Yesterday was supposed to be the big pool-uncovering day, but it didn’t happen. The original plan was to open it early so I could get my coping project underway. But, yesterday it occurred to me that I could get started with the cover still on, and just pull the cover back to expose whatever area I happen to be working on. At that point it became a no-brainer: Leave the cover on for now and avoid the hassle of keeping the pool clean in late May when no one is using it.

I already had my help on the way over, so instead of uncovering the pool, we tackled the time-consuming job of scraping the old caulk out of the coping expansion joint. This was fairly easy to do with box-cutter type utility knives and plenty of sharp blades. However, on the decking side, it left a bit of residue because of the roughness of the concrete. I may try wirebrushing this area to get the last bit of caulk out.

Next up is to rent the big concrete saw and cut a true expansion joint (removing the caulk revealed that, as I expected, the joint is non-true around the entire perimeter of the pool). My current plan is to take a day off work and do it the week after Memorial Day. I’d like to get it done before my Vancouver trip; otherwise it’ll have to wait until June 10 at the earliest. Come to think of it, I suppose there’s nothing stopping me from doing it this week, either.. To deal with the dust, I’ll try duct-taping a tarp to the coping edge. With the cover still on, it’ll support the tarp and keep it from submerging. It might work.

I did my first water test yesterday, and surprisingly the numbers weren’t too bad: Free Cl 1.4, Combined Cl 0.2, pH 7.7, Alk 80, Hardness 170, CYA under 30. Water temperature was 63°. I’ll probably add some chlorine today.

After a winter of freedom from the big money-sucking hole in the back yard, I bit the bullet and fired up the pool pump today. Now, in the Mid-Atlantic, swimming season runs from roughly the beginning of June through Labor Day. If you’re lucky, you’ll get a couple extra weeks on either end, but for the most part, that’s what you get. For the past few years, my routine has been to start the equipment up around now, and uncover the pool around Memorial Day. I’ve found that starting the equipment early saves work, because it allows me to chlorinate the water before it gets too warm and algae starts taking hold. And with pools, anything that saves work is a bonus.

Anyways, the pump primed right up using the main drain for suction. The water level is still too low to use the skimmers. And the water temperature is (drumroll please) a balmy 56°F. Another 25 degrees and we’ll be swimming.

Now I need to start thinking about my spring pool project, repairing some loose coping and recaulking the expansion joint between the pool and the deck.

With electricity prices set to skyrocket in the Baltimore area this summer, I’m once again looking at ways to cut down on our consumption. And in the summer, one of our biggest consumers is the pool pump. I’ve read that a two-speed pool pump motor can cut down quite a bit on energy usage. A standard swimming pool pump runs at 3450 RPM. A two-speed pump can also run at half speed, or 1725 RPM. The interesting thing is, although it’s running at 50% of normal speed, a typical model draws less than half (about 30%) of the current that it would draw running at full speed. So in theory, you could run the pump at half speed for twice the length of a normal-speed run cycle, do the same amount of work, and use less power. Now, this might be wrong. I’m not well-versed enough in fluid dynamics to say whether, for instance, 10 hours at 1725 RPM would turn over the same amount of water as 5 hours at 3450 RPM. But, for the sake of argument, let’s assume it would. Running at low speed would certainly consume less power, and longer pump run cycles are good for the pool water because they keep it from stagnating (I’ve also heard anecdotal reports that sand filters “work better” with lower flow rates — take that for what it’s worth). Of course, that’s only one side of the story. There are also some caveats..

1. I can’t run the pump on low speed 100% of the time. I have a pressure-side pool cleaner (Polaris) with a booster pump, and I’d need to run at full speed while the cleaner was on (3 hours a day, 3 days a week or so). And, I’ll want to run on full speed for 3 hours or so after adding chemicals, to get them distributed as quickly as possible. Any time the pump is on high speed, it cuts into my potential savings.
2. The pump motors I’ve looked at all consume somewhat more current (1 amp or so on models I’ve looked at) on high speed, than equivalent single-speed motors. Not quite sure why this is, but it seems to be a fact of life.
3. Initial cost for a two-speed setup is high, even assuming I’m only replacing the motor and not the entire pump. The pump would need special wiring, and a new timer/control to control high vs low speed operation. Plus, I’d need a new shaft seal. I’m probably looking somewhere in the $350-$400 range when all is said and done.

A couple years back I made a spreadsheet to estimate potential savings using a two-speed pump, and concluded that the payback period was too long to justify the initial effort and expense, given what I was paying for electricity at the time. However, with the pending rate hike, it’s probably worthwhile to crunch those numbers again..