Peristaltic pump information moved from Chlorine forum

[Steve #1]

fcfrey,
What would it take to get you to do a full "how to" on your setup?

I'm wanting to do something similar. I'm pretty handy, but this is a little out of my realm. The only "how to" I've been able to find is this one. While it is very detailed, I'd still like some other ideas for a good setup.

I'm planing on doing this next spring, so I have a little time to work things out. I first have to install the ELK M1G alarm/automation system that will eventually control the pool pumps and chlorine injection etc......

(sorry for hijacking the thread, just wanted to be sure this was seen)

[fcfrey]

I have read, printed, and even called Mr. Kinch about his system. He uses ORP sensors, and a computer running Linux to control his system. Mine is not nearly that sophisticated. My pool manager (Wife) tests daily and adjusts the speed of the pump just like she did when we used an erosion feeder and pucks (before we got educated (here)).

I considered probes and controller but the technology is not what I think it should be and the equipment is not cheap. I tried a bunch of different probes (see my old posts) and had poor results.

I'm more than willing to do a "how to", but it will have to be somewhere else (not in this thread or forum) --- Possibly in the Chlorine Feeder, Off Topic or China Shop. I'll leave that up to the moderators. It may be better to do it privately.

Another consideration is the multitude of different arrangements in plumbing and systems. I know how mine works down to the pump curves and insulation on the pipes. Having someone follow my directions and mess the whole system up could be disastrous and obviously I am not willing to accept any liability.

AL, Janet, Carl, Watermom ----- your decision. Perhaps you would want to move the last couple posts too ---- I don't care.

[Steve #1]

I'm not planing on going all out with sensors and such.

Using the ELK to control the injection, I can find a good ball park for an average day and either manually adjust it (by computer) from there as needed, or, if i do decide to go all out, make some complex rules to automatically compensate for amount of sunlight etc., but I still think this would just help with keeping me in the ball park.

I'm curious as to what to look for in a pump, and how to plumb it to avoid back flow and such. Suggestions on storage tanks would be nice too.

Don't worry about me holding you liable if something you say doesn't work for me, I know I'm perfectly capable of screwing things up on my own. I'm just looking for ideas for my setup.

[fcfrey]

I'll take this a bite at a time so those who are interested can follow. First let me say I am still in the experimental stage. I am still learning so take those things under advisement (this could end up a total flop).

Here goes----

Several things must be determined before you go shopping for the parts and pieces you will need.

First you must know how much liquid chlorine your pool uses during peak periods. You will also need to know the minimum flow needed to maintain a given PPM in your pool.

Your purchase of a pump hinges on these two values, assuming you intend to run the injection system while your circulating pump is running. I circulate mainly during the day and try to keep up with solar burn off. A lot of pool owners use a different philosophy but........ Since there is no burn off and I don't have algae eating the chlorine --- I give the system a rest at night. Choose a pump that gives you what you need in terms of Gallons per DAY minimum and maximum.

Of course you need to be able to test the pool accurately and since I do not believe the labels on the bleach containers, I test each batch I buy. I use the FAS-DPD method using the 25ml sample size when sampling the pool and the bleach batches.

Sampling the bleach is an extra, but until you know how much of what concentration you are feeding it becomes a guessing game if you don't.

My method for sampling my injection solution is as follows:
Using a 1000ml volumetric flask -- fill to 1000 ml with well water or distilled water. Then add .10 ml of the solution mix and test using the FAS-DPD method (the result in ppm equals the percentage in the concentrated solution). I use a syringe from the drug store that is used for the TB mantoux test. It is graduated in .01 ml to 1 ml max -- but any syringe you can get that allows you to accurately measure .1 ml accurately will work.

As mentioned above I used a pump that I purchased from W.W. Grainger. The pump is a Mec-O-Matic VSP-20. It fit my needs, included the injection fitting with check valve , tubing and suction line strainer plus it was not very expensive (< $200). I must say there are better pumps out there (look at Stenner pumps) which are weather proof (Mine is NOT so I had to build a weather resistant box to put it in).

The tank was separate and is also available from Grainger in 7 or 15 gallon size. You need a tank that will hold at least a couple days of solution, is opaque, chemical resistant, and has a large fill cap. It needs to hold enough solution so you don't have to be messing with it all the time, which brings me back to determining what your needs are and what concentration you want to feed. Obviously feeding 12.5% bleach takes a lower flow to do the job but also breaks down faster in the tank if it lingers there too long. I am current using 3% (diluting what I buy as appropriate).

I have been testing the solution when I fill and then again when the tank is just about empty. I do this to see how well it is holding up under the conditions that are present (not in the shade or a cool place) --- so far I have not experienced any significant degradation of my solution which is mixed with pool water (but it isn't summer yet!!). There is a bit of CYA (25ppm) in the pool water but I doubt if it has any effect on the stabilization of the solution. At a feed rate of ~60 oz/hour [3%] running 10 hour per day, you find that to be about a 3 and a half days per tank full (I expect this to change and may have to go to 6% bleach as the demands rise).

That about sums up the prerequisites. If you haven't downloaded the Bleach Calculator DO SO NOW --- You're going to need it!!. Also, search on my old posts and also those from "Hamop78" (I used a lot of his ideas)--You will see a lot of information from Richard (Chem Geek) and others on the subject. --- I'll get into installation next time.

[fcfrey]

Now for some of the installation. A storm is coming so it may be short.

Hooking up the plumbing is pretty straightforward. The peristaltic pump, by its very nature will not back feed. In addition the injection port I used has a "Pop-it" type check valve built in. It works by actually requiring a greater pressure from the pump than on the other side in order to open and since it only goes one way it acts as a check valve. If the tubing comes loose or breaks the only consequence will be to pump the injection solution on to the ground at the rate the pump is set for.

Installing the port was only challenging because I wanted to locate it as far away from the other systems as possible. Definitely as far downstream of other chemical feed devises (erosion feeders etc,). I also wanted it to be out of the way so the port didn't get damaged. The port was 1/4 inch male pipe thread so I had to drill a hole of the proper size to accept the 1/4" pipe tap, in this case that drill size is 7/16". I also chose a location where I had multiple layers of PVC pipe to drill through (actually 3 fitting thickness). This gave a broad surface to tap and seal with Teflon tape.

The tubing to the pump and tank was just a matter of hooking up the tubing.
The only caution is to hook the tubing up to the proper sides (in and out).

Your local building code may require you to have a licensed electrician do the electrical work. Check the code in your area!!

The electrical was only challenging because everything beyond the breaker box at pool side is 220 VAC 2 wire with a ground. The pump was 110 VAC so there had to be a neutral. I have to preach a bit of National Electrical Code at this point. I'm not yelling but ----- NEUTRAL IS NOT GROUND. YOU MUST HAVE A NEUTRAL AND A GROUND. In addition NEC mandates NO OUTLETS WITHIN 10 FEET of the pool. I wanted to be able to unplug the pump and remove it for the winter and had the 10 feet from pool side. NEC also dictates these type things must be on a Ground Fault Circuit Interrupter (GFCI) breaker. This could be a problem if your pump is not on a GFCI (I installed a GFCI breaker on the main line at the house when I put the pool in so I was covered on that aspect. Things become a lot more complicated if you don't have the proper electrical facilities available. I'll explain how to overcome these obstacles if someone cares.

I had to pull a neutral from the box to the peristaltic pump outlet. I used one side of the pump feed after the last switch in the circuit so that the only time the peristaltic pump runs is when the pool circulating pump is running. This avoids building up a concentration of bleach in the return line. There is a switch on the peristaltic pump just in case you want to it shut off.

That's about it for installation so now it's Q&A time.

Next installment I'll touch on calibration and operation.

[Steve #1]

Plumbing the pump sounds easy enough.

I'm glad you pointed out the electrical side. I'll have to take a closer look at what I have there. I'm pretty good with low voltage DC but not so good with the household stuff. I'm going to switch the main pump and booster bump from using timers to connectors at the same time I do the injection. I'll probably get someone with more experience to help me with the electrical.

[Steve #1]

Well, it looks like this is coming together faster than I expected. I'm getting a 20-25 gal chemical drum from work, and Just picked up a Rola-Chem peristaltic chlorine pump on ebay for $32 shipped. Go figure, I finally find a great deal on a pump and it just so happens to be specifically for what I'm doing. I'm going to wait to see what all comes along with the pump before getting anything else, but worse case, I'll need a check valve, injector, and some tubing.