About Passive delivery of liquid chlorine when away

[critterdoc]

I've noted numerous references to using pucks when away from the pool for extended times which leads me to wonder if anyone has considered/suggested using a typical primary intravenous infusion set [sans needle] to passively infuse their pool with liquid chlorine. Containers for the liquid could vary but typical refillable plastic one liter [IV fluid] bags can contain 20,000 or more average "drops" of liquid and an IV set can typically deliver deliver a wide range of drops and drop sizes per minute.

I've not yet gotten a handle on the volume of liquid chlorine that forum members are using to maintain balanced pools over time, but cannot help but wonder if a simple IV infusion set would provide a shoot-and-scoot alternative for folks who are getting out of Dodge for a number of days. Inexpensive sets that will deliver 10, 15, 30 and 60 drops per ml/cc. costing less than $2 each are available to health care providers and possibly on the web to non-medical consumers.

It occurred to me that this might provide an extremely inexpensive and consistent method of delivering metered volumes of liquid chlorine over a period of many days depending the individual pools demand.

 

[mas985]

This link is what I use for acid injection but it could also be use for chlorine injection. I am using the pump to control the flow rate but you could also set it up to work only when the pump is off and through the return. You need to add a check valve to prevent back flow.

 

[chem geek]

If you use a pool cover that is opaque to UV, then you will significantly reduce the amount of chlorine demand per day. Even so, it could still be from 0.5 to 1.0 ppm FC per day (unless the water is cool). In a 15,000 gallon pool, this is about 2-4 cups of 6% bleach per day or 1-2 cups of 12.5% chlorinating liquid per day. So unless the pool is very small, use of a one liter IV bag (even if it could hold chlorine, which is not certain) would only be good for 1-2 days if using bleach or 2-4 days if using chlorinating liquid. Mark's solution is better in that larger containers can be used, though it does require a somewhat more complex installation.

Some people have tried poking a large hole in a gallon jug of chlorinating liquid or bleach and having that stand upright at the bottom of the pool (sometimes in a milk carton crate to prevent tipping). The main problem is that the flow rate is not regulated.

Perhaps if you were to enhance your idea by using multiple bags to increase the total volume capacity and then use a lower flow rate from each to extend the time until depletion, then it might be a decent approach. Don't forget that you have to cover the bags with something opaque to UV or else the chlorine will get broken down quickly in sunlight (the delivery tubes themselves could be covered or painted, though that's not as critical if the chlorine doesn't stay in the delivery tube for more than a minute or so).

It would be best to add the chlorine only when the pump is running (something that Mark's system does automatically) so with your drip system you'd be better off running the pump 24/7 in a low speed mode to ensure good circulation.

Richard

 

[spishex]

This link is what I use for acid injection but it could also be use for chlorine injection. I am using the pump to control the flow rate but you could also set it up to work only when the pump is off and through the return. You need to add a check valve to prevent back flow.

That's a cool way to make use of the drain in the strainer housing, but I can imagine some drawbacks to feeding either chlorine or acid in at the front end of your equipment vs. after the filter/chlorinator/heater. How long have you been running that setup?

Anyone ever tried pulling liquid with an ozonator venturi? That could be placed at the end of the line, would only pull when the pump was on and could feed from any size container.

 

[mas985]

I have been running this since the beginning of the year. I too was concerned about putting acid into the input of the pump until I did the actual dilution caculations as well as measure the pump basket PH. What I found was the acid concentration entering the pump was actually lower than if I had added a weeks worth of acid to the pool. I have a 21000g pool and need to add about 1/2 gallon per week. That is a concentration of 1:42000 if added at once to the pool. If I add 1/2 g at a rate of 2e-4 g/min (6 hour run time / 7 days per week) and the pump flow rate is 88 GPM, the concentration becomes 1:440000 or about 10x less concentrated than if I add it all at once.

The key to the whole setup is to make sure draw rates are low enough such that high concentrations in the container are reduced to low concentration after entering the pump basket. The original post showed the injection at the pump basket since that is easy to do and provided a proof of concept but I am currently injecting a bit upstream at the pool side of the suction. This way, acid is only added when the pool plumbing is running and not when the spa plumbing is running. The spa PH would drop too far when the spa was run more than a couple of hours.

I had considered Venturi's before but I couldn't find one that would work in my setup. Venturi's will only work if the pressure differentials between the 3 ports are within a specific range. The ones I had looked at did not allow for a very small PSI range between the input port and the output port. You can use a bypass valve to reduce the output port pressure but that increases the head loss for the system, reduces flow rates and reduces pump efficiency so I wanted to avoid that. Most seem to require at least 3 PSI between input port and output port which is like adding 7' of head to the plumbing. Not very attractive. I still might go that route if I can find the proper Venturi and it isn't too expensive.

 

[spishex]

I have been running this since the beginning of the year. I too was concerned about putting acid into the input of the pump until I did the actual dilution caculations as well as measure the pump basket PH. What I found was the acid concentration entering the pump was actually lower than if I had added a weeks worth of acid to the pool. I have a 21000g pool and need to add about 1/2 gallon per week. That is a concentration of 1:42000 if added at once to the pool. If I add 1/2 g at a rate of 2e-4 g/min (6 hour run time / 7 days per week) and the pump flow rate is 88 GPM, the concentration becomes 1:440000 or about 10x less concentrated than if I add it all at once.

Well that settles that. Excellent homework!

I've seen some ozonators that use small booster pumps to overcome the need for the ball valve, but at that point you may as well be using a metering pump to put the acid in.

Thanks for the details!

 

[investindy]

Removed

 

[257WbyMag]

Critterdoc,

No doubt that you are medical. So am I and I have thought about trying that very same thing. I actually thought about using a vented 60 gtt set (like a nitroglycerin tubing set) and simply spiking a bottle of bleach with it. This of course would be a very temporary thing for maybe a few days at best. Since I know how much bleach my pool requires, I could calculate the drop count to deliver so many milliliters of bleach per 24 hours. It would need to be a vented set since the bleach container isn't collapsible. For my pool, a liter bag wouldn't hold enough bleach. You could have several liter bags in a series though but then things could get really complicated. I would probably set it up to where the end of the tubing just hung over the water. One problem I see is that the bleach in the tubing might lose some strength due to sunlight exposure since the bleach would be going so slowly through the tubing. Anyway, it seems like it would work but it would be temporary at best.

 

[investindy]

Removed

 

[critterdoc]

...in a 15,000 gallon pool, this is about 2-4 cups of 6% bleach per day or 1-2 cups of 12.5% chlorinating liquid per day <snip> Mark's solution is better in that larger containers can be used, though it does require a somewhat more complex installation <snip> Perhaps if you were to enhance your idea by using multiple bags to increase the total volume capacity and then use a lower flow rate from each to extend the time until depletion, then it might be a decent approach.

Hi Richard,

I threw out the idea of using an IV set as an alternative to pucks because of it's because of it's lack of complexity and it's economy. I really don't see container size as an issue. 1 liter IV bags could potentially be free if one had a relationship with a veterinarian or someone who works in a hospital. Heavy duty bags ranging in capacity from 3 to 20 liters are available, some with built-in IV sets, for costs that range from $18 to $36.

http://tinyurl.com/6jmh49 will link interested parties to 5 and 20 liter bags with ports that will accept a standard IV infusion set. (see attachment below)

http://tinyurl.com/6lbxx7 will link to 3 and 6 liter large volume IV bags which contain a built-in permanently attached IV infusion set. (See attachment below)

Jorgensen Labs has long been a respected source of supplies and equipment to Veterinarians. I note that they provide a <buy now> option on their website and it appears that "company info" is not required for registration so they might direct sell without professional requirement.

If anyone has concern about chlorine degrading a typical 1 liter IV fluid bag I will be happy to hang one along with a primed IV infusion set with 6% bleach and let it sit as long as is requested.

 

[gtm]

Dear critterdoc,

Concerning the questions about where you are (another post), I'm guessing near 36th and Florida, but I'm using my wife's useless calculator.

Concerning this post, I sort of wonder how we would mount it by the pool. And be able to leave it for several days, of course.

But more importantly, I've really enjoyed reading your posts. Even it if wasn't your tree. If we'd gone to elementary school together I might've graduated.

Cheers, Gary

 

[critterdoc]

Dear critterdoc,
Concerning the questions about where you are (another post), I'm guessing near 36th and Florida, but I'm using my wife's useless calculator.

Professor, I'd say your wife's calculator generates incontrovertibly fearsome circular probabilities of error. Nowhere to run, nowhere to hide. Please accept my condolences, then destroy that machine. If my wife gets her hands on that technology then my goose is cooked too.

Concerning this post, I sort of wonder how we would mount it by the pool. And be able to leave it for several days, of course.[quote:6oaro4tb]I never suggested that it would be pretty. Just about any ole poolside IV stand that you could hang that sucker from should do nicely.

But more importantly, I've really enjoyed reading your posts. Even it if wasn't your tree. If we'd gone to elementary school together I might've graduated.

Maybe yes, maybe no, but you would have surely been welcomed to join in on the adventure. My elementary educ was directly under the unblinking eye of vintage Pope's Penguins and my mother was the Boss Penguin's secretary. Those early childhood tactical warfare exercises were of great value in surviving my next level of edu - 5th through 12th grade as a boarding student [read: captive] in a zoo that was operated by a frosty band of brothers, the Holy Cross Brothers who showed no quarter and took no prisoners during the mid-fifties to early sixties when there were few rules and little oversight. I've always looked back on the issue of "graduation" with a mirthful gleam in my eye. Maybe I did and maybe I didn't because the robed wonders presented me with an empty tube when I took the walk and I never looked backl Life is good.

Cheers, Gary[/quote:6oaro4tb]