Using Filter Pump to Lower Water Level

[Jaywalker]

I'm sure this has been discussed previously but I'm not sure how to structure the words to search for it, so I would appreciate being led by the hand to the right words or links.

In the past I've lowered the water level a lot - 50% - 90% - when the CYA level got too high. Since then, however, I've fought a long and hard battle against mustard algae and I don't want to put a rent sump pump back in the pool, so I instead want to lower the water level more often and by lower amounts 5% or 10%, maybe, multiple times, as needed. I can buy a reasonable sump pump, or this question, should I risk using the filter pump and with a garden hose attachment. It's slow, and it appears I risk losing prime as the skimmer basket apparently handles 90% of the water intake to the pump.

 

[borjis]

That won't work unless you have a main drain....then you would just use that.

The first time I did some partial drain/refill I tried with a vac hose to the bottom of the pool
then the other end in the skimmer suction hole.

When the water got low enough under the skimmer it was drawing air fast.



Are you still fighting mustard algae?
What happened?

Mustard sucks, but it can be eliminated. I had that battle in july. no fun but got rid of it while slamming for 1 and a half weeks.

 

[OldPoolMan]

It's best to buy a cheap sump pump. It will save you a lot of time to throw it in the pool and not have to change anything with your equipment.

 

[Jaywalker]

Well, a garden hose attached to the faucet on the filter pump housing is clearly the easiest, and it does work. (I've used it to lower the water level an inch during heavy rains rather than allow the overflow hole in the pool to drain and flood our yard.) My concern is that the valve under the skimmer basket will lose its seal when the water level is lower than the valve (when lowering the water by more than three inches), causing trouble with air in the pipes. As the water level drops below the skimmer float valve, water would stop entering the pipes from there and the bottom drains (normally only 10% of the water exiting) become 100% of the water exiting.

Re mustard algae, I followed TFP advice. In my case I shocked at mustard level for 10 days (!) until the overnight chlorine drop test read appropriately, plus three more days because mustard is tricky and hardy. I threw away all floats, toys, tools, and replaced them. I maintain the free chlorine at 15% of the CYA level, a little higher than I like it, but anything's better than mustard. I mix a triclor treatment with clorox in order to ensure I won't drop below that 15% level. So, that's why the CYA climbs a little and why I want to make sure it doesn't get too high by more frequent, smaller pool drainings.

So, the verdict is I need a sump pump for draining, rather than replacing my skimmer float with a more effective stopper during draining?

 

[jblizzle]

You need to be able to isolate the floor drain ... and the float diverter under the skimmer basket does not do a very good job sealing.

Sump pump is the easiest path forward.

 

[Jaywalker]

Okay, fair enough - a sump pump it is.

Which pump? So many of them seem to last only short times. The Zoeller M53 or M57 series appear long-lived, but...

1. their power cords are only 9 feet long, which is not enough to make it to the pool surround.

2. Do I need to be concerned about the design differences? For instance, a basement sump pump is designed for frequent on-off, small volumes, while the pool pump will handle larger volumes with one on-off cycle?

 

[jblizzle]

For how rare you will use it ... a cheap one from Harbor Freight would likely be fine. Although they do drain more slowly.

 

[Jaywalker]

For how rare you will use it ... a cheap one from Harbor Freight would likely be fine. Although they do drain more slowly.

Once or twice a summer, I expect, but I'd rather pay more upfront than have to replaced burned-out unit when I need it. I don't worry about how slowly they drain. Even a garden hose one would work - after all, I was willing to work with a garden hose off the filter pump! (It appears I'll add about 15ppm CYA per year and I'll want to keep it around 50ppm.)

 

[jblizzle]

You should only need it once every 3-4 years. There is no reason to be dumping water that often following our chemical recommendations.

 

[n240sxguy]

I've got one of these, and it works good. I ended up using it for a cover pump when my little POS cover pump broke. You can use the garden hose fitting, or make up something in 1-1/4" hose.
Amazon.com: Superior Pump 91025 1/5 HP Thermoplastic Submersible Utility Pump: Home Improvement

 

[Jaywalker]

You should only need it once every 3-4 years. There is no reason to be dumping water that often following our chemical recommendations.

Well, I'm not using the recommended BBB exclusively during the high summer in south Texas - I'm using triclor pucks, also. If I start the season at CYA 50 I'll be close to 60-65 at the end, at which time I'll need to keep FC at 10 or so, higher than I want to keep it. So, if I'm able to maintain my CYA between 50 and 60, however long it takes to get there, I'm willing to do a little draining to keep it there.

 

[MitchRyan912]

That won't work unless you have a main drain....then you would just use that.

The first time I did some partial drain/refill I tried with a vac hose to the bottom of the pool
then the other end in the skimmer suction hole.

When the water got low enough under the skimmer it was drawing air fast.

Do you have a suction line besides the skimmer? I have one (I guess it's called a vacuum line?) on the same wall as my skimmer, and it's isolated from the skimmer plumbing. I just plug the bottom of the skimmer when it gets low and use the vac line to drain the water. I use a 90 elbow and point it down to keep draining below the actual port in the wall.

 

[jrs_diesel]

You need to be able to isolate the floor drain ... and the float diverter under the skimmer basket does not do a very good job sealing.

Sump pump is the easiest path forward.

I drained 14-15k out of my pool last year using the main pump. My pump has a three way on the output to send water to the filter or the pool cleaner line. I rigged a hose to the pool cleaner line running to the sewer cleanout on the back of the house. My main drain is plumbed to the skimmer, so once the pool drained lower than the skimmer the float diverter shut. But like Jason said, and I found out, it does not have a perfect seal. I learned I had to keep water in the skimmer above the float diverter so the pump would not suck air. Worked well during that 5 hour drain.

 

[Jaywalker]

I've got one of these, and it works good. I ended up using it for a cover pump when my little POS cover pump broke. You can use the garden hose fitting, or make up something in 1-1/4" hose.
Amazon.com: Superior Pump 91025 1/5 HP Thermoplastic Submersible Utility Pump: Home Improvement

Okay, maybe I'll try a cheap sump pump. That one looks as if if has fewer reports of premature burnout, maybe because it's rated for continuous duty. Thanks. Do you use the additional check valve?

MitchRyan912: Do you have a suction line besides the skimmer?

Hmm. Not as such, but there are two holes in the skimmer, one to which I attach the vacuum and the other which I assume to be the other end of the pool-bottom drain. The only other place in the pool for an attachment is the outflow for the auto pool cleaner, so basically, I think no.

jrs_diesel: But like Jason said, and I found out, it does not have a perfect seal. I learned I had to keep water in the skimmer above the float diverter so the pump would not suck air. Worked well during that 5 hour drain.

I'd never even considered the possibility of ensuring the seal by keeping water over the diverter - thanks.

 

[n240sxguy]

Okay, maybe I'll try a cheap sump pump. That one looks as if if has fewer reports of premature burnout, maybe because it's rated for continuous duty. Thanks. Do you use the additional check valve?

Hmm. Not as such, but there are two holes in the skimmer, one to which I attach the vacuum and the other which I assume to be the other end of the pool-bottom drain. The only other place in the pool for an attachment is the outflow for the auto pool cleaner, so basically, I think no.

I'd never even considered the possibility of ensuring the seal by keeping water over the diverter - thanks.

I don't have a check valve with mine. Don't really see any need for one if you're just draining water.

If the diverter doesn't seal perfectly, you may be able to take it out and use a section of reinforced vinyl hose to make a U shape to connect the two ports. Just wedge it in each one and the pump would pull from the main drain exclusively.


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[Jaywalker]

Okay, thanks.

 

[jrs_diesel]

I'd never even considered the possibility of ensuring the seal by keeping water over the diverter - thanks.

Doesn't take much. I poured a bucket of water into the skimmer about every 10-15 minutes to maintain the water seal after the diverter valve shut.


Using a U shaped hose would work too, but could run into the same problem as the diverter, maintaining an effective seal to keep air out.

 

[Jaywalker]

I've got one of these, and it works good. I ended up using it for a cover pump when my little POS cover pump broke. You can use the garden hose fitting, or make up something in 1-1/4" hose.
Amazon.com: Superior Pump 91025 1/5 HP Thermoplastic Submersible Utility Pump: Home Improvement

For posterity, I tried one of these pumps but it didn't work out for me. It worked, yes, but so slowly I couldn't rinse my toothbrush with it - I measured one gallon per minute at 7 feet - much less than the 14 gallons per minute at 10 feet in the specs. That wasn't enough so I'm looking again.

 

[n240sxguy]

For posterity, I tried one of these pumps but it didn't work out for me. It worked, yes, but so slowly I couldn't rinse my toothbrush with it - I measured one gallon per minute at 7 feet - much less than the 14 gallons per minute at 10 feet in the specs. That wasn't enough so I'm looking again.

Not sure where they come up with numbers like that. Mine was pumping 5gpm when I was using it as a cover pump. That's zero lift, and the resistance of about 40ft of hose. It was much less than the specs, but still plenty for my needs. Sorry you didn't have better luck.


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[bignick]

I'm using a Wayne VIP50 and it pumps like a mofo. Using a 1.25" x 20' discharge hose and about 4' rise, I estimate it's pumping about 1000 gph. It comes with a garden hose adapter, but I wanted a higher flow. The cord is 8' long, so I just put it in the shallow end and move it later if I have to. I'm on my second unit because evidently, the salt and chlorine blew the seals and it started leaking oil. So now I make sure to flush out with tap water after each use.