Whoneedsavacation

I'm also using bromine floater system, with MPS spa shock twice a week.

I put these questions together because I'm curious about how much people's routines vary. You can critique me, too, if you like... What chemical system do you use? Bromine sanitization using tablets and a floater. How often do you test your water? Every day when things are new/changing and about every other day when they are stable. When do you test the water? How? Usually in the morning, we usually soak in the evening. I'm still using test strips, but considering a droplet reagent set. How often do you soak? Most evenings, sometimes after exercise during the day on the weekends. How often do you shock? What with? Twice a week. Spa-formulated MPS. How often do you drain and refill? We went about four months on our first fill and in retrospect that was way too long. Next time I'll do it as soon as I feel I want to take out stock in the anti-foam chemical company. I'd guess that was somewhere between 2 and 3 months.

Chem geek... for the record I'm letting the water sit at just below 80 TA and 7.6 pH and so far it seems very stable without any intervention. The experiment continues.

Well, for whatever reason, I'm having no trouble maintaining the free bromine level. Why it was runaway before the water change, I don't know. Having changed the water now, I can state with confidence that it had gotten really TIRED. It was definitely time for a refill.

If this is true.... This would not be true, modulo ineffciencies. It's not the physics but the engineering that makes the biggest difference here.

sure, BUT: Is not true because the difference between 80 degrees and 50 degrees Farenheit is not 40% in absolute units. dq is a much smaller fraction of q than that. And, even if the numbers were right, it would change by the same amount going down and up. You still don't win unless you "bottom out" for a while.

Here's sort of an analogy that might help people's thinking. It's not perfectly accurate physics but I think it is accurate in how it reflects the gross characteristics of the problem. The temperature of water is basically a measurement of how much heat energy is stored in the water. Your power cost is basically a measurement of how much electrical energy (or gas energy) you have used to keep the water "topped up" with that amount of heat energy. So you can think of the tub as a bucket full of a liquid that represents energy content. You want the bucket to be full to a specific level when you soak, the equivalent of 101 degrees Farenheit. But the bucket is leaky, so picture it as a bucket with a hole in the bottom. In order to keep the bucket full to the level you want, you have to put heat in at some point. So imagine you have a tank (your power budget) that holds a lot more energy than the leaky bucket that represents the hot tub. To make that leaky bucket full to the right level once a day, you have to pour energy from the tank in. You can either pour it in continuously at the same rate the water is leaking out of the bucket, or you can let the bucket drain dry and refill it whenever you want to use it. Let's say that the leak is at the rate of a half bucket per day. If you want to soak every day, you are putting the same amount of energy in no matter if you top off the energy constantly or all at once (unless, of course, you spill more energy while transferring it from the tank one way or the other.) If you soak every day, you have to put half a bucket of energy in every day and it costs you 7 x 0.5 = 3.5 buckets of energy a week. However, if you only want to soak once every four days, you will use far less of the energy in the tank by refilling the bucket only once every four days, because the bucket will empty out in two days and you can wait two more days before you need to take any energy out of the tank. This will cost you one bucket every four days, or an average rate of one-quarter bucket per day. This scenario costs 7 x 0.25 = 1.75 buckets of energy a week. If you soak every other day, you break even either way, because you are putting a bucket of water in as soon as it gets empty and it's one bucket every two days which comes out the same as the every-day figure. Of course, the truth is that the size of the leak in your bucket varies depending upon the model of hot tub, outside temperature, etc. etc. And the amount of energy you spill when you transfer energy from the tank to the bucket represents inefficiency in the heating system and that's also an unknown. So unless you go out and measure or otherwise determine what these figures are for your specific situation, you can't really decide offhand if you are going to save money one way or the other.

In LA-LA land it certainly is. Even during the winter, with gas heat running instead of electric A/C our gas bill is less than 1/3 of our electric bill. In the summer when we are just running the stove, dryer and hot water heater the gas bill is less than the average lunch. At any rate, it's the laws of physics plus the realities of engineering and a bit of economics that makes the difference as to what is the "best" choice. Sure if you let the tub go down to a steady state temperature and sit for a while, it will cost less. If you are adding heat back in as fast as you are letting it go, you probably accumulate more inefficiencies and it may actually cost more, but that will depend on the exact details of the engineering of your system. I don't want to have to plan ahead to soak, so we leave ours at a constant temp.

We shock regularly twice a week, with MPS, but not after every usage. We use the tub more often than not. But, yeah, I guess that affects the timescale for a steady state, too.

It probably mostly comes out in the wash, and the answer is going to depend on your cost of electricity, outside temperature and how well insulated the tub and cover are. I bet lowering the temperture 1 degree all the time would provide more savings that putting it up and down. TinyBubbles, isn't that mostly because a) gas is generally a lot cheaper than electric and gas heaters are usually more powerful so you can really wait until the last minute to heat the water, as with an on-demand hot water heater. Nominally you have to put the same amount of energy into the water to raise the temperature no matter what method you are using. However, the power used by the heater compared to the amount that actually goes to heating the water depends on the efficiency of the system.

Have you looked at the Freeflow spas? We have a Freeflow Passport, which was a fairly affordable tub in the size range you want and is convertible 110/220. We are quite happy with it.

If I understand it correctly, with Reserve and Renew you don't really develop a steady state level of free bromine as you do with a floater system. The bromine "bank" you establish with the Reserve is the same sodium bromide you use to start up a "regular" bromine tub and doesn't test as free bromine. You use the shock (Renew) to create the actual sanitizer (hypobromous acid) and I guess that probably creates free bromine temporarily until it is used up. So I'm guessing your experience is normal. Chem Geek, where are you when we need you?

Prepare to be patient. We just went through this and it took several hours for the tub to drain. We have a long run of hose to the street and while it is mostly downhill, it definitely seemed to slow things down. It's supposed to drain 5 gallons per minute, and should have taken only about an hour and 15 minutes to drain, but it took MUCH longer. We used a couple of towels to bail out the last bits of visible water and didn't worry about the remainder in the lines. Make sure you know what you need to do with the chemistry at refill time. Don't laugh, but read the instructions. Our tub has a fairly nifty drain valve, but it wasn't completely obvious that the right procedure was to pull the valve out, twist it, pull it out some more and then attach the hose and push it back in halfway.

We are currently running our Freeflow Passport on a 110v circuit. Our recent drain & refill experience has us seriously considering upgrading to 220v before we go through that again. For one thing, it took over 24 hours for the water to get above body temperature and it isn't even that cold here. For another, we discovered experimentally that our 1950s house has the porch outlets (where the tub is), the kitchen appliances and the washer and dryer all on the same circuit! I blew the breaker while cleaning the fridge out -- it cycled on because I had the door open, the washing machine was running and we had no idea the tub was on the same circuit as well! So the tub is fully convertible, we just need to open the panel up and throw a dipswitch once the electrical work is done. We may have some work done on the panel and subpanel as well since we've also blown breakers with a hairdryer and vacuum running at the same time. Since the 220 will be pulled specifically for the tub, it will then have a dedicated circuit. Is there anything else, aside from hiring a good electrician, we should consider in regard to the tub itself? It is sitting outside on cement slab under a partial cover ("ramada"). I'm tempted by some kind of outdoor towel warmer as the weather gets colder, not that we get COLD here very often.

I started with the sodium bromide, yes. Both times. But my understanding is that that establishes a "bromine bank" and won't test as free bromine. I can easily reduce the amount of free bromine to zero by taking out the dispenser for a couple of days, but I prefer not to do that as I'm not a fan of cloudy, ucky water... so I want to ramp back gradually and leave enough time between adjustments to be fairly sure of a steady state. How much time IS that?

OK, I'm happy with my water balance on my new fill, but I'm still having trouble keeping the free bromine at a low, controlled level (2-6 ppm). How long does it take for one mini-bromine-tab worth of chemical to react in a 375 gallon tub which is covered during the day and used for about 30 minutes every evening (after dark)? I am asking because after about 15 hours with the floater loaded with tablets and set where it had been previously, there was no measurable free bromine, so I dropped 2 tabs in the filter well to get the level bootstrapped up. Now it's around 10 ppm and has been for about 24 hours. How long should I wait before I decide the feeder has developed a steady-state and it is time to close it down some more? It's the design of feeder that stacks the tabs vertically and has a screw adjustment with a locking ring to limit surface area exposed pretty reliably. Or do I need to take the thing out for a certain period of time and put it back when the level is where I'd like it to stay?

Certainly nice to have a competent amateur chemist in the house!

Actually my see-saw went the other way around. First the TA drifted down, but correcting it with baking soda caused the pH to go up enough that it was out of range. Adding dry acid just caused both to come back down, admittedly the pH came down faster than the TA, but it was still difficult to get both "correct". So... if my pH stays where I want it, there is no need to try to adjust the TA unless it goes below 50? I think I may have shot myself in the foot on the last fill! I kept reading "Adjust the TA first, then the pH" so I aimed to get the TA over 80ppm before even thinking about the pH.

I enjoy soaking commando when it is dark out and I don't have to worry too much about neighbors peering through the fence, but I'd never ask my guests to either disrobe in front of me or to view me disrobed. If my friends happened to be members of the same nudist camp, I might feel differently about it, but that's pushing friendship a bit too far IMHO. And kids... no way. Not someone else's kids in my tub. Suits don't need to cause foam -- don't wash them with soap often. I bet personal care products cause more foam than swimsuits.

I also find I have to perch a bit in the lounge seat to avoid floating, and I'm just sinkable enough to relax without floating in the more upright seating spots. I do enjoy free floating some of the time, BUT, I'm looking forward to the decrease in buoyancy that will come when I finally commit to taking the pounds that have been creeping on over time off. I'm adding that to my list of motivations. I'm 5'7" and I'm darned sure it is the 40 extra pounds not my overall size that's the problem. I know I was less buoyant when I was thinner and very fit. Fat is less dense than water... I'm guessing that really light people without a lot of muscle tone might also tend to float. So if you are a small person and a floater, lifting weights might help!

I don't think the foam down products affect water quality too much. I had to order Calcium Booster (the Leisure Time brand) online as none of the local pool supply stores seemed to carry it. I can't believe I'm the only one around here to have soft water! It made rather little difference in the foaming though.

I think I should do it more often! I'm going to print that out and put it with my "chemistry set" aka spa supply shelf. So it sounds as if I have been doing the right thing for the most part. I just did a refill and right now the TA and Ph are both in the optimal range without any adjustment. On the last fill I found myself constantly adding tons of baking soda to try to get the TA up, and then pouring in tons of (dissolved) dry acid to get the PH back down, with the result that I was almost always in a state of low TA or high Ph. (Well, actually the water was. I was in a state of high anxiety!) If I understood the chem 101 lesson, unless there are better PH down products, that's the best I can do. Right? (We're on a bromine sanitization system FWIW).

Can you give a quick Chem 101 on why sodium bicarbonate is preferred to raise TA and sodium carbonate is preferred to raise PH? Presumably both have both effects to a large extent.

Weeel, I had read that low hardness encourages foaming and I ordered a calcium hardness increaser online to raise it. I succeeded in improving the test reading, but it didn't affect the foam very much. When is the last time you rinsed your filter? Since I've been doing that more often, the foaming has been less pronounced.

What about the bromine bank & shock approach rather than using constant-feed tablets? Any experience there?