Lesson Learned - Ca Reactor Set Up

[elfloyd]

Some of you may remember the problems I had with my calcium reactor/CO regulator running a muck... lowering pH in my tank... and causing the loss of several fish.

Today I found the real cause of the problem and wanted to report a lesson learned for others.

To feed water into the reactor I tapped into my feed line (sump to display; powered by a mag 9.5). I realized today that occasionally instead of feeding water into the reactor the flow reverses and sucks water directly from the reactor and pumps it into the tank. It also caused negative pressure in the reactor sucking pure CO2 through the regulator. The control solenoid for the reactor did not cut off because the probe was in a drip cup. Thus when the flow was reversed through the reactor, the drip stopped, and the pH probe did not sense a lower pH.

I don't know what triggers the reversed flow, but yesterday I noticed a noise from the reactor. I shut it down, bled air/CO2 from the system and started it back up. It happened again today but while looking things over I knocked the drip line (that was not dripping) into the water and found it was sucking water.

The reactor is shut down now until I pick up a new pump... but just wanted to share.

The link to my original thread is shown below.

 

[ichthyoid]

elFloyd;471324 wrote: Some of you may remember the problems I had with my calcium reactor/CO regulator running a muck... lowering pH in my tank... and causing the loss of several fish.

Today I found the real cause of the problem and wanted to report a lesson learned for others.

To feed water into the reactor I tapped into my feed line (sump to display; powered by a mag 9.5). I realized today that occasionally instead of feeding water into the reactor the flow reverses and sucks water directly from the reactor and pumps it into the tank. It also caused negative pressure in the reactor sucking pure CO2 through the regulator. The control solenoid for the reactor did not cut off because the probe was in a drip cup. Thus when the flow was reversed through the reactor, the drip stopped, and the pH probe did not sense a lower pH.

I don't know what triggers the reversed flow, but yesterday I noticed a noise from the reactor. I shut it down, bled air/CO2 from the system and started it back up. It happened again today but while looking things over I knocked the drip line (that was not dripping) into the water and found it was sucking water.

The reactor is shut down now until I pick up a new pump... but just wanted to share.

The link to my original thread is shown below.

http://www.atlantareefclub.org/forums/showthread.php?t=38306">http://www.atlantareefclub.org/forums/showthread.php?t=38306</a>[/QUOTE]

Is it possible that the juction where you "tapped into your feed line (sump to display)" is [B]acting like a[/B] [B]venturi [/B]and causing a pressure drop which pulls liquid instead of pushing it? If so, it may not be the pump.
[IMG]http://en.wikipedia.org/wiki/Venturi_effect">http://en.wikipedia.org/wiki/Venturi_effect</a>

 

[elfloyd]

That is absolutely what I think happened. The saddle clamp (tap) I used protrudes into the PVC in effect causing a decreased diameter which again enlarges once past the tap.

Quoted from your link:

"A venturi can also be used to mix a liquid with a gas. If a pump forces the liquid through a tube connected to a system consisting of a venturi to increase the liquid speed (the diameter decreases), a short piece of tube with a small hole in it, and last a venturi that decreases speed (so the pipe gets wider again), the gas will be sucked in through the small hole because of changes in pressure. At the end of the system, a mixture of liquid and gas will appear."

 

[ichthyoid]

Cool. Sorry about your loss though. We've all been there, for one reason or another.

 

[oz]

Wouldn't a Check Valve solve the problem?

 

[elfloyd]

I think a check valve will work too.

 

[cjsparky]

Oz;471368 wrote: Wouldn't a Check Valve solve the problem?

It would definitely solve the problem of accidental reversal of flow, but I do not think it would completely solve the problem of CONSISTENT flow...

Make sense?

CJ

 

[ichthyoid]

The check valve will not solve the issue of the venturi effect. As long as there is a pressure drop it will backflow. Also check valves can stick. I suggest a redesign.

 

[elfloyd]

Yep... going to a dedicated pump. To much at risk here.

 

[ichthyoid]

elfloyd;471397 wrote: yep... Going to a dedicated pump. to much at risk here.

+1

 

[weaglereefer]

Or just don't have the return line below the water level. Nothing to back siphon if it's dripping. Why add another pump with more heat to the tank if you don't have to?

 

[elfloyd]

au01st;471465 wrote: Or just don't have the return line below the water level. Nothing to back siphon if it's dripping. Why add another pump with more heat to the tank if you don't have to?

Effluent drip line was not below the water level. Water in the reactor was sucked out, then the negative pressure cause excess CO2 to be pulled through the CO2 reactor. The CO2 was then mixed with water from the sump through the main feed PVC.

No siphoning gong on... just the effect of water pumping from sump to display pulling reactor water (and CO2) with it.