Peristaltic Pump Question

[sbe]

I've spent the last couple of days researching the various pumps and systems and what I don't understand is why they all seem to have such high flow rates, even the ones specifically for residential applications.

Am I right that to add 1 ppm of FC to a 30,000 gallon pool one needs less than half a gallon of 12% Sodium hypochlorite? If that is true then even assuming one was running without any CYA why would one need, or want, a pump that is capable of 8-15 gpd (which seems to be the smallest size Stenner makes)?

I must be missing something.

 

[PoolGuyNJ]

Most that use one either use a controller with sensors or a timer.

Scott

 

[Bama Rambler]

As Scott said most people run them on timers or through an automation system. Stenner makes a 3gpd pump, even that's too big if you were to run it 24 hours a day. Most people don't run their filter pump 24 hours a day so the higher volume peristaltic pump is required to inject enough chlorine/acid during the filter run time.

 

[sbe]

So does my calculation sound about right then? I could see running through a gallon of 12.5% on a hot,sunny day (no CYA) especially with a heavy bather load, but does that sound like about the max for one 24 hour period?

 

[Bama Rambler]

Without some actual history it's hard to say but I'd guess you wouldn't use over that amount.

According to pool calc it takes ~32oz (1 qt) of 12.5% bleach to raise the FC 1ppm in a 30k gal pool. So if you lost 4ppm per day, which is certainly possible, it'd take 1 gal/day to maintain the FC level.

 

[sbe]

I was running the same calculation so good to know I didn't slip a decimal point or something.

The pump is an Intelliflo and currently its running 24/7 at the minimum rate (15gpm) which results in about 1 turn/day. I've got an electric pool cover which is closed except when we are actually swimming because we don't have a fence so the FC consumption even without CYA is currently extremely low but.

Looks like I'll have to start searching for a pump on ebay and play around. A dosing pump seems the way to go. Thanks for the help.

 

[Richard320]

Ages ago I worked at a Boy Scout camp with a pool. We had one of those pumps. The outlet was wired into the pump timer. If the filter was on, so was the pump. If it got too high, unplug it for a few hours. That seldom happened; 200 dusty boys/day and a lot of splashout pretty much ensured the FC never got too high.

 

[sbe]

Can't do that with the Intelliflo because it has all the timers internal.

However I found a little box with a ring on the side that I can use to solve the problem. You run the power line for the pump through the ring and the box gives you a signal for when the power is flowing. Use that to control a relay that powers the doser pump. Not very elegant, but it appears to be the easiest way unless Pentair tells me there is an output that tells me the pump status.

 

[PoolGuyNJ]

If the peristaltic pump has a regular 3 prong plug, a cheap AGP pump timer will give you your timed control.

Scott

 

[lovingHDTV]

Can't do that with the Intelliflo because it has all the timers internal.

However I found a little box with a ring on the side that I can use to solve the problem. You run the power line for the pump through the ring and the box gives you a signal for when the power is flowing. Use that to control a relay that powers the doser pump. Not very elegant, but it appears to be the easiest way unless Pentair tells me there is an output that tells me the pump status.

Make sure you don't put both conductors through the ring, you will be disappointed in the results. You can only put one leg through to measure current flow.

I use a couple of these to turn on my in house HEPA filters when the air handler fan turns on.

dave