Peristaltic pump information moved from Chlorine forum

[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.

[fcfrey]

Steve,
Glad to hear your project is coming along.

I'll add this post on calibration of my system so you have an idea where to start.

Calibration of Peristaltic Pump:

First secure an accurate graduated cylinder > 200 ml and a stopwatch or other timing device so you can measure how much is being pumped over a period of time.

Start by dividing the speed control of the pump into equal divisions unless it has this done (mine did not). I then started the pump and counted the revolutions per minute and divided this by the number of lobes on the pump to determine how much is pumped per revolution or lobe cycle. Set the pump on each setting and time for 1 or 2 minutes recording how much is pumped.

Use these reading to figure the amount pumped in an hour. I created a spreadsheet to make my life easier. I then verified the calculations over an 8 hour period.

Using the bleach calculator I was able to figure out the PPM increase to expect for a given period of time (assuming no consumption from algae etc.). I did this at night to try to cancel the effects of solar burn off. I found I could predict the outcome accurately using this method.

The next thing I tried to do was calculate the PPM loss due to solar burn. This turned out to be a somewhat fruitless effort because of all the factors (clouds, date, water temp, pump run time, swimmer load, etc.) Needless to say I test very frequently (FAS-DPD method) and adjust the pump to keep the range within Ben's Best Guess Chart for my CYA level (around 22 ppm). After a period of time I was able to come up with some averages to work with.

I have since started increasing the CYA toward 30 ppm, to try to determine the best overall ratio. My daily CL burn off was about 2-4 ppm. if the pool is uncovered all day.

My experiment will continue for a year or two but things are favorable to this point. I may start looking at controllers if the price comes down but so far the cost/benefit ratio is still out of whack in my opinion. Any further questions --- please ask.

[nater]

Hey FC, I like your solar array! Very cool.

I use about 250' of black garden hose coiled up on the concrete when I need to add a few degrees. The BTU output on a hot and sunny South Carolina day is amazingly high....

Cool chlorine feeder as well. I love this home made McGyver stuff

[Steve #1]

Well, I got the pump and I'm not sure how it's going to work out. Rola-Chem had changed its model numbers and I couldn't find exact output for the pump I got, but it looked like it was the model for small to medium pools. Unfortunately its output is in line with there model for a large spa or for use as an acid pump for large pools. Output is 225 ML/Hr.

Based on my average consumption and normal pump run time, it should work for the most part.

I'm going to go ahead and set it up to see how it goes. If it can't keep up I'll just switch to a different pump.

[Steve #1]

OK, I'm set for everything except the electrical.

I got 2 60L (~16 Gal) chemical drums from work.

When buying tubbing, I was torn between clear vinyl and black vinyl. The black blocks UV, but would heat up more. I went with the clear since it was cheaper and plan to run it inside some 1/2" PVC I have on hand. This will reduce heat and UV exposure along with giving it some protection from dogs, kids, etc.

I am considering digging a hole and partly berrying the storage drum to reduce the effects of heat. The area where it will be is almost 100% shaded (between a shed and the house) so I haven't decided if it is worth the effort.

I had to buy a tap for my injector. I couldn't get a firm answer from either the hardware guy or the plumbing guy at Lowes if it was the right one or not. What I'm using as the injector is 1/4" MIP. The tap is 1/4" 18 NPT. After doing some research I'm 95% sure this is right, but I got a 1 1/2" PVC coupler to practice tapping just to be sure.

I should have this ready to go tonight.

I don't think it's much of an issue, but I'm going to order a check valve to install at the injector.

Now the electrical. The pool pump and booster pump are 240V and have intermatic timers. Ultimately these will be changed to connectors controlled by the home automation system, but that's down the road.

The Rola-chem pump doesn't have a normal flow rate adjustment. It has a timer that will run for a time (adjustable) then shut off for a time (relative to the run time).

I'd like to set up the injector pump so that it only has power when the pool pump is running. Is it possible (safely) to step down the 240 to 120 after the pump timer?

My other options for electrical are:
Running 140 from my bathroom vanity to the other side of the wall. Possible downsides to this are that the bathroom isn't on a GFCI (which should probably be updated anyway), and the outside wall is brick.

There is a switch and a timer for landscape lighting in the back corner of the yard. I have no idea where it runs from or what else is connected to it. I went to take look at it a bit ago and the ants informed me that it made a comfortable home, but agreed to move out.

Any opinions or criticisms are welcome.