The purpose of a flow meters and the flow rate for a float tank – DSP 87

When navigating demands from health departments, it can be an absolute minefield of regulation, oftentimes with holdovers from the pool and spa industries. Many of these can be superfluous to float centers, but if you’re just starting a center, it’s difficult to know which ones to ignore, and which ones to incorporate.

Flow meters fall into this weird gray area where they’re not as important for float centers as for pools (and in some cases aren’t really needed at all), but can still be required by health departments or regulators. And to not throw the baby out with the salty bathwater, there are definitely some very practical uses for flow meters on float tanks.

Graham and Ashkahn tackle all these confusing elements and even provide specific product recommendations for flow meters for float tanks. Give it a listen!

H2Flow’s Flowvis Product Page (the “FV-C-Saline” is the model specifically for float tanks. Scroll down on this page to find specific mention of it.)

Listen to Just the Audio

Transcription of this episode… (in case you prefer reading)

Graham: Today’s question is “My float tank came without a flow meter on it. Are they important?”

Ashkhan: Oh yeah. I got a lot to say about flow meters.

Graham: Yeah, me too, so I guess we are going to have to fight over this one.

Ashkhan: Okay. So what is a flow meter?

Graham: Okay. What’s a flow meter? It is a meter designed to measure the flow of solution through your filtration system.

Ashkhan: Yeah, so usually you hear this about your pump, its rated to do whatever, 50 gallons per minute, 40 gallons per minute, something like that, so why is it important?

Graham: I guess, so let’s back up a little bit, so your pump is rated for a certain amount, and there’s also this idea of ideal flow that you’d get if this thing was just shooting directly in whatever it’s shooting into versus what actually happens, which is you have to calculate this whole dynamic head and figure out what the flow is.

Ashkhan: Which is why it’s important, so I will say a few things first that I don’t think every system needs a flow meter. Specifically, I don’t think systems with reservoir systems need a flow meter.

Graham: Sure.

Ashkhan: Because really, you’re being concern about flow has to do with turnovers. You’re going through this idea of doing a certain amount of turnovers between each flow, and your flow meter is telling you what the flow is, and that’s how you know you’re doing the turnovers that you are supposed to be doing. That’s kind of the concept.

And I think some things that are interesting to know is that if you were to be running a pool or something like that, a commercial pool, you’d definitely have a flow meter on it. It’s usually required legally, when an inspector comes, it’s one of the first things they are checking is your flow meter. I will say there’s some distinction between the necessity of it on a pool versus a float tank, and into my mind that comes in part because of the fact, that float tanks are kind of identical units that are manufactured as a unit.

When someone goes and builds a commercial pool they are building it into that spot, and they’re working with that area, and they’re doing all that sort of stuff, and so once they’ve built everything, they want to have a flow meter to make sure that everything’s going a certain speed and everything’s working correctly, whereas on a float tank if a manufacturer is doing something where the piping is the same, and their filtration system os the same, and everything is pretty much the same as it is in their factory where they’re making it, they should be able to test the flow there and that’s going to be representative of the flow that it’s going to be doing in your place.

Graham: And so, the problem there with that, even if they have a really nice flow meter, and they are getting accurately is, what if your pump system gets gummed up?

Ashkhan: Right.

Graham: Or if something is getting in the way of that flow, you’re not going to know unless you have a meter on your own tank.

Ashkhan: Yeah, so that’s why we really like flow meters. We’ll put them onto float tanks that we have that don’t have them afterwards ourselves. And that is one of the nice things, it’s one of the easiest things to add to your filtration system yourself, which is nice. It’s not anywhere as hard as changing the pump that came with your float tank or a filter or anything like that. Adding a flow meter on, you usually just requires cutting off the right chunk of pipe and putting it on in place of that, so it’s nice, we check our flow every morning, and it’s just to make sure things are operating correctly.

What can happen is if you got a bunch of hair caught up in your strainer basket on your pump or your impeller or something like that, you’re going to see that on your flow meter. It’s going to … you’re going to come in one morning and all of a sudden the flow is going to be five, ten gallons per minute less than it normally is when you go check it, and for us it’s just a really nice way to make sure that everything is at least operating a certain amount of normal, really fast, just by looking at this one thing, and checking the number on it.

Graham: Yep. I mean, you can even catch when something’s going horribly wrong and all of a sudden it’s down at 10 gallons per minute, and something is seriously … It’s like actually just shoved up against the suction on the tank or there’s all kinds of problems and just really quickly being able to check your flow can … Although you’ll hear before it causes serious damage to your equipment, because often times if your flow is a lot less than you are expecting it’s because something’s going horribly wrong and it’s about to go worse if you don’t fix it.

Ashkhan: And most of the time it’s hair stuck somewhere. That’s almost always what it is, hair stuck somewhere, and you’ve got to go deal with it, but I should say though that you don’t actually need a flow meter to do this, there are ways to calculate this without having a flow meter, and there’s ways to do it kind of theoretically with no additional equipment which is what Graham was talking about the kind of total dynamic head where you measure your pipe length and back pressure and all of that sort of stuff and you get a number and you base it off your pump curve… I don’t know, all of that to me is a little too theoretical to use practically.

And then there’s the method where, if you have the ability to measure pressure before and after your pump, there’re calculations you can use that just take those pressure readings pump them into a calculation and it will tell you what your flow rate is, but you need to have the pressure sensor or the psi kind of readers in the right place on your system, so there’s some equipments in that scenario as well.

So the flow meter is not the only way to accomplish this goal, but I find it to be the easiest because it’s literally just the thing that just reads the flow back to you.

Graham: I’ve known centers too that measure it especially when the system’s first installed, they kind of pass their health department inspection without having a flow meter of just actually doing a five gallon bucket test, so opening up a part of their spa pack basically and having the water flow into a five gallon bucket and timing how fast it takes to fill up that five gallon bucket and then doing some math to figure out the flow.

And I know at least one place that does that every time their health department comes in, because the health department needs to know the flow rate-

Ashkhan: So yeah.

Graham: So they do this bucket test every single time and just okay, take it off, measure how long it takes to fill this up, you’re good to go.

Ashkhan: That’s crazy. I mean that’s another thing to consider, some health departments just require flow meters, and you’re going to want to have one.

Graham: Yeah, and honestly, I think that’s the biggest reason people end up asking questions like today’s, like “are these important? My health department’s saying that I need one.”

Ashkhan: Yeah, so to summarize I would say that they’re not as important as they are in a pool for a few reasons although I still really like having them, and I enjoy being able to look at them while we we run our float center.

Graham: Pet them.

Ashkhan: Nice, yeah.

Graham: Take them out to a nice dinner occasionally.

Ashkhan: Put tiny bow tie on them.

And the reason that you were saying before that I don’t think it’s important for a reservoir system is because you really don’t care about turnover in the reservoir, you just need the water to go into the-

Graham: It doesn’t really matter how fast it goes. Everything is passing through the filtration system so …

Ashkhan: Right. So the flow rate doesn’t really matter, and you don’t really need to measure it and … Although you could, I guess it could still be nice just to know if somethings unusual right?

Graham: Yeah.

Ashkhan: But you could I guess just time , you could just time how long it takes, so I don’t know. Way way less important in my mind in reservoir system.

Graham: So there are right and wrong flow meters to use for the float tanks?

Ashkhan: Yeah.

Graham: And we know one right one, and we know that there are a lot of wrong ones out there, but beyond that, I don’t have ton of answers.

Ashkhan: I guess it’s more because we know that the right one had to be made to be right.

Graham: Yeah. We have a strong suspicion that there are-

Ashkhan: Yeah, it makes me skeptical of all the other ones.

Graham: Very few to none that are out there that haven’t been made of float tanks.

Ashkhan: Theoretically. Yeah.

Graham: Well just again yeah … Skeptical.

Ashkhan: Skeptical.

So yeah so I mean, and this was … The company is H2Flow, and this guy was making these things called the Flowviz, is the name of the product, the flow meters, and a lot of float tanks were using them, and I think he realized that all these float tanks were buying his flow meter and he was wondering, ” Hey, are these things actually accurate with the salt, the density of liquid going through there?”, and so he tested it and finds out in fact they are not accurate with the salt water, which is a very common story you find with equipment being used on float tanks.

Graham: Yeah. Like every piece of equipment ever. Yeah.

Ashkhan: But they go further H2Flow and actually make a float tank specific flow meter so it’s actually calibrated to float tanks. It’s calibrated I think for 1.26 specific gravity I want to say, but I might be wrong about that. It might be slightly different, so just know that it’s still, if you’re at a different specific gravity then it’s calibrated for it will still be a little bit off but it won’t be nearly as off as a just like the non-float tank ones that they were making.

Graham: Yep, and it’s not a linear scale so it’s not just a one to one of it’s always off by this amount-

Ashkhan: Yeah, you can’t just knock ten off or something-

Graham: Kinda goes on a little bit of a curve, but that was about what it is right? Is that a lot of the flow meters are overstating their flow.

Ashkhan: Yeah.

Graham: So when you actually find out the float tank’s specific one on there, your flow is going to read less if you haven’t used that previously and we found by about 10 gallons a minute or sometimes a little more than that.

Ashkhan: At around the speeds they were doing. Yeah.

Graham: Yeah. Exactly. Yeah.

Ashkhan: You work from five to ten gallons per minute-

Graham At around 50 to 70 gallons a minute that’s decreasing by about 10 or so-

Ashkhan: Yeah, so the float tanks specific one is on their website where you can email them. I almost forget the letter it’s like flowviz ‘S’ I think for “saline”.

Graham: Yeah.

Ashkhan: So , definitely, if you’re going to add a flow meter, it’s the one I’d recommend getting.

Graham: So there you have it. We think they’re important, but they’re certainly not 100% necessary unless you’re required to have them which case you’d rather, they’re necessary.

Ashkhan: Okie dokie. Well, You guys have other questions, hope on over to floattanksolutions.com/podcast, and we’ll talk about them.

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