reef-pi :: An opensource reef tank controller based on Raspberry Pi.

[Ranjib]

@Ranjib
Did I read previously that the ph board is only going to have 2 point calibration at ph 7 and ph 10?
What does that do for anyone in freshwater who is looking at a below 7 ph?
If the logic of a 3 point calibration is too hard to implement, would it be possible to allow a choice in 2 point calibration one being ph7 and ph10 and the other choice being ph4 and ph7?
Im wondering about the accuracy in acidic conditions if the probe is calibrated for alkaline ph.

Yes,. you are right , we'll be supporting only two-point calibration. Its not because of just its hard to implement three-point calibration, I didn't find many documentation or documentation that can be generic enough for different types of probes. More, over its not clear if the proprietary three-point calibration techniques are basically two independent two-point calibrations or utilize some specific empirical coefficient. From my limited reading, my learning was one can fairly reliability use two-point calibration as long as the measurement range is within the calibration range (acidic or alkaline). The implementation I am doing for ph is not aware of the scale,. it only cares about expected and observed measurement. So, you can use ph 7 and ph 4 as calibration point and use it for freshwater tanks, or calibrate with ph7 and 10 and use it for marine tanks, or just use one point calibration. I am yet to discover the impact of this. I am approaching this systematically, currently charting the raw voltage, while taking a parallel reading using atlas probe+chip, swapping different probes (American marine and milawukee) with and without the calibration applied. I am also taking parallel readings hanna ph checker (the white electronice hand held device). I'll keep you posted. Meanwhile, if you have any suggestion, please do let us know here. It will be awesome if one of us start a thread on this in the chemistry sub forum. I am really enjoying exploring all these calibration, analog converstion, testing different probes part :-)

 

[Bigtrout]

Yes,. you are right , we'll be supporting only two-point calibration. Its not because of just its hard to implement three-point calibration, I didn't find many documentation or documentation that can be generic enough for different types of probes. More, over its not clear if the proprietary three-point calibration techniques are basically two independent two-point calibrations or utilize some specific empirical coefficient. From my limited reading, my learning was one can fairly reliability use two-point calibration as long as the measurement range is within the calibration range (acidic or alkaline). The implementation I am doing for ph is not aware of the scale,. it only cares about expected and observed measurement. So, you can use ph 7 and ph 4 as calibration point and use it for freshwater tanks, or calibrate with ph7 and 10 and use it for marine tanks, or just use one point calibration. I am yet to discover the impact of this. I am approaching this systematically, currently charting the raw voltage, while taking a parallel reading using atlas probe+chip, swapping different probes (American marine and milawukee) with and without the calibration applied. I am also taking parallel readings hanna ph checker (the white electronice hand held device). I'll keep you posted. Meanwhile, if you have any suggestion, please do let us know here. It will be awesome if one of us start a thread on this in the chemistry sub forum. I am really enjoying exploring all these calibration, analog converstion, testing different probes part :)

No problem, if one can choose 4 and 7 as the calibration points that works. The reason for the ph probe in my tank isnt to know that the ph is exactly 7.020 to the nth degree but accurate to .1 or .2 works. Id be looking at the trending as way more important, and i assume its the same in saltwater!

 

[Kremins]

I'm still looking for float switches and was wondering if they are all the same and all need resistors

I have these in two tanks for my ATOs and they work great.

https://smile.amazon.com/Anndason-P...75&s=gateway&sprefix=flloat+sw,aps,182&sr=8-5

 

[AquaRaider44]

@Ranjib any idea what causes a buzzi g or humming on the pi hat?

 

[AquaRaider44]

@Bigtrout you were right 5v and ground were shorting on the pi hat mount due to flux and solder

 

[Bigtrout]

@Bigtrout you were right 5v and ground were shorting on the pi hat mount due to flux and solder

Has the buzzing gone away now?

 

[AquaRaider44]

Has the buzzing gone away now?

That fixed the majority of it but I still think something is wrong with the buck converters. Could it have anything to do with me using a 12v 4a power supply and its only rated for 2 amps? I don't think I'm drawing that much thought. Any other suggestions? Should I return these buck converters and get 4a ones or what would you recommend.

 

[Bigtrout]

Not sure on the bucks, but reading on electronic forums leads me to believe that quality is all over the place, as some chinese makers arent even putting real lm2596 in the boards, they are using copies.

In my build I opted for real power supplies, that are ul listed and a good name. There is nothing wrong with the laptop supplies, as they are usually made well, but the buck converters are the crapshoot.

Meanwell supplies are quite reasonably priced. I used couple 5v 3a meanwells and they are quite stable. Look up my build thread. A meanwell rs-15-5 is only 7.55 on amazon. Use that for the pi and keep your laptop 12v for the relays if you bought 12v relays.

 

[Ranjib]

@Ranjib any idea what causes a buzzi g or humming on the pi hat?

Nope. This is something you have to sort out, every time you use something that we have not used or not specified in the guides, if you encounter issues... we’ll have hard time to actually reproduce it,

 

[Ranjib]

Not sure on the bucks, but reading on electronic forums leads me to believe that quality is all over the place, as some chinese makers arent even putting real lm2596 in the boards, they are using copies.

In my build I opted for real power supplies, that are ul listed and a good name. There is nothing wrong with the laptop supplies, as they are usually made well, but the buck converters are the crapshoot.

Meanwell supplies are quite reasonably priced. I used couple 5v 3a meanwells and they are quite stable. Look up my build thread. A meanwell rs-15-5 is only 7.55 on amazon. Use that for the pi and keep your laptop 12v for the relays if you bought 12v relays.

On this note, I realized I can actually use apple power supplies :-) , iwatch power adapter is 5.2v , 2.4 a. Perfect for some of my build

 

[Bigtrout]

A good source for power supplies if you like to repurpose is the local Goodwill or Salvation Army thrift store. They are usually dozens of them in a bin for a dollar or two. Bring a magnifying glass to read the labels and you would be suprised what you find.

 

[Ranjib]

No problem, if one can choose 4 and 7 as the calibration points that works. The reason for the ph probe in my tank isnt to know that the ph is exactly 7.020 to the nth degree but accurate to .1 or .2 works. Id be looking at the trending as way more important, and i assume its the same in saltwater!

Same here, mostly interested in the daily cycle and the peak/bottom readings. I am having some interesting thoughts after observing the ph cycle in details... how photo period impacts it and how stony coral growth is impacted by it

 

[Bigtrout]

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Same here, mostly interested in the daily cycle and the peak/bottom readings. I am having some interesting thoughts after observing the ph cycle in details... how photo period impacts it and how stony coral growth is impacted by it

On the freshwater planted end, plants use co2 which raises tank ph, it may be possible to play with lighting intensity and use ph to track plant response. I dont dose co2 so thats a limiting factor for growth, why throw more un needed light into the mix and invite algae when its not needed.
Ph can also be useful for tracking when water changes would be helpful. If it starts swinging wildly, the little bit of KH hardness in my tank has been used up, time for a water change!

 

[AquaRaider44]

What does the error "Failed to initialize i2c. Error:open /dev/i2c-1: no such file or directory" mean?

 

[DirtDiggler2823]

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On the freshwater planted end, plants use co2 which raises tank ph, it may be possible to play with lighting intensity and use ph to track plant response. I dont dose co2 so thats a limiting factor for growth, why throw more un needed light into the mix and invite algae when its not needed.
Ph can also be useful for tracking when water changes would be helpful. If it starts swinging wildly, the little bit of KH hardness in my tank has been used up, time for a water change!

CO2 is acidic and lowers pH. Overdosing CO2 results in a pH crash, which nukes your fish. Ask me how I know :(:oops:;Blackeye;Dead

 

[Bigtrout]

CO2 is acidic and lowers pH. Overdosing CO2 results in a pH crash, which nukes your fish. Ask me how I know :(:oops:;Blackeye;Dead

Correct, but with me NOT dosing, plants using up all the co2 will make ph rise which can also be bad, it can spike quick in soft water.

 

[DirtDiggler2823]

Correct, but with me NOT dosing, plants using up all the co2 will make ph rise which can also be bad, it can spike quick in soft water.

Ah, yes. The plants will convert the CO2 into O2, but you think they'll do it fast enough to cause a spike? I've never imagined that. Hardening the water will stabilize the pH though and keep it from wildly swinging. I am very curious about how quickly the plants convert the CO2, as I have a planted tank as well.

 

[Ranjib]

What does the error "Failed to initialize i2c. Error:eek:pen /dev/i2c-1: no such file or directory" mean?

Have you enabled i2c? Please follow the adafruit first guide , end to end and update on your build thread

 

[Bigtrout]

Ah, yes. The plants will convert the CO2 into O2, but you think they'll do it fast enough to cause a spike? I've never imagined that. Hardening the water will stabilize the pH though and keep it from wildly swinging. I am very curious about how quickly the plants convert the CO2, as I have a planted tank as well.

Yes they can make it spike, growing fast with good light...but easily fixed...drop light intensity!
Hardening with kh is ok, except when you keep angels and tetras...who thrive in softer water...its a balance
My water comes out of the tap...very mildly buffered...when some plants run out of co2, they CAN use the buffer instead...vallisneria can use hardness instead of co2 when needed..so ph monitoring can tell me optimimum light intensity...and give me clues as to when to do water changes if the buffer gets used up.
I dont believe in adding chemicals to change water parameters...its expensive to fight your water. My old planted was live bearers and alkaline loving plants because my water was ph 7.6 and very hard out of the tap.
My current tank is tetras and softer water fish, because my water is ph 7.0 and kh between 3 and 5 from the tap. If water parameters go whacky...change the water its cheaper than fighting with chemicals

 

[DirtDiggler2823]

Yes they can make it spike, growing fast with good light...but easily fixed...drop light intensity!
Hardening with kh is ok, except when you keep angels and tetras...who thrive in softer water...its a balance
My water comes out of the tap...very mildly buffered...when some plants run out of co2, they CAN use the buffer instead...vallisneria can use hardness instead of co2 when needed..so ph monitoring can tell me optimimum light intensity...and give me clues as to when to do water changes if the buffer gets used up.
I dont believe in adding chemicals to change water parameters...its expensive to fight your water. My old planted was live bearers and alkaline loving plants because my water was ph 7.6 and very hard out of the tap.
My current tank is tetras and softer water fish, because my water is ph 7.0 and kh between 3 and 5 from the tap. If water parameters go whacky...change the water its cheaper than fighting with chemicals

All I use is tap water, prime as a dechlorinator, and sometimes some ferts.