Fruddled Gruntbugglies

Category: Pool

  • Hump Day Ramblings

    Hump Day Ramblings

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    I accidentally shut down my X server yesterday before I left work, so I took the opportunity to install the custom nVidia driver on my X desktop. And I must say, the proprietary driver is much nicer than the nv driver that comes with X.org. Someone at nVidia has put a lot of work into making these cards work well with Linux. The installer script produced a working config file that started right up, with acceleration enabled to boot.

    The nVidia driver has a built-in option called “TwinView” which provides multihead support via the VGA and DVI ports on the card. It replaces Xinerama, although supposedly Xinerama can still be used to provide the same functionality. However, TwinView seems to be the better alternative because it provides acceleration on both displays. It also adds Xinerama-compatible “hints” to the X server so that window managers will work the same as with Xinerama. It’s really very well done. So now I have a full 24-bit display across both monitors, with acceleration. Right now I’m still using the widescreen as my “main” display and the standard display as my “secondary” screen. I’m going to try it like this for a while, and if I don’t like it, I’ll switch them.

    The only configuration challenge was getting both displays working at their respective resolutions. I accomplished this with the following Device section:

    Section "Device"
Identifier "nVidia"
Driver     "nvidia"
BusID      "PCI:1:0:0"
Option     "TwinView"
Option     "MetaModes" "CRT-0: 1680x1050, DFP-0: 1280x1024"
Option     "TwinViewOrientation" "RightOf"
EndSection

    The MetaModes line is the important one.

    [More:]

    While testing things out, I also learned something about VNC: It compresses the pixel depth over slow connections. To force full-color rendering, I need to do

    vncviewer -FullColor host.name:display

    I was initially scratching my head as to why it was still rendering limited colors despite the 24-bit display. That explains it, and I may want to keep full color rendering disabled to maximize performance over my slow DSL uplink.

    Also, this morning I hooked a scavenged SCSI disk up to my PC at home, mainly as a proof-of-concept: The disk uses 68-pin wide SCSI, and my controller uses 50-pin narrow SCSI. However, all I needed to make it work was a 50-to-68-pin adapter cable. I just jumpered the drive to SCSI ID 1 and plugged it in. Initially I had an external terminator on the drive case, and that hosed things. When I removed the terminator, it worked. Apparently my controller wants to terminate the bus itself. At any rate, now I have a spare 72-gig drive with its own case and power supply.

    And finally, what’s a summer blog entry without a mention of the pool? Last week, the backup valve on my Polaris 380 broke. The valve mechanism itself is a big mess of gears and turbines, which fits into a plastic enclosure. The enclosure is made up of two halves held together by a screw-on collar ring, with a couple of o-rings to prevent leaks. The screw-on collar piece is what actually broke, probably after the valve was dropped onto the concrete pool deck one too many times. The mechanism itself was undamaged. Fortunately, Polaris sells a replacement case kit separately, and it’s much less expensive than an entire valve. The annoying thing is, the case kit only includes one of the two necessary o-rings. The included o-ring seals the two case halves together. The other one seals the backup jet to the case. It’s “technically” not part of the case, but if I’ve got the valve disassembled anyhow, I might as well replace both o-rings as they’re both probably worn out. It’s a small o-ring (1/2″ O.D. x 3/8″ I.D.) and it would have been nice if Polaris had seen fit to throw one in with the case kit. Oh well. For future reference, I found a replacement o-ring at Home Depot, in the plumbing section where they have the faucet repair kits.

    Well, I guess I should get to work now.

  • Troubleshooting cloudy pool water

    Troubleshooting cloudy pool water

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    For the past several years of pool ownership, I’ve always had off-and-on problems with cloudy water. I’m generally pretty good at keeping up with the water chemistry, so I’ve always been a bit curious as to why the water clouds up so regularly. The pattern is the same every year: it starts out crystal clear, then after a month or so, the water slowly starts getting hazy.

    The only way to get to the bottom of this is to apply the scientific method: assume that the problem is caused by x, try a known solution for x, and see if it works. I’ve worked at this over the past few seasons, and I’ve come up with three potential causes.

    [More:]

    Problem: Yellow algae
    Cause: Lack of superchlorination

    Yellow (or brown) algae presents as a fine “dirt-like” substance that accumulates on surfaces. When brushed, it dissipates easily and clouds up the water. It re-settles when the pump is off. I had big problems with yellow algae last year and the year before. At the time, I was superchlorinating very infrequently (only one or two times a season). This year, I have been superchlorinating weekly and also using a polyquat type algaecide semi-regularly, and I have not had an algae problem (yet). If this is the ticket to keeping it at bay, then I need to figure out the ideal frequency of superchlorination that will prevent algae blooms without wasting too much chlorine.

    Problem: High pH
    Cause: Prolonged use of hypochlorite sanitizers without adding acid to compensate

    High pH and/or Alkalinity can cause cloudy water. Once this year I let the pH drift to almost 8, and the water was noticeably turbid. Adding acid cleared it up after 12 hours or so. I’ve found that supplementing the hypochlorite with a trichlor floater (in moderation, to avoid high levels of cyanuric acid) can help to keep the pH down, particularly during the hot months when the chlorine demand is high.

    Problem: Inadequate filtration
    Cause: Undersized pump and/or not running pump long enough

    I’ll freely admit to running the pump as infrequently as I can get away with it, to try to save electricity. Unfortunately it appears that I’m paying the price for this in the form of cloudy water. Currently, the pump runs around 9 hours a day (6 hours in daylight and 3 hours after dark). With turbid water, a pH of 7.4 and no visible algae, I ran the pump for 24 hours straight and there was a marked improvement in clarity. So it appears that I need more circulation. This seems odd to me, because 9 hours really should be enough to fully turn the water over and keep it from clouding up. So I’m curious if my pump and/or filtration system is undersized. When I get around to it, I’ll measure my flow rate and see what kind of numbers I’m getting. If they’re low, I may want to consider a larger pump and/or filter. Until then, I guess I’m stuck running the pump longer if I want clear water.

  • Mortar for pool coping stones

    Mortar for pool coping stones

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    I swung by Lowes today to see what kind of mortar (and mortar ingredients) they carry. Neither they nor Home Depot seem to carry white Portland cement, so unless I go through a supplier or lumber yard, it looks like my only choice is gray mortar. However, I’m not sure that’s such a bad thing. Most of the stuff is going underneath the stones, where it won’t be seen. Gray Portland is cheaper than white Portland. What about using gray mortar to bond the stones, then filling in the gaps and other visible areas with white grout? That might be a plan. I just need to look into what kind of “grout” (I put that in quotes, because grout, mortar, etc. all seem to be basically the same thing, namely portland cement, sand, and additives in varying ratios) I would need to get.

    Lowes carrys Quikrete products (Home Depot carries Sakrete). They have a bewildering variety of different Quikrete products on the shelf…

    [More:]

    Number Description Bag Weight Bag Price
    1102 Mortar Mix 60lbs $4.00
    1125 Type N Masonry Cement 70lbs $8.00
    1125 Type S Masonry Cement 70lbs $8.50
    1136 Mason Mix – Type S Mortar 60lbs $4.50
    1136-58 Blended Mortar Mix 80lbs $5.32
    1124 Portland Cement Type I/II 94lbs $9.64
    1103 Sand/Topping Mix 60lbs $4.00
    1230 “Quikwall” Surface Bond Cement – White 50lbs $17.00
    1962 Medium Sand 50lbs $5.00
    1152 All-Purpose Sand 50lbs $2.90
    1133 Vinyl Concrete Patch 40lbs $13.43
    1585 Precision Grout 50lbs $14.00

    The task now, is to go through all of these, check the Quikrete web site to see what’s actually in each of them, and determine which product(s) are appropriate for my job. Stay tuned.

  • Pool coping project underway

    Pool coping project underway

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    Today I officially got the pool project underway, after 6 weeks or so of procrastination. After a week of foul weather, I finally got a decent day, so I took off work and rented the concrete saw. It did the job quite nicely, and quickly enough that I only needed a 4-hour rental.

    It took a bit of time to get the hang of the saw, but it was very easy to use. The blade had no problem cutting through the entire slab. The water feed did a great job of keeping the dust to a minimum, and it probably sped the job up by keeping the blade cool. I was not able to cut any of the curved areas, which I sorta expected. Not sure how I would handle these. A 7″ angle grinder might work for the area around the steps, but the corners are a little too tight for any kind of rotary blade.

    Next I need to clear the joint and clean up the mess, which figures to be more time consuming than the cutting. The wet concrete dust forms a kind of pasty mud, which sticks to the deck and won’t fully vacuum up. I’ll probably end up using my pressure washer to clean it off the deck.

    With the joint partially cleared, I can see that a lot of the fill around the pool has eroded over the years, from water seeping into the joint. I’m not planning on doing anything about it, as I’d need to demolish the deck (that’s a job for the next owner of the house). But, once I caulk the joint it’ll stop any further erosion.

    Once I’ve cleaned the joint I may go ahead and fill it (at least partially) with backer rod, to keep junk from falling into it before it’s caulked. Hopefully I’ll be able to finish prepping the joint over the long weekend; then I can focus on re-mortaring the loose coping stones.

    Oh, and the stupid Tulip Poplars have already started dropping leaves, and it’s not even July yet. It’s going to be a long summer..

  • The paradox of pool solar covers

    The paradox of pool solar covers

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    We have a solar cover for our pool. It’s essentially a big, plastic sheet of bubble-wrap that sits on the pool surface. To remove it, we crank it onto a big reel — it’s pretty much a necessity to have a reel for these things, particularly with a large pool like ours.

    After 5 seasons of dealing with solar covers, I’ve learned quite a bit about them. Contrary to what one might initially think, they don’t increase heating during the day when the pool is exposed to sun. In fact, they actually reduce daytime heating by blocking sunlight. There’s a bit of a greenhouse effect that heats the top foot or so of water, but the rest of the water sees less sun so doesn’t heat up as much. One desirable side effect of this is that it reduces chlorine usage during the day. So.. if you’re going on vacation and want to cut down on chlorine demand, put the cover on.

    The biggest benefit of a solar cover is that it reduces heat loss and evaporation at night. So for the warmest water, you want to cover the pool in the evening and uncover it during the day.

    [More:]

    The drawbacks of solar covers are subtle and a bit paradoxical (hence the title of this post). The biggie: You’d think that using a solar blanket to cover a pool would keep the pool cleaner, but it doesn’t. In fact, you could argue that it actually makes the pool dirtier. It’s true that when the pool is covered, stuff will fall on the cover instead of into the water. And sure, you can even use a leaf rake to clear the larger debris off the cover before you remove the cover. But when it rains, the dirty and untreated rainwater will collect around the folds and creases of the cover, and then when you remove the cover, the dirty water (along with whatever debris is still there) all falls into the pool and fouls the clean water. Then, because most of the debris is already waterlogged, it immediately sinks down to the bottom of the pool. Contrast this to when the pool is uncovered: the skimmers collect all the debris before it sinks, and the rainwater immediately mixes with the treated water rather than puddling up on the cover.

    Solar covers (like any cover) also encourage neglect of the pool. When the pool is covered, I find myself more likely to skip chores like adding chemicals, brushing, emptying skimmer baskets, running the automatic cleaner, etc. When you combine this with rain and extra organic debris, it can lead to an algae bloom pretty quickly.

    Conclusions: Unlike conventional covers, these things really are not meant to keep stuff out of the pool. Use them only for their thermal properties (chilly nights etc), and keep them off during the day and in particular, when it rains. If you must use the cover when it’s raining to conserve heat, uncover the pool as soon as possible after the rain stops.

    I’ve often thought about getting a leaf net cover to keep out debris. I think it would complement the solar cover nicely, and in certain instances the two could be used at the same time. I hesitate because I’m not sure how much trouble it would be to put on and take off, and how I would anchor it down to keep it from blowing away, falling in the pool, etc. When you think about it, another tradeoff with covers in general is that they are an impediment to getting in the pool. It’s much easier to go swimming when the pool is uncovered and ready to go. No one wants to spend time fumbling with a big, unwieldy cover beforehand. Still, in the late summer and early fall, when we’re swimming less frequently anyhow, the leaf net may be worth the hassle.

  • Pool coping project — getting started

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    Time to get started on the pool repair project.. better late than never I suppose. I’ve blocked off this coming Thursday to rent a concrete saw and cut back the expansion joint. Also, I’ve been thinking a lot more about what to use to mortar the coping stones in place. Terry Tamminen’s excellent book, The Ultimate Pool Maintenance Manual, includes instructions for making what he calls “patch mix”, using white portland cement and sand. He uses this same stuff (possibly with different ingredient ratios; I don’t have the book here to confirm) for patching plaster, anchoring coping stones, and grouting stones and tile. I think this might be the way to go, rather than buying premixed bags of mortar as I was originally planning. Just need to find a supplier. I’m not too confident that the big boxes will stock white portland. If not, I’ll try my favorite lumber yard. Will work on researching this over the next few days. (Update 6/22.. no sign of white portland at Home Depot).

    Oh, and the loose strip of waterline tile in the deep end fell off all by itself two days ago. I had to dive in to fish it out. Remarkably, it stayed completely intact, leaving me with a roughly 2-foot strip of mortar and pool tile, and the beam behind it is fairly clean too. I need to decide if I want to try to re-attach it, or just start over and retile (I have plenty of extra tile, so either is an option). This is the last step of the project, and won’t be happening until fall when I can lower the water level, so I’ve got plenty of time to think about it.

    [More:]

    6/21: Informative posting on poolforum.com about setting pool tile.

    6/22: Well, I decided to scrap my plans for the day due to unfavorable weather. However, I did go to Home Depot to take a better look at the concrete saw. I found out:

    • They supply all the fuel mixture I need (it’s a 2-cycle engine as I suspected)
    • There is roughly 5-6 inches from the blade to the outer edge of the dolly wheel on one side. This should be sufficient clearance to run the dolly along the pool coping edge. It will be helpful if the wheel height can be adjusted independently on either side to accommodate uneven surfaces.. but, I didn’t think to ask.
    • The saw includes a water feed, which is great because it should really help cut down on dust.
    • I don’t think it’ll fit in my car, so I’ll need to borrow my parents’ pickup.

    Now, I just need to wait for the weather to cooperate, so I can get this done. Based on the 5-day forecast, I might be waiting awhile..

    6/28: The crappy weather is finally moving out of the area, so the job is back on the calendar for Friday. Fingers crossed.

  • Finally got in the pool

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    Better late than never, we took our first swim of the season today. It’s nice to finally be using the pool, because it makes the hassle of maintaining it seem more worthwhile. It’s not quite worth all the effort and expense IMHO, but still, it is nice to be able to hop in the pool on a hot day. And when it’s not full of leaves and other assorted crap, it’s nice to look at too.

    I got a pleasant surprise when I uncovered the pool this morning.. the algae clinging to the diagonal hopper walls was almost totally gone. So, it appears that repeated brushing and superchlorination is the ticket to getting rid of this stuff. Apparently I don’t need a steel-bristled brush after all (although it may hasten the process, so I may pick one up anyhow). In future years, I’ll try to be a little more faithful with the off-season chlorination so the algae won’t take hold like it did this year.

    Also, I made a test cut in the pool deck with my new diamond blade. And I must say, it cuts very easily — much more easily than I expected. As I suspected, the circular saw doesn’t cut quite deep enough. However, I can now go ahead and rent a larger concrete saw with the confidence that it’ll do the job. The current plan is to take a day off this week (work schedule permitting) and do it. Still not quite sure how I’ll do the curved sections. I’ll figure something out I hope.

  • Pool’s open… don’t everybody jump in at once

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    Yesterday we finally uncovered the big concrete hole in the backyard. The water looks pretty good, but due to my neglect over the spring, I’ve got a bigger problem with surface-clinging algae than in past years. There was the usual green stuff on the bottom which easily vacuumed out, but the steps and the diagonal hopper walls have this better-established stuff that doesn’t want to come off. However, the stuff on the steps cleared right up when I flooded it with 12.5% hypochlorite from my siphon hose, so I superchlorinated yesterday evening. This morning I noticed that the areas I had brushed yesterday were clearing up, so I went ahead and brushed the entire pool (clouding it up beautifully, of course). Cl was 8.8ppm. Tonight I’ll add more, until all the muck is gone.

    [More:]

    Still haven’t started the coping repair project. Today (Friday) I picked up a 7″ dry-cut diamond blade for a cool $50, and I’m going to see how it does at cutting the concrete decking. It’s not big enough to cut through the entire slab, but the hope is I can make a cut around 2″ deep and then knock the rest of the piece off with a cold chisel. If it works well, I’ll go ahead and rent a larger saw to do the complete job. Whether it works or not, I’ll still end up with a nice diamond blade I can use for future projects.

    The fun never ends..

    6/12: The crap clinging to the diagonal hopper walls is proving to be very tenacious. It will not brush off easily in spite of repeated superchlorination. I can’t seem to get enough force on my brush to attack it effectively. I think I’m going to need a stainless steel brush for this. Before I try that, though, I’m going to try flooding the area with chlorine. It worked with the steps, so hopefully it’ll work with the hopper walls. Only problem is, I could reach the steps easily with my siphon tube, but not so with the hopper walls. So, I’m going to try a slightly different approach. I went to Home Depot and bought 20′ of food-grade tubing (1/2″ O.D.). I’ll use wire ties to attach 4′ or 5′ of hose to the bottom of my telepole, then put the pole in the water and start a siphon. I should then be able to siphon chlorine from my jug and direct the flow wherever I want. I will probably want to do this with the pool pump off, and somehow attach the tubing to the chlorine jug so I don’t inadvertently pull it out. We’ll see how it works.

    6/14: Tried the above last night. It works, but it’s a little cumbersome. Attaching the siphon tube to the chlorine jug is an absolute must. I used an Irwin Quick-Grip clamp. Still, I lost my siphon and had to re-prime several times. It would also be handy to have some way to easily interrupt the flow while I move the hose to different spots. I suppose it would work to pinch the hose, or I could use a spring-loaded clamp. Still, this whole thing seems like too much hassle compared to using a steel-bristled brush, assuming the brush will work. I’ll try to get to a pool store and pick up a brush in the next couple of days.

  • Next year’s pool project

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    I’m already thinking about next year’s pool project, and I haven’t even started this year’s yet…

    For next year, I’m considering adding an automatic chlorine feed using a chemical metering pump, similar to the setup described here. The main goals of the project would be:

    • Save work;
    • Save money on chlorine by matching the supply more closely with the demand;
    • Provide a continuous feed of sanitizer, thereby eliminating the need for cyanuric acid in the pool.

    If I go ahead with this, I’ll probably also move the pool’s electrical controls indoors, which I’ve always wanted to do for convenience more than anything else. I’d also need to run a dedicated 110VAC circuit to power the metering pump, so while I’m at it, I’ll install a convenience outlet near the pool equipment. Right now, I only have 220VAC there.

    The metering pump can be had from Grainger for around $300, but I’m watching eBay to see if I can get a new one cheaper.

    I’ll add random notes to this entry as I think about this one.

  • Pool still covered

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    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.