***THIS IS PURELY A FUN PROJECT TO SEE WHAT'S POSSIBLE. THE TRIDENT IS FAR MORE USER FRIENDLY AND WELL INTEGRATED... LIKELY CHEAPER TOO***
I've been tinkering with creating a DIY alk tester using the apex. Previous versions of coding were too complex to adapt to other systems, testing took too long, it was difficult to change desired alkalinity setpoints and just too clunky when it came to directing dosing. I believe I'm finally on the right path now. This system is using a 60ml tank sample with hourly testing at the top of the hour. The code can be adapted to other schedules or tests can be reduced with some simple override code. I spent some time extrapolating data from RHF's DIY alkalinity test article using the largest sample size(1000ml). I found a nice balance using a 60ml sample with a 1:4 acid to rodi dilution .
The test works by first draining the storage water(Step1)using a couple cheap dosers to send the water back to the tank. Midway through returning the sample, the sample dos runs a 30ml profile(S2) to clear "old" water from the sample line. Once the vial is completely dry, the dos adds a 60ml sample of tank water(S3). Next, the dos reagent head adds a 9.6ml profile of reagent(S4) to get the test 90% of the way there. S4 also turns ON the magnetic stirrer. It wont turn off until the test is done- signaled by a 4.50 or lower pH. the OSC VO name S5 is the first level of detection. if pH is 4.50 or lower during this timeframe then my lowest level alk detection VO is triggered signaling an alkalinity of 8.94 or lower. If the pH setpoint isn't reached, the system carries on with steps 6-9 which each add 0.2ml of reagent. VO's monitor these steps to determine when the final pH is reached. If the pH is reached early on, the additional titrations are skipped and the system continues on with draining the waste water and refilling the vial.
The point at which the pH Vo is triggered can be used to direct the dosing until the test starts again. The alk detection VO's stay on until S1 is on again signaling the start of a new test. This is all very new and experimental but I figured I'd let you all in on the ride. I'm certain there will be some kinks to iron out so stay tuned. Code will be included in the next post so it can be edited if there are typos or things don't work as planned.
Items required:
Neptune Systems APEX(any model)
pH probe w/ 4.00 and 7.00 calibration standards
Magnetic Stirrer
Glass vial, dosing lines, and method to hold everything in place(To be Discussed later... I could use someone with experience creatind 3d print files)
2x Cheap $12 amazon 12v dosing pumps(not necessary but it removes a lot of the complexity, avoids running the dos in multiple directions, and potential error from the sample line being submerged)
BRS 50ml/minute doser for waste water(you can use the above pump but I already had this. you can also return the waste water to the reef but I would probably avoid that with hourly testing)
Neptune Dos for sample water and reagent
0.1N(0.05M) sulphuric acid($39/4L on amazon) diluted 1:4 acid:RODI
3 available apex outlets for the stirrer, waste and return pumps. preferably relays
I've been tinkering with creating a DIY alk tester using the apex. Previous versions of coding were too complex to adapt to other systems, testing took too long, it was difficult to change desired alkalinity setpoints and just too clunky when it came to directing dosing. I believe I'm finally on the right path now. This system is using a 60ml tank sample with hourly testing at the top of the hour. The code can be adapted to other schedules or tests can be reduced with some simple override code. I spent some time extrapolating data from RHF's DIY alkalinity test article using the largest sample size(1000ml). I found a nice balance using a 60ml sample with a 1:4 acid to rodi dilution .
The test works by first draining the storage water(Step1)using a couple cheap dosers to send the water back to the tank. Midway through returning the sample, the sample dos runs a 30ml profile(S2) to clear "old" water from the sample line. Once the vial is completely dry, the dos adds a 60ml sample of tank water(S3). Next, the dos reagent head adds a 9.6ml profile of reagent(S4) to get the test 90% of the way there. S4 also turns ON the magnetic stirrer. It wont turn off until the test is done- signaled by a 4.50 or lower pH. the OSC VO name S5 is the first level of detection. if pH is 4.50 or lower during this timeframe then my lowest level alk detection VO is triggered signaling an alkalinity of 8.94 or lower. If the pH setpoint isn't reached, the system carries on with steps 6-9 which each add 0.2ml of reagent. VO's monitor these steps to determine when the final pH is reached. If the pH is reached early on, the additional titrations are skipped and the system continues on with draining the waste water and refilling the vial.
The point at which the pH Vo is triggered can be used to direct the dosing until the test starts again. The alk detection VO's stay on until S1 is on again signaling the start of a new test. This is all very new and experimental but I figured I'd let you all in on the ride. I'm certain there will be some kinks to iron out so stay tuned. Code will be included in the next post so it can be edited if there are typos or things don't work as planned.
Items required:
Neptune Systems APEX(any model)
pH probe w/ 4.00 and 7.00 calibration standards
Magnetic Stirrer
Glass vial, dosing lines, and method to hold everything in place(To be Discussed later... I could use someone with experience creatind 3d print files)
2x Cheap $12 amazon 12v dosing pumps(not necessary but it removes a lot of the complexity, avoids running the dos in multiple directions, and potential error from the sample line being submerged)
BRS 50ml/minute doser for waste water(you can use the above pump but I already had this. you can also return the waste water to the reef but I would probably avoid that with hourly testing)
Neptune Dos for sample water and reagent
0.1N(0.05M) sulphuric acid($39/4L on amazon) diluted 1:4 acid:RODI
3 available apex outlets for the stirrer, waste and return pumps. preferably relays
