pH probe placement dilemma

Billy the Mountain

Billy the Mountain

Well-Known Member
The last step of my never-ending quest to automate is installing a pH probe and a dosing pump to regulate my reservoir pH automagically.
I'm using a standard pH probe with an adc to measure, and peristaltic pumps will add acid or base to keep the pH in a defined zone.
Everything works great in testing, but I now face the problem of how to make it permanent.

My difficulty is figuring out how to mount the pH probe. Changing water levels complicate mounting the probe in the reservoir. My current idea is to mount the probe in a small "remote" reservoir where I can keep the water level consistent for measurement. This would also have the advantage of separating the pH measurement from the dosing pumps.

How do the folks with the fancy Bluelab Guardian units or similar mount their pH probes?
 
L

Lou66

Well-Known Member
Take a block of styrofoam and make a float. Punch a hole through and punch the probe in.

Just make sure to clean and calibrate it regularly.
 
D

Delps8

Well-Known Member
Billy the Mountain said:
The last step of my never-ending quest to automate is installing a pH probe and a dosing pump to regulate my reservoir pH automagically.
I'm using a standard pH probe with an adc to measure, and peristaltic pumps will add acid or base to keep the pH in a defined zone.
Everything works great in testing, but I now face the problem of how to make it permanent.

My difficulty is figuring out how to mount the pH probe. Changing water levels complicate mounting the probe in the reservoir. My current idea is to mount the probe in a small "remote" reservoir where I can keep the water level consistent for measurement. This would also have the advantage of separating the pH measurement from the dosing pumps.

How do the folks with the fancy Bluelab Guardian units or similar mount their pH probes?
Click to expand...
I just drop them into the res, a la:

IMG_0587.jpeg

I'm not clear on why "changing water levels" would complicate things. Unless the probes face the prospect of extended periods of not being submerged, I would think they would work OK in the res. No?

Regardless, I can't imagine why putting the probes in a remote res wouldn't work fine. <gentle chiding> We're not capturing telemetry data for Space X, here, right?

Very nice that you're covering both ends of the pH issue. The Bluelab doser is "single ended" (if that's the right way to describe it). Did you buy something off the shelf or was this DIY?
 
Billy the Mountain

Billy the Mountain

Well-Known Member
Delps8 said:
I just drop them into the res, a la:

View attachment 5344721

I'm not clear on why "changing water levels" would complicate things. Unless the probes face the prospect of extended periods of not being submerged, I would think they would work OK in the res. No?

Regardless, I can't imagine why putting the probes in a remote res wouldn't work fine. <gentle chiding> We're not capturing telemetry data for Space X, here, right?

Very nice that you're covering both ends of the pH issue. The Bluelab doser is "single ended" (if that's the right way to describe it). Did you buy something off the shelf or was this DIY?
Click to expand...
I have a relatively tall trashcan reservoir, the levels change a few feet before refilling. The float idea mentioned earlier is a workable solution, but my pH probe unfortunately only has an 18" bnc cable that goes to an ADC, and then a microcontroller. I'll pay more attention to the cable length next time.

Keeping the probe in a fixed position makes wiring and mounting easier.

What I did was make a small ~ 1 quart reservoir, essentially a plastic box with the pH probe mounted from the top, the outlet a few inches up on the side. A tiny stir pump keeps a consistent water level. Once finished, I'll mount above the reservoir with the dosing pumps.

It's all off-the-shelf or Amazon components cobbled together. I like the DIY route.
 
Hollatchaboy

Hollatchaboy

Well-Known Member
My probe just sits at the bottom of the res. I have a water pump circulating the nutrient solution. Works well for me, but I don't use a doser. I let my ph range from 5.8 to 6.2.
 
D

Delps8

Well-Known Member
Billy the Mountain said:
I have a relatively tall trashcan reservoir, the levels change a few feet before refilling. The float idea mentioned earlier is a workable solution, but my pH probe unfortunately only has an 18" bnc cable that goes to an ADC, and then a microcontroller. I'll pay more attention to the cable length next time.

Keeping the probe in a fixed position makes wiring and mounting easier.

What I did was make a small ~ 1 quart reservoir, essentially a plastic box with the pH probe mounted from the top, the outlet a few inches up on the side. A tiny stir pump keeps a consistent water level. Once finished, I'll mount above the reservoir with the dosing pumps.

It's all off-the-shelf or Amazon components cobbled together. I like the DIY route.
Click to expand...
Yeh, I understand the issue. Thanks for the info.

Nice that you've got coverage at both ends. I should have looked into the DIY approach over the summer (I do a Spring grow and a Fall grow. Summer's usually too warm where I live in SoCal) but I was lazy. I did manage to snag a Bluelab doser for a good price but that's single-ended. It would be nice to cover the whole range but I guess I can cop out and say I'm saving my DIY chops to make a home grown Cannatrol.
 
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