Monday, August 24, 2009

Pool Fun

Once again the pool turned green right when the weather turned nasty-hot.

This has been the pattern for the last three years. I have no idea why suddenly I lost the ability to keep the pool water clean, healthy and crystal clear after more than five years with nil problems, but once it goes green - typically because I didn't have the chance to check it in daylight every single day and no-one else has the wit to do it for me - no amount of filtering will fix the problem. The best I can do is kill the algae that makes the water green, but getting the now milky water clear again is impossible, even if I run the filter 24 hours a day.

I long ago theorised that this was because the particles that make the water cloudy are simply too small for the cartridge filter to catch. I have added emulsifiers to the pool water to make the crud clump up, but I've had only marginal results afterward, with the water clearing a little but still looking cloudy at the end of the day.

Research on the matter of filters led to the idea I might switch the cartridge-type filter system with either a sand filter or a diatomaceous earth system.

Cartridges are relatively cheap and easy to maintain. They work like this: The water is drawn out of the pool through a slot in the side wall into a sort of can, about the size of a catering can of peaches (around10 inches in diameter and about 15 inches deep). The water passes through a mesh basket, which strains out the leaves, branches, footballs and canoes and enters the lower half of the "can" in which the filter cartridge is installed. The water passes through the filter and out of a pipe in the bottom of the can, travels through the pump and is returned to the pool by means of a jet in the side wall, rather like a jacuzzi jet. The pump works by means of a rapidly spinning turbine-like impeller that takes in water at the center of a disk with vanes on it that fling the water outward to the outlet at the rim. Very robust, very simple. Relatively cheap as I have said.

Sand filters work in much the same way, except that there's no filter cartridge in the "can" and the water passes from the skimmer to a second container, typically either a cylinder or a sphere which is filled with sand. Water is drawn through the porous levels of sand which catches the crud and holds it. Periodically you have to swich the pipes around and reverse the flow of water to backwash the filth out of the sand, but that's a job done on rare occasions. The filter system is quite a bit more expensive than the cartridge type, typically six to ten times so, but lasts "forever" (the sand never wears out but the pump will, eventually) and it catches particles down to about one tenth of the size that the cartridge filter will trap.

Diatomaceous earth filters are a breed apart. They typically work out initially a little cheaper than sand filters, but have a repeat cost (the diatomaceous earth) which the sand filters don't. They are arguably the most efficient type of filter, with a truly impressive dirt removal properties but the pipework and other infrastructure is a quantum leap sideways in complexity. The other types of filter may be tedious to connect up, but with a D.E. system we step firmly into Mousetrap Game plumbing and Engineering Smarts prerequisites. The water is drawn through the skimmer as before and then into a second sealed skimmer with a fine mesh basket intended to run entirely full of water. It possesses a clear lid so the lucky owner can check that a shark, log or bather isn't in danger of being sucked through the works. This is important because the D.E. filter works by positive pressure rather than negative pressure: the water must be forced through the filter rather than drawn through it. This means that the pump is situated before the filter itself. Water is drawn from the second skimmer and forced into the D.E. filter container, thence back to the pool as before. The whole system runs at around 10 p.s.i. so all the parts have to be firmly fastened down, fitted with O-ring seals and all threads must be well wound with teflon tape.

I had wanted one of these for years.

About three weeks ago I took advantage of a sale and landed a D.E. system for about $3001. I hadn't assembled it because of lack of time, but as though by prescient vision of the greenness-to-come I began to do so during the week the pool water mutinied.

It came as a kit.

Eight boxes, each containing up to thirty bits and pieces. It looked like a do-it-yourself nuclear reactor kit. Once I had emptied everything out of the boxes, my kitchen floor looked like the back of an octogenarian plumbing contractor's truck. Because there was the possibility of there being substitution of "equivalent" parts, fittings had been included for all of the possibilities. Or not, as it turned out.

The first problem was encountered about three seconds after the various pieces were laid out on the living room floor. The instruction leaflet made repeated reference throughout to various photographs to clarify this or that possible ambiguity in the "one-size-fits-all" instructions.

Unfortunately, these instructions had been reproduced on inexpensive copying equipment and the photographs were so dark that no details were discernable in them. It would perhaps have not been so bad if each component hadn't been black. Trying to scry out how a black thing mounted onto another black thing in a photograph that was pretty much a square of undifferentiated black was apparently all part of the fun of D.E. filter assembly. I ended up using the cartoon drawing in the sale flyer2 and even then was flummoxed.

The second problem was more prosaic. The motor was mounted on its own baseplate, but the filter components had to be assembled on a shared, larger baseplate. Although the instructions had a line drawing to "clarify" the process, there were no holes that would let me mate the small baseplate to the larger with the bolts supplied. Snarling some first-order Words of Power I got out Mr Socket Set and removed the motor from its baseplate and attempted to remount it on the filter baseplate, on which there were about a dozen variously-spaced pairs of holes to accommodate umpty-tump different models of motor.

None of them matched the motor I had in my kit.

Moving on to some second-order Words of Power I grabbed Mr Drill and made some holes that did match, then I attempted to bolt the motor down. The bolts that came with the motor were, of course, too short to do the job. The bolts that came with the baseplate were long enough, but too fat to go through the holes in the motor mount, which couldn't be safely widened. All retailers of bolts were now, of course, closed. Without hesitation I moved to Third-Order Words of Power and did the Dance of Rage. Then I gave up in disgust, had a shower and went to bed.

The next day I procured bolts of the right size and length and mounted the motor to the filter baseplate. Feeling particularly pleased with myself I attached the diatomaceous earth containment vessel, which made the thing actually begin to look like a filter.

But not much of one because after consulting the instructions I could now see I had the D.E. canister mounted backwards so it was time for The Bonehead Dance and some more third-order Words of Power. Once I had the damned filter canister on the right way round I called it a night and went for a lie down with a cold flannel over my face.

The next day I went back to the pool supply place and took a look at their display models in order to get some sort of clue as to which holes in the various bits had to be connected to each other or the pool itself, then returned home and installed some L-bends and the hose that connected the pump to the D.E. vessel, and the pressure gauge in the D.E. vessel lid. I was doing all right until I realised that although I had a scad of bits left over, none of them would supply the last hose fitting I needed in order to connect the filter assembly to the pool. This was the proper moment for some fourth-order Words of Power, so I used some up while punching the furniture and calling down all manner of plagues upon the head of the idiot who sold me an almost-complete filter kit.

The next day saw me back in the pool supply place to buy the missing part, and I was done! This was the signal for the pool to turn green.

Mrs Stevie was mad because she had scheduled a pool party for the Sunday and now it was looking like it wouldn't happen. I dumped a double load of shock into the wretched thing, connected the pump of the cartridge filter to the mains, bypassing the timer, and dumped a double load of emulsifiers into the damn thing for good measure. Then I connected up the pool robot of extreme uselessness and crossed my fingers.

By Friday, the pool was murky but not green, but on Saturday it had a relapse and Mrs Stevie used some fourth-order Words of Power, then decamped with The Stevieling for whatever they do when they've had enough of Chateau Stevie. I decided that I would finish up a couple of chores and then fit the D.E. filter system and let it have a go at the demon pool of greenness.

I finally got started at about 2 in the afternoon. The first thing was to fit two shut-off valves to the pool plumbing. Because the D.E. filter sits below the pool's water level it is important to be able to isolate the water pressure supplied by the pool when servicing the unit. This was, believe it or not, fairly straightforward even though the pool was currently filled to levels exceeding that of the places the shut off valves needed to be installed in.

I had previously bought a kit with a bunch of generic stoppers, sized for common sizes of fittings and used to winterize the pool, which I did one year instead if simply draining off the excess like I usually do. Using these and a free hand I was able to block the various holes left by unscrewed fittings for the time it took to install and close the valves.

I carried the new filter out and put it in place, and removed the old pump and filter cartridge. I connected up the device and bled out the trapped air. Everything was, worryingly, going without a hitch. This was a danger sign of no small magnitude. I rely on a steady stream of small problems and inconveniences in my jobs to bleed off the anti-handyman forces that otherwise build up and precipitate catastrophe at the worst possible moment.

The instructions called for 11/2 lbs of diatomaceous earth to be mixed in a bucket "to the consistency of pancake batter". This was a problem. I had no idea what pancake batter looked or felt like. I took a guess that it meant a sludge-like consistency and got out the postal scale, a couple of fast-food coke cups, and slit open the 25lb bag of diatomaceous earth.

On reflection I should probably have relocated outside for this bit, but I wasn't paying attention on account of fretting about where the inevitable killer problem was going to manifest.

It turns out that diatomaceous earth could just as accurately be described as White Soot. No sooner had I opened the bag than clouds of choking white powder erupted into the air, coating everything in a five-foot radius and almost killing me there and then. Measuring out this stuff produced more and more chalky clouds of annoyance. It got everywhere.

Eventually I had the stuff mixed up in the bucket and was able to start the motor and pour the sludge into the skimmer. It didn't seem to make much difference, but I left it running and went inside to clean up, just as Mrs Stevie returned.

"What in the name of all that's holy is going on here?" she demanded in her trademark menacing shriek.

I caught sight of myself in the mirror, noting the white powder lodged in my beard and moustache and daubed on my nose, and spotting the postal scale with its tell-tale small drifts of white powder lodged in every crevice. "It's not what it looks like" I said, defensively.

"It looks like you've been measuring out that filter stuff in my living room instead of outside where it belongs" she snarled.

"Okay, it is what it looks like", I said.

The conversation from that point became by turns abusive and very abusive, and I don't want to talk about it any more. Suffice to say I ended up once again lying down with a wet cloth over my head.

The next morning, Sunday, Pool Party Day, dawned and I looked out of the bathroom window. I was astounded. I could see every crease and fold in the pool liner. The water was clean. Not just clean-ish. Clean. Mrs Stevie, who was out of sorts on account of it being her birthday and the correct offerings had not yet been made, was passing by. I suggested she look at the pool. Her reaction assured me that we would have a good day after all.

This filter is the bestest thing ever.

  1. Quell snip!
  2. Of a different filter model but beggars, choosers etc

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