Hello everybody, i am new in the forum and in the arduino world generally. Sorry if my english is bad, but i do not speak english very well.
So, i know almost nothing about electronics, but i want to make a project with my cousin who knows some things more than me. We want to make some kind of a climate controller for hydroponics.
Specificly, we want to make a controller for the water in the hydroponics, that will control the ph and the tds in the water. We were thinking about connecting a ph sensor, and a tds meter, on arduino,
so the arduino can read the digital numbers from each one, and we also want to put two somekind of pumps, that would drop in the water the proper amount of ph+ or ph-, or a mix of fertilizers, each time the numbers are not these we have set as limits. For example, if we have set the ph between 7-8 and sometime it reaches 9, a little pump will drope an amount ,that we will set, of ph- in the water so it will reaches again nearly 7-8. The same thing with tds.(Again,really sorry if my english is bad. Also i do not know if what i am looking for is a pump or a dripping sytem, and i do not know if this can be made) Well my question is, if that can be made, of course, and if it can, if anyone can tell me some things about the pump or dripping system i am looking for, or send me a link, i would be really happy. Thank you very much. Sory if i made you tired. thanks again.
Well my question is, if that can be made, of course, and if it can, if anyone can tell me some things about the pump or dripping system i am looking for
Whether you need a pump or a drip system depends on a number of factors. How quickly does the pH change? What volume of water is there in the tank?
If you have a small volume of water, and the rate of change is slow, then the system can be controlled using small amounts of corrective material.
If you have a large volume of water, and the rate of change is fast, then the system can only be controlled using a large amount of corrective material.
It is the rate at which material needs to be added that will determine if a drip system or a pump system is needed.
nikos13579e:
i do not speak english very well.
Fortunatly, we only need to read your written English 
(that was a joke)
my question is, if that can be made, of course, and if it can, if anyone can tell me some things about the pump or dripping system i am looking for
As a project just about perfect for an Arduino, in particular with a small keyboard/LCD to see/adjust the limit settings.
The Arduino is just going to turn a pump or valve on/off, irrespective of the drip/pump choice.
Thank you very much. I thing the only thing i have to do now is to do a research about dripping systems or pumps, and just read a lot of things
and ''study'' on them so i can find out what i need to make the project. thanks again.
What are you planning to use to measure TDS? How do you 'correct' TDS, if it is 'incorrect'?
i do not know exactly, but i was thinking to have a digital tds meter connected with the arduino (if i can of course) working all day all time, and the arduino can read the numbers all the time.
so when it is under the limit i have set, a little pump will drop an amount in the water with the proper fertilizers and the proper amounts. now about the tds correction, it is clearly amateur thought,
but i was thinking for example, if i have a 50 liter tank, and i grow tomatoes, and the tomatoes need in 50 liter 5ml N, 6ml K etc., i will have a bottle with 20ml N, 24ml K for example, a general mix of all fertilizers in proper amounts, and each time its needed a little pump will drop some of this mix. i know it sounds stupid and each time the plants might need more N than K or other stuff, but i am just expirementing. i hope you understand what i am talking about. sorry again for the bad english.
I think you should concentrate on the monitoring side, for a while. Simply measure pH and TDS, and display the values on an LCD or using the Serial Monitor. When you have an idea how fast the values change, and how much correction is needed to get the system back in the desired range, then you can think about automating the correction(s).
Previous post that might be of interest.
zoomkat thanks for the link. PaulS i think you are right. its better that way. so i hope this will go ok. i will send about how i am i going, and for some help,xaxaxa. thanks again everybody.