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calculation for dosing amount to achieve a target EC or PH or PPM

Hello everyone i am a new member a sorry for the long title, first i shall explain what i am trying to achieve and why.


So i am a programmer with 5 years experience creating various environmental devices mostly for growing, including a hydroponics controller which is free for others to access and build them self's.

To that extent i started on the new version of the hydroponics controller after completing my masters due to having time spare. The devices has very accurate EC, PH, PPM - TDS, water temperature and water level - volume sensors,

with 4 peristaltic pumps and an inlet and outlet pump fully configurable in terms of setting the target EC, PH, PPM - TDS, water temperature and water level - volume, peristaltic pump mode "either EC or PH", disabling control of either the sensors, dosing times,

auto refill when low, auto drain and refill on set dates with set start dosing amounts, and many many more features and options. 


While it is very easy to create a "function" - "a piece of code" to control the water level using an inlet and outlet pump with a water proof ultrasonic senor to get the height, the same is said for the the water temperature with a temp sensor and hydro heater,

though things get far far more complex when trying to control the EC or PH and now my new version has a TDS - PPM sensor i must try to control all 3.


My old version worked on the basis of working out which of the EC or PH is most out of range of the target and just dosed a set amount of solution either PH up or down or some nutrients every dosing interval "say 4 hours", to which the dosing amount was set by the user too.

The controller had no real algorithm to calculate the exact amount of solution or nutrients or how much water to replace to decrease either, so i ask you experienced hydro users how do you calculate the amount of PH solution or nutrients when you know the

EC, PH, PPM - TDS, water temperature and water level - volume, is there a generic calculation? or is it by eye and experience?


Should i just keep with dosing a set amount until the target is achieved, focusing on the one that is most out of range, "note the user can set a 'max trys' which means if it has tried on control say the EC for 3 try's it would then focus on the next most out of range sensor"

Or can any of you provide me with a more accurate means of controlling the EC, PH, PPM ?


Sorry for such an odd post but any help is greatly appreciated, kind regards from Kawasaki.

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i dont understand your post entirely but for me when i ran NFT theres only one way to monitor PH / EC / CF /PPM........ and that was with my eyeballs / use of a truncheon and a ph meter ....good luck. :skin_up:    ooops btw im thick as fuk. lol

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Can't help with your post unfortunately but will be watching with interest. I eventually want to try and automate watering and nute top ups but a long way off that.


I am interested in monitoring the water level in my res. I currently have temps monitored by Pi so would like to add the Res measuring device. 


I'm hoping that the ultrasonics sensor you mention would do this? I guess I would just put it at the top of the Res pointing down? Is it the JSN-SR04T?



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With the system you describe would it not need calibrating at whichever place it was set up ? I say this as your base water where you are will be different to where the end user is . From what you describe it would be better to have three separate process all the time , one for temp , EC and ph . Then you still have to set it up for where it is , so how would the program adapt ? Or would it have memory functions for differnt t bases of water ?   Most big set ups have huge tanks which are constantly read by sepperate controllers .

there are dosing set ups available already , so is yours much different ? One place I worked had two auto doses for treating a cooling tower , and the circular pumps on the pipes where absolutely unreliable lol was twenty years ago mind 

Edited by Arthur Mix

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I think it is best if i show you the system i have built thus far, my new hydro control system  and the old version fully setup but its a long video more for devs old controller

In short all i need to know is, how does a pro know how much nutrients to add once you have measured the EC and PH, PPM, water temp, water volume.

Do you just do a calculated guess from experience or is there some kind of calculation?


In reply to you questions yes the system stores loads of data, the temperature and water level control is two separate tasks run individually by the device and the EC, PH is a paired task controlling both but only adjusting one of the two every x hours.

My old version had machine learning and could adapt but i am trying to rewrite the control algorithm and then i shall write a new machine learning function.

Edited by Kawasakizx10rr

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It would work only if all the nuts and water would always be the same. I find that when I fill my water tank and start setting up my pH it takes different volumes of same pH down to set the target. I will give you an example  why it cam give you some headache: on a last fill up of 80l of water it took 15ml of pH down to get from 7.2 to 6.0. and adding another 2ml dropped it below 5.5. some nuts put it up as well.

You would also need a all-in-one type of nuts as normally we use multiple products that can not be mixed together directly from the bottles-we need to add one by one and often dilute them before adding to the reservoir. 

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You prob need to sepperate the ph and EC as they will be controlling pumps to adjust . Like I say you need to calibrating where you are with just water , then work out EC levels and how ph reacts etc, with added nutes . Older growers have a rough idea of amounts to use but that's not programmable ..

Edited by Arthur Mix

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