Re: Peristaltic pump information moved from Chlorine forum
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.
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