New Automatic Chlorinator for Rental Pool

[Rental Pool]

This pool is about 22K gallons for a rental house. I plan to have it re-plastered when the weather cools down. I service it once a week. I don’t want to rely on my tenants to add chemicals, as they tend to be inconsistent, so I want to install an automatic chlorinating system. This city has banned salt based water softeners, and salt water is not allowed to be drained down the sewer or the street. I also have copper pipes in this pool. For these reasons, I have decided against installing a SWG. The other option seems to be a peristaltic pump system, but I’d like feedback to determine what my best options for purchase and installation might be.

This area is very hot (Southern California). I’m thinking it would be best to add all the chlorine at the start of the filter cycle, so it can enter the pool in the dark rather than in the sunlight. I plan to input the chlorine after the filter, just before entering the pool. I’m thinking of using a recycled 50# tab container to store my liquid chlorine. It holds about 6-7 gallons, and I figure that should be more than enough to last a week, before I add more 10% chlorine. I may put this container in a larger one and fill the voids with insulation foam, to reduce chlorine deterioration from heat and sun.

People seem to focus primarily on Stenner pumps, here. Which pump (model #) would you recommend, allowing me to both input up to 1 gallon per hour, yet also allow me to adjust the flow to keep the chemical balance stable? How would you suggest I wire a timer, connecting it to the filter timer, so the chlorine is released starting about 10 minutes after the filter kicks in and stays on for about an hour? I only have 110v available at the pool.

I’d appreciate any installation suggestions, based on what you’ve discovered has worked well in hot, sunny conditions. Thank you.

 

[tim5055]

While adding all of the chlorine at once is similar to the way folks manually chlorinate, I really don't think it makes a difference when dealing with automation.

I like a slow steady addition of chlorine whenever the pump is running. Once you get it dialed in you will basically keep a level amount of chlorine in the pool - depending on how you run the pump. I have mine set for 3 hours in the morning and 3 in the afternoon. So, chlorine is added in the AM with the pump, slowly goes down due to the sun during the day and then brought back up,to the proper level in the evening before it shuts off for the night.

You say you only have 110v "at the pool", but the Stenner is installed at the equipment pad with the pump and filter. Now, this is just my opinion, but I think it is easiest to just wire the Stenner up with the pool pump. When the pump is running the Stenner is adding chlorine. The Stenner has an override switch built in, so you can turn it off if you need to for some reason.

In my mind multiple timers and trying to keep them in sync is just a recipe for a problem when dealing with a pool at a rented house. Additionally, I would suggest increasing the size of your chlorine container. In other posts you say you are 300 miles away and only get to the house once a week. If you size it for that one week you don't have any capacity for issues arising or even you skipping a week to take a vacation. My 15 gallon tank is perfect I think. At the height of the summer I only need to fill it every three weeks and spring and fall when the consumption is a little lower it will last over a month.

You can check this thread out to see my install including photos: My Stenner Install - July 2014

 

[Rental Pool]

Tim, thank you for your response. I'm sensing you control the amount of chlorine by the amount of time the filter runs. Should I run the filter at night, due to chlorine deterioration from UV during the day? I thought I read on this site that chlorine should be added when it is dark. The challenge I see is the pool cleaner and filter would run for a shorter period in the winter, unless I dilute the chlorine.

I still have concerns about storing 15 gallons of chlorine under a hot sun. You say your 15 gallon tank last 3-4 weeks, so a 6-7 gallon tank would last one week with ease. I don't take vacations, but if I did, I'm sure I could ask my tenants to add chlorine for that rare occasion. What are your thoughts of one tank inside another, with the space filled with insulation foam, to protect the chlorine from the sun and heat? Any other suggestions for this?

My comment about 110v at the pool was to say I don't want to rewire for a 220v pump. I realize all is connected by the filter. Is this the pump you recommend? 45MPHP2 - Buy Stenner pumps chemical feeders - $208.00

 

[rphpool]

See my post #27
Liquidator Still the Best Option? - Page 2

I store my 15 gallon tank inside a garbage can with lid on to keep heat off of it. I also installed a shade sail over all my equipment. I run my pump 4 times per day and Stenner comes on at those times also. I try to keep my chlorine at a constant 5.5ppm that way ( no high and lows ).

 

[tim5055]

Tim, thank you for your response. I'm sensing you control the amount of chlorine by the amount of time the filter runs. Should I run the filter at night, due to chlorine deterioration from UV during the day? I thought I read on this site that chlorine should be added when it is dark. The challenge I see is the pool cleaner and filter would run for a shorter period in the winter, unless I dilute the chlorine.

I still have concerns about storing 15 gallons of chlorine under a hot sun. You say your 15 gallon tank last 3-4 weeks, so a 6-7 gallon tank would last one week with ease. I don't take vacations, but if I did, I'm sure I could ask my tenants to add chlorine for that rare occasion. What are your thoughts of one tank inside another, with the space filled with insulation foam, to protect the chlorine from the sun and heat? Any other suggestions for this?

My comment about 110v at the pool was to say I don't want to rewire for a 220v pump. I realize all is connected by the filter. Is this the pump you recommend? 45MPHP2 - Buy Stenner pumps chemical feeders - $208.00

Actually I have a variable Stenner, so I control it in three ways 1. % of chlorine; 2. Amount of time pump runs; 3. % of injection

But, I generally leave the run time the same and only latr this year did I experiment with a different % of chlorine.

Following my methjod if you ha=ve a 110v pump just get an adjustable flow rate 110v Stenner (they are available both ways) and wire them up together.

RPH has already coered the issue of protecting the chlorine.

 

[Rental Pool]

Here is the setup I have: Dropbox - Pool Filter I'm thinking of drilling and tapping either the top horizontal coupling or the vertical pipe before it elbows out and splits off to my two return lines. If I drill into the horizontal coupling, would you recommend I do so on top, bottom or horizontally? Do one of these make more sense to you, or do you have another suggestion? Would it help to use insulation foam (sprayed expanding foam or peanuts), or should I just place the tank in a larger covered container? I can put shade cloth over the top, allowing for air circulation.

What are the advantages/disadvantages of running the entire time at night, splitting the run-time between evening and morning or splitting the run-time into every 6 hours (6am, noon, 6pm & midnight or 8am, 2pm, 8pm and 2am)?

Bama Rambler suggests high pressure fixed rate pumps rather than variable due to increased noise and maintenance. Is there a significant advantage when going with the variable rate pump? Do you agree on the high pressure units?

Thank you for your feedback.

 

[tim5055]

I don't think it will make a difference where you tap, but many feel it is better to tap into a fitting due to the thicker wall over the pipe.

Bama and I agree on using a high pressure pump, but I feel that with the installation next to the pool pump you are never gong to hear the click of the variable rate Stenner. I just like having the ability to dial up or dial down the injection rate.


A tank inside another tank will give you protection from a chlorine spill should the primary tank develop a leak, but I don't see much other benefit. The small tank you are planning means chlorine will only be in it for a week at most, s I don't think degradation will be a huge concern. But, as always I defer to Chem Geek as he can tell you the exact rate the % will decline.

 

[Rental Pool]

With a tank of chlorine sitting under a hot sun on 100°+ days, I'd find it hard to believe the chlorine wouldn't degrade faster. Hopefully, Chem Geek will sound in on this issue.

Since my pool is about the same size as yours, do you find that running your cleaner and filter for 6 hours a day is enough? I've been running it 10 hours a day, but it does look good.

If I go with the variable model, would it make more sense to get the 45MHP10 or 85MHP5 rather than the 45MPH2, making it easier to shock the pool, if needed? On second thought, maybe it would make more sense to shock the pool manually, so my tenants won't have to turn it back down to normal. What are your thoughts on their rain roofs?

 

[chem geek]

So you definitely want to shade the containers if at all possible. If you can't shade them, then they should be painted reflective white so that they don't absorb heat from the sun (but shade is better).

According to the Saugus, CA historical averages, August is the hottest averaging 95ºF days and 55ºF nights. This is a 40ºF temperature spread so has a weighted average (due to non-linearity of bleach breakdown by temperature) of around 86ºF so let's use 90ºF to handle the 100ºF days. As shown in this post, 12.5% chlorinating liquid stored with weighted average temperature of 90ºF gets to 10.9% after one week, 9.9% after 2 weeks, 8.4% after one month. 8.25% gets to 7.8% after one week, 7.4% after 2 weeks, 6.7% after one month.

So if you were going to have the chlorine in the tank for more than a week or two, it may make more sense to get 8.25% bleach if it's around the same price per FC since it will lose less proportional strength, losing 19% over one month compared to 33% for 12.5% chlorinating liquid.

 

[Rental Pool]

I plan to use 10% chlorine and add more chlorine every week. I'm thinking of using a 7.5 gallon container, but putting 6 gallons in it. I figure that should be more than enough for a week, once I re-plaster the pool and start out with good numbers. Once I know my actual usage, I'll limit what I put in the container weekly to that amount. What are your thoughts regarding putting the container in a larger one and filling in with either spray expanding foam or insulating peanuts around the center container? I would then put shade cloth above it. Would that help?

 

[chem geek]

Insulation won't keep it any colder in the long term (but keep reading...). It will eventually get to the average day/night temperature though the good news is that it won't get to the high day temperature so in that sense it could help. So instead of being equivalent to an 86ºF temperature (due to non-linearity of chlorine breakdown vs. temperature), it would be at a roughly 75ºF temperature. So yes, the insulation should help.

 

[Alex_H]

Thank you for this thread. We have a similar decision in the Fort Lauderdale, FL area. There is room on the pad for the 8 Gallon Tank, but it would get some direct sun. If I could figure out how to shield/insulate it, it might make the difference.

 

[rphpool]

To answer question on injection point. I put mine to the side ( on joint for more threads ) facing in a direction that I could not accidentally hit it. Some point it under the joint for same reason, I just did not have room to get drill in that direction. Get the rain roof, it is cheap insurance since water from driving rain or water sprinkler can get inside unit. Are you able to attach a sail shade over your equipment? I bought mine at HD for $35 ish each ( 12x12 or 16x16 can't remember) and attached from house to fence. I do not have any scientific data but it seemed I had to increase my Stenner run time when tank was exposed to full sun and was half way down or more. Since putting in garbage can and sun shade I have been able to turn down Stenner run time through the whole 15 gallon tank use.

 

[lvrpl]

So you definitely want to shade the containers if at all possible. If you can't shade them, then they should be painted reflective white so that they don't absorb heat from the sun (but shade is better).

According to the Saugus, CA historical averages, August is the hottest averaging 95ºF days and 55ºF nights. This is a 40ºF temperature spread so has a weighted average (due to non-linearity of bleach breakdown by temperature) of around 86ºF so let's use 90ºF to handle the 100ºF days. As shown in this post, 12.5% chlorinating liquid stored with weighted average temperature of 90ºF gets to 10.9% after one week, 9.9% after 2 weeks, 8.4% after one month. 8.25% gets to 7.8% after one week, 7.4% after 2 weeks, 6.7% after one month.

So if you were going to have the chlorine in the tank for more than a week or two, it may make more sense to get 8.25% bleach if it's around the same price per FC since it will lose less proportional strength, losing 19% over one month compared to 33% for 12.5% chlorinating liquid.

Your post talks about heat here - so even in the shade, if the ambient temperature is 90 degrees (which it easily is here in DFW), you'll get this kind of bleach degradation? Just trying to get a feel for how much bleach to hold in the tank at any given time. For some reason, I had thought that sunlight gave those types of degradation rates, and that heat only did a little.

 

[Rental Pool]

rphpool, as you can see in my photos on post #6 above, I could drill into the return line either horizontally (going under the intake) or directly downward. Which would you recommend? I'm thinking downward would offer the most protection. I may just build a wooden shelter, covering the concrete from the motor to the diverter valve, rather than use the shade sail, as it would hold up for a longer period and would provide more protection from the elements.

 

[chem geek]

Yes, even out of sunlight the bleach will degrade because of the temperature. The degradation in the chart is from temperature alone. Not from sunlight exposure. You should have direct sunlight on the chlorine under any circumstances so if the tank is not shaded it should definitely be opaque.

 

[rphpool]

rphpool, as you can see in my photos on post #6 above, I could drill into the return line either horizontally (going under the intake) or directly downward. Which would you recommend? I'm thinking downward would offer the most protection. I may just build a wooden shelter, covering the concrete from the motor to the diverter valve, rather than use the shade sail, as it would hold up for a longer period and would provide more protection from the elements.

Since it is rental I would go under the pipe if you have room. The renters are not going to be as careful around the equipment as you would. I can see them breaking it off and not calling you until pool is nice and green !

 

[Rental Pool]

I will tap it into the bottom of that horizontal coupling. Maybe I'll also add insulation around it for better protection. What is the best way to lower the water level below that pipe, so it doesn't leak when I am drilling and tapping? What size drill and tap are needed for the 45MHP2?

 

[rphpool]

A 1/4" or 1/2" Female NPT (FNPT) connection is required for installing the injection
fitting.
I think this is it not at home at the moment.
Shop IRWIN Tap and Die Set at Lowes.com

 

[Rental Pool]

I've got a 1/4-18NPT (National Pipe Thread) tap, which is American standard pipe thread, but the link you gave me is for a 1/4-20NC (National Course) tap which is used for nuts and bolts rather than pipes. The installation manual calls for pipe thread. Please let me know if I am mistaken. Here is a link for the 1/4-18NPT tap Irwin HANSON Pipe Tap, Taper Point, NPT, 1/4 - 18 TPI, 4-Flute - Walmart.com