need help using an SV-1 for Kalk or RO topoff

[pompeyjohn]

I am not sure how to do this, so throwing it out to the community. This one hurts my head. Thanks in advance.

So I am currently adding kalk via auto top off. I am using an Avast kalk stirrer. It works well. However, I'd like to make the PH as stable as possible.

The idea I had was to split the incoming RO water line. Then each branch of that would have a solenoid switches. One line would go to the kalk stirrer, the other would go straight to the sump. Then with a bit of apex programming I'll have the switches open/close depending on the PH probe reading. In theory that works.

I just opened up the two SV-1 packets and was going to plug them into the Apex 832 which has two ports. Which I should have checked first. Because one of the ports is currently being used by the avast ato.

So now I am trying to work out how to do this using only one SV-1 solenoid.

Any ideas?

 

[Dburr1014]

So maybe a tee is needed?

Ro to a tee, one side of tee solenoid the other to the Kalk. When you need Kalk, solenoid is closed. When you don't, solenoid is open. I would think because of slight more pressure, when the tee is open it's the path of least resistance.

Keep me posted if it works.

 

[RSnodgrass]

I split the ro line and simply run 2 dosing pumps, no need for expensive or complex.

You can also run zip ties up the stir shaft easily with Avast and allows you to add several inches of kalk at a time.

If you use pharma grade you will only need to clean once every 1-3mo.

This is prior to refilling. I fill to just below the top zip tie.

 

[RSnodgrass]

This also eliminates the need to test the chamber pH.

 

[RSnodgrass]

As for using one solenoid just add a back flow preventer to one line and the solenoid to the other.

The preventer will add enough back pressure that it will not allow water through when the solenoid is open.

 

[RSnodgrass]

Put the solenoid on the line based on the type. If it's normally closed you must put on the Kalk side so that it pumps ro water in a normal ATO failure scenario vs only putting in kalk.

 

[Yodeling]

Imho, you're overthinking it? Just keep your ATO and Kalk separate (both drawing from same RO reservoir). An hour or so after lights off, turn on Kalk, then run it all night (slow flow via peristaltic pump), then turn it back off before lights on. Tune the flow as necessary to achieve stable PH through the night. (This is assuming you're using CaRx/dosing for Ca/Alk and Kalk is only for PH stability).