Can you run a pump too slow?

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C

Cajun

0
Dec 16, 2011
124
Prosper, Texas
1st off I'm glad I found this site. It’s been very helpful so far. I am going to move to the BBB method and ordered my TF-100 kit yesterday, I even got the SpeedStir (ill be like a kid on Christmas when my kit arrives). Anyway back to my question...

My pool was finished in November 2011 and we 1st used the spa in late December. I have been keeping the filter pump at 90% when I run it but this weekend I stated playing with the various speeds (full equipment list in the sig file).

here is a breakdown of the Watts used and filter PSI based on the % I have the filter pump set too.
Power - watts - PSI
100% - 2160W - 28
90% - 1600W - 22
70% - 755W - 14
60% - 474W - 10
50% - 276W - 6
45% - 202W - 4.5
40% - 152W - 3
35% and under psi not reading.

my plan for the summer is as follows but I would like your thoughts on this.

filter pump 60% 11am-1pm
filter pump 90% and cleaner 1pm-3pm
filter pump 60% 3pm-5:30pm

Will everything filter properly/efficiently running the pump at 60%? Do I need to make sure the filter pressure is at a certain level to verify things are working properly? Based on this am I moving enough water throughout the day?

I'm sure you guys may need more info but I'm not sure what else to provide so ask away.

Thanks for your help
 
Welcome to TFP!

As susa said, you can run your pump at a much lower speed than that. The EcoStar is most efficient at about 900 rpm. The lower speed limit is mostly a question of skimmer efficiency and creating enough flow to keep your heater happy (when you are using the heater). At extremely low speed the skimmer(s) stop skimming efficiently. When using the heater, you will need to run somewhat faster than the skimmers require to keep the heater happy. The PS-8 will allow you to setup minimum speeds to normal use and for when the heater is on.

You also need to more enough total water through the filter to keep the water clean. Typically the best way to do this is somewhere between 12 and 24 hours a day at a very low speed.
 
so are you guys suggesting going even slower but increasing the run time right. Aside from the heater (I understand the thought behind running flow higher with the heater)

Also I noticed the following at 60%.
I did have suction at both skimmers.
I could feel return water from about 6 inches out.
Filter pressure was at 10% (and its due for a cleaning based on normal run pressure)
now the chlorinator was interesting. I have 3 tablets in it and noticed the water level was barley above the top tablet. I usually unscrew the cap a bit and it quickly fill back up then i tighten but when I did this the water level actually dropped. (I can only assume because of slower flow rate) is this a concern?

I raised the pump to 70% noticed the following
unscrewing the chlorinator cap filled the reservoir. (Also I have the dial set to 4 on the chlorinator so almost all the way open.)
filter pressure was around 12psi
I could feel flow from returns at about 9 inches out.
 
Based on the skimmer action, seems like you could dial back some more.

I think the only concern I have out of reading this is that you are using a tablet feeder ... please keep an eye on your CYA levels before they get out of hand and the chlorine that is added via the tablets is not enough to actually keep your water clear and require a pool drain/fill.

Although I see you are switching to the BBB method ... so hopefully that will result in not using the chlorinator at all and hopefully your CYA is not already too high.
 
The chlorinator not being full isn't a problem. As long as it's providing enough FC for your CYA level it's ok. Having said that, you should stop using the chlorinator except on special occasions like vacations, etc.. Once you have the test kit and post a set of results we can offer more advice.

As said before you can run your pump really slow and keep it running 24/7 and it'll still be fine. Be biggest determining factor in how fast you need to run it is proper circulation. If running it too slow allows part of the water to be stagnant (i.e. a corner) then you'll need to run it a little faster.
 
Thanks for all the advise. I added to my 1st post to show slower speeds as well as the filter pressure at the various percentages. If I go really low I get no PSI at all.

I am leaning toward running the following.

45% 8:30am to 12:30pm
90% plus cleaner 12:30pm-1-45pm
45% 1:45pm-8:30pm.

This is way less power than running it at 90% for 4-5 hours a day (as the pool places suggest). I guess I need to somehow determine how much water I am actually circulating.

Also is there some test that can be done to determine if at low speeds some water in the pool may be sitting still?

Thanks.
 
90% is still pretty high and my first guess is around 77 GPM. Are you sure you really need that much flow rate? Even cleaners usually don't need that much.

If you want some flow rate estimates, I need some additional information:

Pad height relative to the water level.
Suction side plumbing description including: Pipe sizes, number of runs from the pool to pad and length of runs.

The rest I got from your posts.
 
Mark I suspect 90% is more than I need. I do know the spa waterfall and bubblers looks best at 90% or higher (and I have to starve the pool returns for the spa waterfall to look good even at 90%). But for regular filtering and cleaning you are probably right its way more than whats needed. Here are some pictures that might help as well as some answers to your questions.

The equipment is about level with the pool deck and is about 65 ft away from the pool on the side of the house. The raised spa is actually higher than the pumps. (found that out while cleaning the pump basket one day)
Here are some pictures. Thanks again to all for the help.

pump intake side
20120403_155705.jpg


pool return side
20120403_155740.jpg


the pool with 18" raised spa. Pool is roughly 31'x17'
20120402_191630.jpg


full image pad and other pictures are in the pool album
http://s638.photobucket.com/albums/uu106/cajun321/pool/
 
Welcome to tfp, Cajun :wave:

That is a great looking pool you have there :goodjob: I love the multiple fountains.

Just for my curiosity since I am sure Mark and others can understand without, but could you take a picture that shows the whole pad? I am a wee bit confused (normal for me) by some of the "extra" pipes like the one on the second to last picture that crosses over the whole pad.
 

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linen said:
I am a wee bit confused (normal for me) by some of the "extra" pipes like the one on the second to last picture that crosses over the whole pad.
Click to expand...

In the photo bucket album it looks like the low long pipe goes up to an air blower.
 
linen said:
Welcome to tfp, Cajun :wave:

That is a great looking pool you have there :goodjob: I love the multiple fountains.
Click to expand...

Thanks we are very happy with the way it turned out.

Jason was right its a blower, I added another picture in the album. Unfortunatly I can't get a straight shot of the entire pad because there is only about 2.5 ft from the pad to the fence.
 
So for the past week (aside from using the heater over the weekend) I have been running my pump as follows.

7:30am - 1pm - 45%
1pm - 2:15 - 75% - cleaner also running
2:15 - 10pm 45%

The water is extremely clear and sparkles. I am guessing it's because the water is circulating for so long rather than sitting? Based on my current rate 8.3 cents per kWh I am using under $10 a month in electricity to run the pool (assuming my calculations are correct).

For you guys running your pools 24/7 are you noticing you don't really need the pool cleaner As much. It seems the skimmer catches most everything before it has time to sit and sink?
 
Other than sand those meddling kids drag in :blah: I doubt I would need to vacuum/clean much at all other than in late fall. I run 24/7 on low and get great circular water movement...that is when my pool isn't winterized (which it still is :cry: ).
 
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