Pump speed and spa spillover

monsterlab

Member
Mar 13, 2017
22
Riverview, FL
Hi everyone. I'm the proud owner of a new pool, and I have a (hopefully) quick question about pump speed. I have a 9,000 gallon pool with a raised spa that spills over into the pool. The pump is a Hayward EcoStar SP3400VSP. The builder set the time to run from 8AM to 8PM at 3250 RPM. From what I've been reading on this site, that seems a bit high for my pool. I tried lowering it to 1,000 RPM as a starting point, and that seems to work fairly well, but the water spilling over from the spa into the main pool is a tiny trickle. I have to ramp the RPMs up to about 2500 to get a decent amount of spillover from the spa into the pool.

I was wondering if I should find the middle ground between low RPMs and decent spillover and run with that, or set the timers to run at a low speed for most of the day, and then kick on a higher speed for an hour or two to get the spa water circulating.

Thanks in advance for the advice!
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,423
Pleasanton, CA
monsterlab said:
Visually, no. I'm more concerned about circulation. It doesn't seem like enough water is leaving the spa to recirculate through the filtration system.
In spillover mode, the water has no other place to go but into the pool so you are getting circulation and it really doesn't take much time to achieve that. However, if you are only operating in spa mode, it will take more time. If possible, operate in spa mode for only part of the run time and then switch to pool mode. Most controllers will support this.
 

mwalling

Bronze Supporter
Sep 17, 2016
188
Dallas, Texas
From what I've been reading on this site, that seems a bit high for my pool. I tried lowering it to 1,000 RPM as a starting point, and that seems to work fairly well, but the water spilling over from the spa into the main pool is a tiny trickle. I have to ramp the RPMs up to about 2500 to get a decent amount of spillover from the spa into the pool.


Thanks in advance for the advice!
As I've come to understand, no two pools are the same but in my case, I have a 3-way valve that allows me to adjust the amount of return between the pool and spa returns. To keep the flow aggressive over the spillway, I divert about 1/3 to the spa when running on low speeds. I also always use around 2250 as my low setting and never run it on 1000 for this very reason. At 2250, my energy consumption is negligible.

Hope this info from a novice helps!


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monsterlab

Member
Mar 13, 2017
22
Riverview, FL
I divert about 1/3 to the spa when running on low speeds. I also always use around 2250 as my low setting and never run it on 1000 for this very reason. At 2250, my energy consumption is negligible.
I like this idea. I'm going to set the pump to 2000 and divert some of the pool return to the spa and see if that increases the spillover.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,423
Pleasanton, CA
You should be able to run at a much lower RPM to save energy costs. Remember that the more aggressive the spillover, the faster PH will rise.
 

monsterlab

Member
Mar 13, 2017
22
Riverview, FL
You should be able to run at a much lower RPM to save energy costs. Remember that the more aggressive the spillover, the faster PH will rise.
I'm not opposed to running at a lower speed. I'm all for saving money on my electric bill. I guess my concern is that water isn't leaving the spa fast enough to run through the filtration system and be replaced. Sorry if I sound like an idiot. This is all new to me.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,423
Pleasanton, CA
I'm not opposed to running at a lower speed. I'm all for saving money on my electric bill. I guess my concern is that water isn't leaving the spa fast enough to run through the filtration system and be replaced. Sorry if I sound like an idiot. This is all new to me.
I am confident that you could run at 1000 RPM and have the return split between the spa and pool and still have proper circulation in less that a couple of hours.

My pool is over twice as big as yours and I can get full circulation and mixing of the water in 30 min on low speed. Again, it doesn't take much. You can confirm this for your pool by testing FC around the perimeter of the pool after a couple of hours of run time. The FC levels should be about the same.

What is your method of chlorination and how long do you currently run the pump?
 

monsterlab

Member
Mar 13, 2017
22
Riverview, FL
I have a Hayward SWG for chlorination. I'm currently running the pump at 3250 RPM for 12 hours per day. This is what the builder programmed, and I know that's way too high.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,423
Pleasanton, CA
What is the current SWG setting (%) and have your confirmed the FC level is appropriate for your CYA level? Normally you want a FC level at least 5% of the CYA level for an SWG.
 

monsterlab

Member
Mar 13, 2017
22
Riverview, FL
The SWG is currently at 50%. I checked the FC yesterday, and it was right at 3. CYA was at about 50. The SWG was activated on Saturday and I took this reading yesterday.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,423
Pleasanton, CA
Which cell do you have? T-CELL-15 9 or 3? 50% seems a bit high for a 9k pool but you may have a small cell.

With your current cell, you could cut run time in half but you would need to run at 100% for the SWG.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,423
Pleasanton, CA
50% seems very high for that cell, size of pool and length of run time. That is close to 5 ppm of FC per day which means your extinction rate is over 60%. You might want to raise your CYA level to 80 ppm so you can lower the SWG %. Otherwise, you may have something growing in the pool. How does the water look?
 

monsterlab

Member
Mar 13, 2017
22
Riverview, FL
The water looks fine, but it has only been running under the SWG for just over 48 hours so probably too early to tell what the long-term effect will be. The pool has had water in it for about a month now, but we were using chlorine tablets during the break-in period.

What are your thoughts on lowering the pump speed to 2000 running at 12 hours per day and keeping the SWG at 50%? Still too high?
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,423
Pleasanton, CA
You may want to wait a couple more days until the SWG settles out. It may continue to climb for a few days.

But eventually, I have no doubt that you will be able to reduce both run time and RPM.
 

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