My understanding is that, if you have a 200ppm tap water and need to have a solution at 1400ppm, then you have to add nutrients to about 1600ppm(which i believe i cannot read). But in what amounts of each should i use, because using the GHE schedule my solution started at about 350ppp with a 2,5ml/10L of each.

Can someone please help me whit this? Thank you.

Main technical parameters:
Measuring range: 0 ~ 1999us/cm
Resolution: 1μs/cm
Accuracy: + _2% (F.S)
Power Supply: 2 * 3V (CR2032 Battery)
Automatic temperature compensation: You can automatically display the value of the value when converted to 25.
Operating temperature: 0 ~ 50
Environmental relative humidity:-+95%



Well-Known Member
to start off 200 ppm tap water is very close to being too hard. you might get some issues from that.

for me the ppms usually go as follows...newly rooted cuts 150-200 , young vegging clones 200-350 depending on strain, full on ready to flower size vegging clones 500-700 ppm, flowering really depends on your strain and how hard you want to push. some people i know ramp up as high as 1800-2000 ppm in flower. I run about 1200 in nft. Noticing in a bubble bucket im trying out that 700 ppm seems almost too much for my 1 month old vegging clone.

As far as your wild pH swings...what are your ppm doing during the same cycle? what are you using to lower pH ?


Well-Known Member
Not sure about your feeding since i use a local nutrient solution and just use ppm as my indicator. huge pH swings daily will cause problems. best to figure that out so you dont have to adjust daily


View attachment 2161169
good question max
I noticed you are using tap H2O.Has buffers in it.Will def screw with the ph.try boiling your water and let sit for a day before using it. You can also get RO water @ walmart or grocery store , about 6 $ a gal.Botanicare has a fairly simple line.they also have a nute calculater which tells ya what amounts of each one to add.This is ebb flo flood n drain tray,botanicare nutes,6weeks in flower


Active Member
i see misinfo in this thread....not pointing fingers..
i use 250-265 ppm hanna scale water
first grow i used fox farms ....huge jumps in ph....next was gh huge jumps....then dyna-gro and it will jump twice...then its cool for a week...


Well-Known Member
you will notice that i said might. babysas. to call that misinfo is somewhat disengenuous. it comes down to what is in the water. Can you grow with 200+ ppm water and have sucess? yep. can it cause problems? yep.


Well-Known Member
I'm running the same system, I also use tap water. I have great success, pm me and we will talk later. I'm at work but when I get home I will help you out big time
Did you make sure and PH the rockwool, and hydroton before using?
Well, the rockwool was ph balanced, but the not hydroton, because the guy in my grow shop told me to just wash to remove the dust, and to let it dry out a bit before using it.....i guess i should have!?

Well, something to remember next time.

Thanks for you reply(question).
As far as your wild pH swings...what are your ppm doing during the same cycle? what are you using to lower pH ?
The ppm rises a bit, but it´s negligible, probably because of evaporation.
I probaly should mention that my plants are in day 10 in the hydroton, but it took almost the first week to revert to vegging, they are only now starting to grow.

If you don´t mind i would like to make you a question.
How do i make my solution to come to a certain ppm using only the pen, if according to the GH schedule, the ratio between the grow-micro-bloom keeps changing?How do i know, how much of each do i need to put to bring my solution to 1400ppm for example?And in what ratio?

Thank you for your help.


Well-Known Member
If your using tap water and want to make sure not to have those wild pH swings, you should setup a large holding res that you can store your water in for a couple of days to let the pH settle. I find it best to do it this way when you start out so you can figure out the ratios that work for your tap water. What I have found is that I have to add so much pH down to my water to get it to the right level but the next day it is really high again. To correct this I found that I have to dose much higher and initially go lower than needed so the solution defeats the buffers to get it to the right pH. I have it down to where if I am in a hurry I just add so many mL to my res/gals and I know that tomorrow it will be a steady 5.8pH. IMO this "shooting it low" technique is what is not good for your plants while growing in tap water, otherwise it is fine.

If you use the holding res what I do is fill it up and always keep the water oxygenated, then I simply adjust the pH in the tank. I let it sit a day or two depending on how much I have added. This way I always have "ready-balanced" water ready. Also make sure to cover the res and keep the water cool, you can add frozen water bottles if needed.

Also when you adjust your PPM, I would minus about 100 to 150 PPM from what your meter reads but remember your new hydro babies need less than what you used before. I am sure you know that though since you have grown before. Also take what I say with a grain of salt because everyone has their own way. Good luck and happy growing to you!


Well-Known Member
Could be a host of things from looking at your plants, but I would try adjusting the water first as mentioned. Give them some time to recover, also maybe slow down your nutes. Looks like some of the tips are burned but it's hard to see what is really going on. Generally in hydro most people find they are over loving the plants in the beginning, I think.
Hi, thank you Kushnotbush.

Yes i do understand that they need less nutes in hydro, but this was such a radical move to me.You see i have grown in soil using only organic nutes from biobizz for years with success(some day i post some bragging photos...hehehe). But now as i explained before, i decided to try hydro and this seemed the best and easiest setup for me.

In soil i´ve always used the same tap water, and i would just add the nutes, ph´d it and never had much trouble(only a few times when i changed my strains).

So, you´r saying that i should keep a secondary reservoir of ph´d water at hand, so i can use in the next res. change?Should i just bring the ph down, and watch if it changes in the next few days, and only use it if it is stable?And when i use in the res. change, should i adjust the ph after i put in the nutes?

About the temperature, my res. water is at 29ºc, i know its to much, i will try the frozen bottles trick to see if it helps.

Thanks a lot.


Well-Known Member
Your welcome, yes I would keep the second or control res filled all the time. It makes working with tap water so much easier in hydro. In soil you don't have to worry so much because the pH in soil is naturally high. Therefore, it takes less pH down to get it right. Also the frozen water bottle trick is good if your res water temps get higher as they are in your grow room, another thing you may consider is using a cooler as a reservoir whether it be for the primary res or the secondary. This will keep temps at bay for a considerably longer amount of time. I have found the larger my control res the less I am messing with "keeping it balanced." I prefer to keep the water at 5.8pH and use so much that I am adding a few gallons or more a day. This way I have between 10 - 15 gallons on hand and ready.