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jharding08
03/25/2013, 11:30 PM
I does Calcium and Alk using Drews Dosers pumps hooked up to an Apex Controller. I dose Calcium during the day and Alk at night.

For my Alk, the program looks like this:

Fallback OFF
OSC 000:00/002:30/057:30 Then ON
If Time 05:00 to 21:59 Then OFF
If pH > 08.30 Then OFF

I dont know if it is a problem, but within the 2.5 minutes that the pump is on, it will turn on and off several times. I think it has to do with the pH limit, but I cant see that in my graph (pH reading is every 10 minutes).

I'm wondering if the dosing pump turning on and off so frequently will wear it out. Would it be better to not run Alk at all for the 2.5 minutes if pH is over 8.30 when the Alk progam begns?

I have the pH probe in the same sump chamber as the dosing outputs. That is probably why the pH is so sensitive. Should I move the probes to a different chamber?

Here is the graph from the Apex:
http://i36.photobucket.com/albums/e23/jharding08/Alk_pH_32513_2200_zps93bdd844.png

disc1
03/26/2013, 09:13 AM
If you plan to use pH to turn your Doser on and off then you'll need to separate the probe and the Doser outlet.

jharding08
03/26/2013, 10:30 AM
If you plan to use pH to turn your Doser on and off then you'll need to separate the probe and the Doser outlet.

I'm not using pH levels to trigger dosing of Alk, the pH levels are more like a ceiling that I use to stop dosing Alk. I dont want my pH to get over 8.40 when adding alkalinity, so I turn off dosing if it is above 8.30. I had pH around 7.9 when I started and you would see in the graph that the alk doser would come on and stay on for the entire 2.5 minutes.

I'm just wondering if on and off like in the attached graph will cause wear on the dosing pump.

disc1
03/26/2013, 10:37 AM
I'm not using pH levels to trigger dosing of Alk, the pH levels are more like a ceiling that I use to stop dosing Alk. I dont want my pH to get over 8.40 when adding alkalinity, so I turn off dosing if it is above 8.30. I had pH around 7.9 when I started and you would see in the graph that the alk doser would come on and stay on for the entire 2.5 minutes.

I'm just wondering if on and off like in the attached graph will cause wear on the dosing pump.

Maybe I wrote that wrong. What I'm trying to say is that the talk supplement will have a larger impact right at the spot where it goes into the water and then the pH will even back out as it spreads out into the water. If the probe is right there then it will keep getting a high reading and shutting down the pump. If you move the probe away then you will be able to do what you want and monitor the pH of the whole tank as opposed to the little spot where the supplement hits.

thegrun
03/26/2013, 12:41 PM
...or raise the limit to 08.40