I leave my pump running even when I'm in the plunge and I definitely feel it not letting me build up a heat barrier. Keep in mind that while you sit in the plunge the water temperature will start rising. This will cause my chiller to turn on but if you bypass the chiller it won't be able to offset the temp increase. This might not be an issue for you.

The smaller filter housings do restrict the flow quite a bit I believe. Here is a guy that did some testing: https://www.youtube.com/watch?v=UPiR30vWGaI
That's why I went with a whole house filter housing in order to not restrict it as much. But that could be pointless if the chiller is what's restricting it the most!

For measuring flow I filled a bucket to a known amount of water and timed it. I did it about 5 times and averaged it.

    wintermute

    I have a whole house filter as well. Since my setup is outdoors, I'm more likely to track junk into it.

    So I added this little screen that catches the big stuff. It works remarkably well and just kind of stays in place even when I shut the pump off. I'm really wondering whether the 20nm filtration is overkill, now.

        In my case I think the 20 micron is definitely overkill. I'm planning on replacing it with a less restrictive filter in the future. I can easily get in pretty clean every time with little risk of tracking debris in. Plus, it really does restrict the flow in my case:

        • Without Filter: ~540 GPH or ~9 GPM
        • With 20 micron filter: ~372 GPH or ~6 GPM

          wintermute

          You know what is funny about that flow test video in the link above? There was no filter in the housing! The only flow limiting factor was the geometry of the housing. And then the guy modified the housing based on that test.

          If you added the same filter to each housing, I bet you a dollar they were all about the same. The filter is the constraining factor in that case. The engineers who designed those filter housings surely knew that. They rightly had zero interest in optimizing the flow rate of the empty filter housing, since the filter itself is what sets the flow rate.

          But I digress… Would you have any interest in a bypass, where you could hit a button and bypass the filter and chiller, and turn off the chiller so no damage would occur? Would you want this behavior to be on a timer? Or a manual toggle switch? I'm wondering if I'm alone in this, or if I should craft something that is mass producible.

              laborde That's a really good point about the filter being the limiting factor. I wanted a bigger housing so I could get filters with more surface area.

              For me, I don't see a use case where I would want to bypass the filter and chiller.

                Did you use silicon or anything when you installed your bulkhead? I just tightened mine, and I have noticed that there is a very slow small leak coming from mine on the outside of the tub. I have tightened it so tight I'm almost afraid to tighten it anymore. I think I might have to reinstall it with some silicon caulking under the rubber gasket.

                  wintermute

                  I thought about it. Used to always use Permatex on engine gaskets so it seemed natural. But I shoved it in the hole I just drilled to see how it fit, and there it stayed. I did tighten it with some giant channel locks until the gasket bulged.

                  Since my setup is outside, I'm not sure if I would be able to detect a slow leak. There's just so much condensation.

                      laborde Ha, can relate. Mine loosened up over time, i might have screwed it on a bit too tight, the cooler indented a little bit, enough that I can feel it. So I redid it with some silicon.

                        10 days later

                        Hey @laborde did you make progress on this? Did you per chance do flow rate testing with the chiller? I'm so interested in that test.

                          wintermute I've been waiting for some kind of final word on ozone destroying the Grizzly coolers. The guys who sell the modplunge are saying they have done testing equivalent to running ozone for 10 years or something equally outlandish. When I asked about their methodology, they just ran a Jed into the tub 24/7 for a month. These things don't scale in linear fashion, so I don't have any faith in that test. Meanwhile, a guy in some of the Facebook groups has posted pics of cooler damage he thinks is from ozone. It seems to happen above the water line.

                          This weekend, I'll probably go ahead and disassemble, do flow tests, and reassemble with the venturi in place, but I'll probably not run ozone until I have more data.

                          Meanwhile, I have been using grocery store peroxide. Where do you get the strong stuff? I should probably pick up the 35% like you're using.

                              laborde I got the 35% H2O2 from http://bulkperoxide.com/ . There is also purehealthdiscounts.net and a few others I forgot. Thus far, I am perfectly content using just hydrogen peroxide at 100 ppm. That probably has a lot to do with me only getting in the tub after a shower.

                              I haven't seen anyone post ozone damage to the grizzly yet. If you're talking about the picture of all the tiny holes in the plastic I believe it came like that from the factory. If you saw something else, drop a link please!

                              I'm looking forward to your flow tests!

                                Thanks. I need to do some math, but it might be cheaper to use grocery store peroxide in greater quantity, since it is so cheap.

                                I've seen a couple of "tiny hole" pics. One guy insists that they weren't there when he got it, that they appeared only above the water line, and only after 3 weeks of ozone use.

                                Another guy posted similar pics and said his came that way. He had tiny holes both inside and outside the cooler.

                                So far, I put about 8oz grocery store peroxide in a couple weeks ago, and my month old water is clear and there's no slime on the walls. Like you, I shower before I plunge. I'm adding an outdoor shower right next to the Grizzly, so I can come from my barrel sauna directly, without going inside.

                                Looks like the stuff from the grocery is cheaper, but not by much.

                                35% peroxide at $65/gallon

                                $65 / (128oz x 35%) = 1.45 per oz of pure peroxide

                                $0.64 16oz HEB 3% peroxide

                                $0.64/ (16oz x 3%) = $1.33 per oz of pure peroxide

                                  laborde Good call on the outdoor shower!

                                  It doesn't make sense to me that ozone could cause those tiny holes. I would bet they were caused by a problem during manufacturing. I've seen many ozone degraded plastic and rubber components and usually it becomes brittle and starts cracking. Tiny hole person claimed it happened so fast, so time will tell in the next couple months after they start shipping with ozone generators.

                                  Good call on doing the math for the H2O2. I currently added 1 oz of 35% H2O2 to get to 100ppm. That would be equivalent to 11.7oz of 3% If I did the math right. So not much of an inconvenience.

                                    laborde not to butt into your conversation but I just bought a gallon of H202 from bulk peroxide. Use code welcomefam at checkout. It basically paid for my shipping cost.

                                      16 days later

                                      I did some flow testing last weekend. I measured the time to fill a 5 gallon bucket. In each case I ran the components listed, but through a 3/4" hose, back into the Grizzly. I'd let it run until the flow was steady, then move the hose to flow into the bucket. I was a little surprised by the findings:

                                      Pump + empty filter housing = 47s

                                      Pump + filter = 47s

                                      Pump + filter + chiller = 57s

                                      (5gal/47s) x 3600s/hr = 383 gallons per hour

                                      (5gal/57s) x 3600s/hr = 316 gallons per hour

                                      So, why was I surprised?

                                      1. Absent the chiller, I really expected the filter to be the main limiter of flow, but it was not. The freshly-rinsed month-old filter had literally no effect on the flow. I thought about removing/testing other components (like the Grizzly drain plug with hose adapter) but I had time constraints and moved on.

                                      2. I thought adding the chiller reduced the flow much more than it really did. It only dropped ~20%.

                                      3. This testing means to me that if I were to add ozone (unlikely at this point) I would add the venturi in parallel with the chiller rather than the filter. That would (a) bypass the tightest pinch point with a parallel path to create more suction in the venturi, and (b) increase the net flow. However, I had no slime or indications I need better sanitation. Grocery store peroxide every couple weeks seems to be more than enough in this cold, hermetically sealed system.

                                      I also identified a leak (just like @wintermute) at the bulkhead connection. I wiped a little silicone on both sides of the gasket and took care of that.

                                        So, here's v0.2. I tidied up some of the plumbing, put a mat under the chiller, added some steps with storage inside, and an outdoor shower.

                                          laborde Thanks for doing some tests! What is interesting is that for me testing with my filter and chiller but no filter in the housing I get 8-9 GPM which is much higher than you get even without the chiller. But you also have much more friction from fittings than I do.

                                          I like your setup, that is a really cool idea to have an outdoor shower.

                                          When you say you added silicon to your bulkhead gasket, did you use sealant or grease?

                                              wintermute I'm starting to appreciate that the plumbing is limiting flow quite a bit. I still think the chiller is the main limiter, though, and there's not much I'm willing to do about that. I could introduce a bypass valve to increase the net flow, but I'm not convinced it is worth the trouble.

                                              I used silicon sealant on the gasket. Worked like a charm!