Homemade Chlorine Injection System

[tcat]

Split off of this topic.

Think I'm going to try this method. Curious if acid and Clorox can be mixed (in same blue jug). I assume not, but how about 2 jugs feeding into a "T" into the basket? A check valve on each line. Going to do the Clorox first, but curious about a dual method.

I assume the blue jug has a hole open to atmosphere so it doesn't collapse, right?

 

[JasonLion]

Re: Homemade Acid OR Chlorine Injection System

NO, do not mix chlorine and acid, either in the same jug or in feed lines. The concentrated solutions react to form chlorine gas, which is highly poisonous. Once mixed into the pool water everything is fine.

 

[tcat]

Re: Homemade Acid OR Chlorine Injection System

Kind of assumed th. I'm mainly needing the chlorine set up (4-8 oz. per hour of 8.25%). Anyone tried this type of valve?

http://www.usplastic.com/catalog/item.aspx?itemid=29060

Going to use 2 pieces of wood and a small clamp until I decide on a valve, but those look pretty "tweakable". Or is the 1/4" tubing you use too rigid?

PS: What prevents pump from losing prime if tank has small vent hole? I know if I have a microscopic leak on the basket lid the pump will lose prime.

edit: Started my install. Went to HD bought $21 of stuff (1/4" threaded to 1/4" adapter for connection to pump plug hole, 50' 1/4" vinyl tube, 1/4 to 1/4 ball valve, HD orange bucket and Lid). Filled the HD bucket with water 1 quart at a time and marked each line. First tested the ball valve to make sure no leaks. Barely opened the ball valve with one end of tube in bucket half full of water watching end to see when suction just started. Currently waiting an hour to see how many lines the level goes down. This is a test with no drip restrictors. Feedback later.

edit 2: Definitely needs a needle valve or drip buttons. Went from about 2oz. per hour to 2quarts per hour, just tweaking ball valve about 3 degrees. Also, after pump is off, level in pail keeps going down. How to stop that? Is pail supposed to be air right? Going to experiment pinching tubing tomorrow.

 

[DreamKiller]

Re: Homemade Acid OR Chlorine Injection System

Just my 2 cents. I tried all last season to get a working setup. Even tried the pinch value you asked about. Never could get it to work well. Either too much flow or it clogged up in just a few days. Very tricky to get it to work reliably. So I ended up ripping it all out for the winter. Not sure I will try again this year. I am just about convinced an expensive injection pump is the only real sure way to go. Good luck! Let us know how well you get it to work.

Sent from my SAMSUNG-SGH-I577 using Tapatalk 2

 

[tcat]

OK, the "pinch valve" doesn't really work well. As the day gets warmer the tubing gets softer and stops flow after it is tweaked in. I was able to get perfect flow with the cheap ball valve from Home Depot, but very difficult to tweak in. Pretty sure I can make the SMC needle valve from US Plastics to work. Looks like I'll need a check valve too, water drains out of the bucket "almost" as fast with pump off as with pump on (my equipment is at least 12" above pool level). It's very easy to get a flow reading using the 40ml tube from TF Test kit. Just fill with water with 1/4" tube in it and watch level. My goal is 5ml per minute (= 10 oz per hour), very easy to watch it for a minute. At most I add 32-40 oz per day, so a 5 gallon HD bucket is good for 2-3 weeks (if all goes well). Hello liquidator if not... just prefer DIY (even if the Liquidator was only $50).

So a 3/16" check valve goes into a 1/4" OD tube? $22 more with shipping... so about $45 total, hopefully that will do it.

64047 2 Each $0.76 $0.76 $1.52 3/16" PP Standard Check Valves
22149 1 Each $10.87 $10.87 $10.87 1/4" FNPT x 1/4" FNPT PP Needle Valve
60418 3 Each $1.15 $1.15 $3.45 1/4" Nom. Tube OD x 1/4" Male NPTF Black PP Male Connector

 

[tcat]

Help! I have all my "parts", but can't get water (which will be Clorox) to stop draining from my Home Depot bucket when the pump is off.

I have a connector to the drain port on the pump basket, to tubing, to check valve, to on/off ball valve, to bucket of water. When I open the ball valve water flows from the bucket fairly quickly (into the basket/pool).

My pump is about 12" above water level, bucket is on pad next to pump. Does the bucket need to be below pool level?
If I have an air leak I lose prime, so this is essentially an air leak. Do I seal the bucket lid? If so won't the bucket collapse on vacuum?

 

[mas985]

A check valve is only useful for below water level installations (e.g. AG pools). It prevents the bucket from refilling when the pump is off.

However, for above water installations, the draw down should be much smaller with the pump off vs pump on.

What is the draw rate with the pump on vs off?

With a 1.5 HP pump, I would expect the suction to be much much higher with the pump on vs off so the draw rates should be a lot different.

However, if the chlorine buildup in the pump basket is too large when the pump is off, really the only solution is to dig a hole to lower the bucket.

My bucket bottom is close to water level and there is very little draw down when the pump is off.

 

[tcat]

Kind of what I guessed. Yes flow with on is much higher (although haven't put the needle valve in line yet). When I was playing with the ball valve the other day to get approx. 8 oz. per hour with pump on; I could still see the level going down with the pump off (probably close to the same rate since it's basically an air leak). I need to look closer at water level, a 12" deep hole could be a problem... how about a check valve with a set open force? Do they make something like that in plastic?

 

[mas985]

how about a check valve with a set open force? Do they make something like that in plastic?

You might check this out:
http://www.usplastic.com/catalog/item.aspx?itemid=24234

If the bucket is 12" above water level, then you would need one with a cracking pressure of about 0.5-1 PSI so the US plastics one should work but I am not sure about the chlorine crystal build up. It might need to be cleaned out periodically.

 

[tcat]

No problem after all. I only "thought" the water level was more than 12", but looking at my foundation around to the pump pad, the pad is about 3" above water level. I have a 6-9" deep rock landing around the pad, so I dug into the rocks, planted the bucket, and no more back flow! Will be tweaking my water flow and taking pictures next. Kind of nice, the chlorine will stay much cooler on hot day buried.

 

[mas985]

Let us know how it works out over time.

 

[tcat]

Couple of pictures of set up. Testing flow with water for now, getting under 32 oz per hour is tricky!

edit: Clorox is thicker than water! Makes it more difficult to tweak the valve, but think I have it. About 32oz. per my 4 hour pump cycle. So far FC hasn't gone below 6. The extra ball shut off is handy so you don't have to touch the needle valve. I can see why a Hayward needle valve would be worth the extra $$ if it has a finer adjustment.

Used sprinkler filter at end of tubing just in case (pink plastic coat hanger for support).

 

[tcat]

Update. So far a few days and all is well. Clorox level goes down 28-32 oz per day, FC stays between 6 and 7.

In the Orange bucket photo above, I used nylon cable ties to strap the tubing. The Clorox seems to weaken them, 3 were broken sitting at the bottom today. I replaced with larger ones, but does Clorox dissolve nylon?

 

[Bama Rambler]

Yes Chlorine attacks nylon. Try the black ones.

 

[AZHeat]

Aren't you concerned injecting liquid chlorine on the suction side directly into the pump. Normally you would want that after the equipment.

 

[mas985]

The chlorine is introduced at a extremely slow rate so it is highly diluted by the time it gets to the impeller. At most there is only a 1-2 ppm FC rise. No different than adding liquid CL to the pool and basically the same dilution ratios.

 

[tcat]

No concern here. At 32oz in 4hrs., that's less than a tablespoon a minute... into a 32oz. basket. I'd fell out safe at 10x that rate. Big test is when I'm on vacation for a week... soon to find out.

 

[tcat]

Follow up. Was off on vacation for 8 days.

Before:
FC = 4.5
pH = 7.6
TA= 80
CYA = 45-50
CH = 300

After:
FC = 3.5
pH = 7.8
TA= 80
CYA = 45-50
CH = 300

Clorox level in tank down 1.75 gallons. Getting hot here, so will try tweaking flow up about 1/64 of a turn. So nice not worrying about chemicals until the weekend!

 

[fiveclines]

Tcat,

Just wondering if your injection system is still working well. Might try to build one these for my in-law's AG pool.

 

[tcat]

I replaced my single speed motor with a 2 speed and had some issues on low speed, but I believe they are worked out. It's much harder to tweak the right feed rate on low, but I think I have it. FC ranges from 4-6 during the day with CYA of 40. My needle valve developed a crack and is temporarily "fixed" with teflon sealing compound. Not sure if I'm going to order another US plastics one for $10 or shell out the big bucks on a Hayward one (waiting to see if the teflon seal stays sealed)