Ideas for measuring actual flow from DOS for continuous water change failures?

[Zinda]

Now that Neptune has a quiet DOS system, I'm reinvestigating doing continuous water changes throughout the week. I have a tank of saltwater that supplies one DOS head to add water to the tank and I have the other DOS head pumping water from the tank straight into a sink drain. They work at the same time, at the same rate.

Right now, I run the pump as fast as possible on the weekend with the ATO turned off. At the end, I can tell by the water level if one or the other pump is not working right.

If I switch this to do tiny water changes all day long, the problem I see is that:
- If the pump putting in water stops or gets clogged, it could be hidden by the ATO system "topping things off". However, I should be able to see/measure the salt water level in the salt water tank to get a rough warning that something is going on
- If the pump pulling tank water out stops or gets clogged, it could be hidden by tank evaporation

I'm failing to come up with a good way to be notified if the dirty water pump isn't working since it doesn't go to a tank (so it can't be measured).

PH will surely indicate the failure eventually and that seems like one way to detect this, but it appears as though PH meters are expensive, somewhat unreliable and hard to calibrate?

I haven't found any kind of detector that can measure flow in a 1/4" pipe, especially really low flow.

Any ideas?

 

[Jason_MrFrags]

I haven't found any flow meter for 1/4 that is useful for more than knowing if its running. Best bet would be to set them up with the dos and then Calibrate them and check every month. If you have the salinity probe make sure that is calibrated and use it as the backup to make sure things don't get too far out of wack. Once its running checking tank salinity every day/week to give your self confidence that its working properly.

 

[ca1ore]

Not sure I follow your pH point. Apex comes with a pH probe. Do you mean salinity? I do send old water to a holding tank so that when the new water reservoir is depleted, I can eyeball that the old water reservoir is full.

Absent that, you could monitor the frequency of your ATO to give you some sense that the AWS is amiss.

 

[Zinda]

Not sure I follow your pH point. Apex comes with a pH probe. Do you mean salinity?

Oops! Yeah, I meant salinity.

Yeah, if I know what my current ATO average is, I could see if the amount of water used after water change is above average. Good idea!