PH and water density/flow?
 

I am still trying to figure out why my Coast to Coast Herbie changes in drain flow. Sometimes the level is high, then later, it drops to making a gurgling sound.

I was thinking it was temp? Hotter water in evening, less dense and would not flow as much in the drain. But, temp has been pretty much constant last 2 days and level stayed just at the drain level, making sucking noise. Other thing that I notice changes between day/night, my PH swings .about .3 between night and day.

Could the PH affect how water flows in a pipe?

The only thing i can answer is regarding you P.H drop,this happens when you lights go off,solution is lighting your sump when your main tank lights are off.

If your salinity changes from daily evaporation your density will change which can effect flow. In addition if your sump level changes from evaporation the pump head pressure will change which will also alter flow. Herbie overflows are fairly sensitive and usually require an ATO to keep things stable.

Another solution would be to change the back up drain to a standard standpipe and adjust the flow so some water enters the back-up (standpipe) drain. This way if your flow increases or decreases slightly you will avoid annoying gurgling sounds. The overall noise will be slightly louder than a traditional Herbie but may be acceptable depending on your requirements.

PH will not directly effect flow.

I have an ATO, Salinity and sump level do not change, other than with the level in the herbie

I believe Untamed had this same problem maybe PM him on his solution

pictures of your sump and general plumbing setup would be helpful.

No pics, but pretty basic sump setup. 1" Herbie flows into sump, through some baffles, and Little Giant 4 pumps back to tank. Only other thing running off the LG is a Phos reactor, at a reallly low flow. I just got a Kill-A Watt. Checking the voltage at the pump from lights on/lights out. Should not have a drop, but you never know.

Do you have a ball valve or a gate valve on your herbie? I understand some ball valves are 'inaccurate' or hard to adjust, and I've heard of valves 'adjusting' themselves under pressure... could be the valve.

Ya forgot to add, got a gate valve. Next step is a flowmeter on the sump return line, see what the pump is acctually pumping up to tank.

It's not a major problem, just gets annoying as every 1-2 days I need to adjust the gate.

OK, I have figured it out. My Mains power fluctuated between 117.3-120.6v throughout the day. I'm on a community grid system, so the more power demand during the day, the lover the voltage. Just enough to cause a little flow variation in my return pump. Now, anyone know of a good power conditioner? I am going to try my UPS, see if its constant, but I think it fluctuates with Mains as well, only switches to battery on power fail....

Need to figure out how to make a auto Buck/Boost transformer :D


Edit, Nope, My UPS drops from 118 to 108 upon power fail. so it does not actively condition the power :(

http://www.apc.com/products/family/i...atures#anchor1

They also make a 1000VA unit that is black and has Home Theater written on it so it costs five times as much.

Way to go Sherlock, excellent deduction, I will have to remember that little tip.