I've read that the LQ can be finicky with variable speed pumps. Besides removing check valves, are there any other hints to make the two work properly together?
Liquidator and variable speed pumps
- Thread starter deanrinehart
- Start date
There are two primary problems with the LQ and a variable speed pump. First, when the pump is running on low speed there is very little pressure difference, which the LQ depends on. Second, If you are varying the pump speed over the course of a normal day the LQ flow rate will vary dramatically at different pump speeds, which can sometimes make the LQ difficult to calibrate.
There are various changes you can make to the LQ to help with the low pressure difference issue. LQ 3/8 line conversion (How to increase flow) talks about one of the more complex and more successful modifications.
There are various changes you can make to the LQ to help with the low pressure difference issue. LQ 3/8 line conversion (How to increase flow) talks about one of the more complex and more successful modifications.
Jason...
That's pretty much what I had expected. I'll be doing the hose conversion to take care of flow issues.
As for speed/pressure variations during the day, my plan is to run at priming speed for an hour, then low speed for the rest of the day. That first hour will be higher FC flow, so I'll do that before swimming hours, then the remainder of the day will be 'under-flowed' to compensate. Since this schedule would be followed daily, FC variation would be minimal.
Question though. The main reason for buying a variable speed pump is to run low for normal filtration, then push hard for spa use. Could I selectively plumb the LQ to pool suction/pressure only so when I'm running the spa, we don't get bleached? This would require the suction line to be plumbed pre actuated inlet valve...and the pressure line to be plumbed post actuated return. This isn't the recommended location, think it would be an issue?
As an alternative, if I close off the lines from the LQ with a solenoid, I assume I could trigger the LQ to chlorinate in a particular time window while the pump is running at a higher speed and do a heavy timed dose, then close it off for the remainder of the day.
That's pretty much what I had expected. I'll be doing the hose conversion to take care of flow issues.
As for speed/pressure variations during the day, my plan is to run at priming speed for an hour, then low speed for the rest of the day. That first hour will be higher FC flow, so I'll do that before swimming hours, then the remainder of the day will be 'under-flowed' to compensate. Since this schedule would be followed daily, FC variation would be minimal.
Question though. The main reason for buying a variable speed pump is to run low for normal filtration, then push hard for spa use. Could I selectively plumb the LQ to pool suction/pressure only so when I'm running the spa, we don't get bleached? This would require the suction line to be plumbed pre actuated inlet valve...and the pressure line to be plumbed post actuated return. This isn't the recommended location, think it would be an issue?
As an alternative, if I close off the lines from the LQ with a solenoid, I assume I could trigger the LQ to chlorinate in a particular time window while the pump is running at a higher speed and do a heavy timed dose, then close it off for the remainder of the day.
Plumbing the LQ on the pool suction and return lines is a good idea. That should work just fine.
For the different speeds at different times thing, as long as you use the same pattern of speeds for the same period of time each day you will be fine. Taking the spa out of consideration will make this much simpler.
If you are going to run on a fairly high speed for an hour each day, it would be best if that was in the early evening. It doesn't make a huge difference, but it is more efficient to have higher FC levels overnight, when less chlorine is getting lost to sunlight.
The solenoid idea is interesting, but I think you will find it difficult to get a solenoid controlled valve which can hold up to the concentrations of chlorine that occur in the LQ lines.
For the different speeds at different times thing, as long as you use the same pattern of speeds for the same period of time each day you will be fine. Taking the spa out of consideration will make this much simpler.
If you are going to run on a fairly high speed for an hour each day, it would be best if that was in the early evening. It doesn't make a huge difference, but it is more efficient to have higher FC levels overnight, when less chlorine is getting lost to sunlight.
The solenoid idea is interesting, but I think you will find it difficult to get a solenoid controlled valve which can hold up to the concentrations of chlorine that occur in the LQ lines.
I found a solenoid for corrosives...but at $750.00, maybe I'll stay simple...
...but the engineer in me is wondering about alternatives. I remember seeing a simple servo used to pinch silicone tubing to turn on/off a homemade liquid fish food feeder...
...but the engineer in me is wondering about alternatives. I remember seeing a simple servo used to pinch silicone tubing to turn on/off a homemade liquid fish food feeder...
One more question on this...
I don't have any plain pipe between where my skimmers/drain are tee'd and the actuated valve.
Skimmer/Drain tee -> EL -> Actuated valve -> pipe
Could I tap into the el for the suction line or should I just pick the drain or skimmer pipe to tap?
I don't have any plain pipe between where my skimmers/drain are tee'd and the actuated valve.
Skimmer/Drain tee -> EL -> Actuated valve -> pipe
Could I tap into the el for the suction line or should I just pick the drain or skimmer pipe to tap?
I know this is an old thread but I'm considering the liquidator and have some of these same concerns. I have a variable speed pump and typically run it at 45% from 7:30am - 10pm. I have it set to kick up to 75% from 1-2:30 when my cleaner and cleaner pump kick in.
Now the spa is elevated and I will sometimes run the pump at 90% to get a nice full even waterfall when we have guest over or we are outside. Also it runs at 90% when heating the pool. Lastly spa mode runs the pump at 100%.
So based on all this should I even consider the liquidator? Also for people using pucks or swg don't they run into these same issues if they have a variable speed pump? Maybe those are not as fast to create chlorine as flow from the liquidator would, not sure?
Lastly any comments from variable speed pump and liquidator owners would be great.
Now the spa is elevated and I will sometimes run the pump at 90% to get a nice full even waterfall when we have guest over or we are outside. Also it runs at 90% when heating the pool. Lastly spa mode runs the pump at 100%.
So based on all this should I even consider the liquidator? Also for people using pucks or swg don't they run into these same issues if they have a variable speed pump? Maybe those are not as fast to create chlorine as flow from the liquidator would, not sure?
Lastly any comments from variable speed pump and liquidator owners would be great.
I don't own a variable speed pump but I can tell you that they work best with a steady suction head.
You could in theory, make it work for you if you ran the pump on the same schedule every day. That way you could adjust the LQ flow so that it'd add enough FC to handle your daily need. Yeah, it'd overshoot some when running on high and it'd undershoot some when running on low but the daily average could be achieved. This is provided you run the system long enough with enough suction head so that it is able to deliver the required amount of FC per day.
A better choice for you would be an injection pump. It adds a set amount of FC regardless of the main pump setting. I suggest running it on a separate timer from the main pump. That way if you decide to run the main pump outside it's normal schedule it won't affect the amount of FC added.
You could in theory, make it work for you if you ran the pump on the same schedule every day. That way you could adjust the LQ flow so that it'd add enough FC to handle your daily need. Yeah, it'd overshoot some when running on high and it'd undershoot some when running on low but the daily average could be achieved. This is provided you run the system long enough with enough suction head so that it is able to deliver the required amount of FC per day.
A better choice for you would be an injection pump. It adds a set amount of FC regardless of the main pump setting. I suggest running it on a separate timer from the main pump. That way if you decide to run the main pump outside it's normal schedule it won't affect the amount of FC added.
I agree with Bama. I tried the Liquidator and a variable speed pump. I tried many different configurations and could never get consistent CL flows. I have a single variable speed pump, no spa but do have a water feature that spills into the pool and a bubbler in the sunshelf. The pump is kicked up to a higher speed when using the water features and for skimming. This would result in over chlorination when the my kids and their friends were in the pool all day. I could never get the right amount of flow for my pool on low-speed where I run at for most of the day and was having to increase my high-speed run time. This defeats one of the purposes of a variable or two-speed pump.
I went with a Stenner pump and it has worked perfectly. I use an extra relay from my Easytouch system to inject 3 times a day. I had planned to use a separate timer, but figured out a way to use my existing system. I have found the chlorine level to be very stable and is completely independent of pump speed or run time.
I went with a Stenner pump and it has worked perfectly. I use an extra relay from my Easytouch system to inject 3 times a day. I had planned to use a separate timer, but figured out a way to use my existing system. I have found the chlorine level to be very stable and is completely independent of pump speed or run time.
Forgot to add. I have a 15gallon tank. I was able to go on a 10 day vacation this summer and did not have to ask anybody to add bleach. I can probably go a little longer, since Walmart and HEB bleach is now 8.25% vs 6%. Last summer I left for 10 days and the Liquidator decided for some reason not flow the same amount of bleach and I came home to a pool that was starting to turn green.
Thanks guys I'll look into the stenner pump options and various post on here as I have several questions about them but don't want to derail this thread. Thanks.
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