A complete water change here (~20,000 gallons) would run about $73 (including all the taxes and "fees" that get added to our water bills).
...Jim Thompson
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| James E.Thompson, P.E. | mens |
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Leftist weenie Bush-bashing bed wetters, scourge of the earth
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Last time this happened I just filtered the dickens out of it. Took two DE-recharges to do it but that certainly was cheaper than all this chemical stuff. And probably easier on the environment.
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Chlorophyll d's absorption peak is at 699.5 nm to 740 nm, depending on the source of information (probably varies with various conditions), and chlorophylls do not absorb much of wavelengths more than about 300 nm longer than the long wavelength peak. So wavelengths longer than 770 nm (very near infrared, actually slightly visible) are largely not utilized.
A similar product available here is the carbonate, but it's not pure La, but a mix of lanthanides. All that really matters in a pool is that it's soluble and precipitates the phosphate.
It's even illegal to *top up* a pool here now, and has been for two years. However, Jim is *partly* on the right idea here. More below.
Partial shade *does* promote algae growth, regardless of wavelength. It's always the hazy bright days that big breakouts occur. Nutrient content (phosphate etc) also matters.
You can prevent algae outbreaks with a high enough chlorine content. Well, duuur... but the recommended Cl level may not be enough...
The one thing that isn't widely known is that a high TDS (total dissolved solids) can bind up your chlorine so it's much slower acting. This effect has been wrongly blamed on cyanurates from using isocynanuric acid to chlorinate, but that's a relatively small contributor to TDS - since cyanuric levels are supposed to be kept below 100PPM, and you don't run into trouble until you hit a TDS of
3000 PPM or more. The chlorine levels may appear normal, and the total alkalinity also, yet you can have a buildup of ionic content that's not active in determining pH, so doesn't show up in TA tests.
I got into this problem a couple of years ago before our drought was so bad, and fixed it after trying everything else with a partial refill. The problem was worsened because I wasn't backwashing our sand filter very often, so wasn't needing to top up the pool very much. I had been using isocyanuric chlorine, and was told I had "cyanuric lock", so I tried to acquire some melamine to precipitate it, so as to avoid doing the recommended water change. How I would have filtered out the ultra-fine precipitate was going to be the next problem.... anyhow I got onto one of Australia's top water scientists and he told me that cyanuric lock was a myth, and the problem was TDS. In both cases the prescribed cure is a water change, one that melamine wouldn't have prevented.
The bottom line is that a (partial?) water change may be your only option. These days, I have almost half of our roof plumbed directly into the pool, and catch enough that I can backwash fairly freely. When rain has been scarce, I backwash into a large drum, let that sit for 2 days, then run 95% of the water back into the pool before chucking the residue on the garden. Our pool has been pristine since I enacted that plan.
I hope this helps. At least, it's something you can prepare for winter, assuming you will have more rain then. In the meantime, you might have to use astronomical amounts of Cl (up to twice the shock-treatment amount) to get it under control, and starve it using the lanthanides until it rains. Using the filter alone won't help, as it only removes the algae, not the spores that will spark the next outbreak - they're too small even for a DE filter.
It never rains in the summer months here. Such a ban would be impossible and California voters can become rather brutal if anyone would try to pull that off. He'd never stand a chance, he would have torched his career for good.
Yep, lotsa chlorine. Next gallon goes in tonight after the backwash.
We had lots of solids floating on the surface lately, on account of the fires.
So far filtering and higher chlorine always got it back. Last time we used a pool cover to keep it warm. Big mistake. Got too warm, then green. Took two day and two DE reloads and it was pristine again. Then
842 wildfires started around us a few weeks ago ...
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If your pool reaches green the algae often infects the plaster... you may need an acid wash.
...Jim Thompson
-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at
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| 1962 | It's what you learn, after you know it all, that counts.
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I just spent today adding rock to a water fall we have on the property to control erosion, laying out poles, wire, and drops for plants in our garden, doing some more site prep for a house I'm building in the back for my son, and adding more space for the chickens. Busy, as well, today. Sounds like you are all set up for wavelength and intensity calibrations, though. ;)
If you are doing a professional unit like that, you must have the calibrated tungsten lamps at hand with the right distances set up as well as the merc-argon vapor lamps (assuming near visual spectrums involved.) Should be a snap to set up a home brew. I think Edmund Scientific used to have a nice diffraction grating available for $1 each. Might still have them. Ah.... Nope. Just looked and don't see them. I do see a $7.95 holographic one, though -- 12,700 grooves per inch. A DVD is about 34,000 per inch (0.74 micron, I believe.) I'll stick with my DVD-RW, for now. (The DVD-R's that I've tried have a nasty absorption in the red that splits that area up in half. So I don't use them.)
Since you're using DE you don't have the same backwash needs anyhow, but a proper backwash of a sand filter takes up to 1000 litres, which is an inch of depth in our pool. Folk doing that every few weeks are unlikely to run into TDS problems. We had problems because I limited the backwashing to a small fraction of that.
You won't need so much if you can get the TDS down. Get your water tested for TDS - it's a simple conductivity test - and try to get it down under 2000 ppm.
Triple whammy - obscured sunlight, nutrients and TDS. You can fix the latter two... lanthanides for the 2nd.
It will get it back, but the pool can be still full of invisible live spores ready to explode again. A massive superchlorination on a pool with low TDS can kill them and help you get over short-term events without a breakout.
Well, so far: Backwash yesterday night. Had a nice Fat Tire Ale with that. First some dark green came out, then yellow, then lots of gray. That must be ash because we normally never see that. Let the pump run overnight, pool is now almost clean again. Chlorinated it well past the upper indicator limit. Pump will keep running until a client is done with their EMC session in a couple hours from now. I don't want to run it any longer because we have a flex alert in Nor-Cal, meaning not enough electricity to go around.
The big surprise: pH was smack dab in the middle of the ideal range. That usually never happens, our pool tends to slowly drift up and needs the occasional squirt of muriatic acid. Amazing.
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Okay. An interesting thing to me is that young students can set up a viable system to actually "do some science with" for perhaps $20. Single layer DVD-RWs are pretty cheap, cardboard is cheap, if you want to be picky and avoid just cutting a narrow slot in hard paper you can use cheap razor blades for the slit -- still cheap, and calibration lamps for wavelength cost almost nothing, as well (I spent $8.) A cheap megapixel camera can be had for $10, as well, to take photos of the image.
A problem is calibrating for intensity, which requires a calibrated source (a $10 or $20 tungsten lamp with $1000 of value-added calibration against a maintained standard, plus a 1000ppm or better accurate current control unit which adds similar costs) and some precision setup (not expensive, but care is required regarding the optical situation involved, aperatures and so on, as well as the lamp standard an d power supply.) That's the problem part.
But if the curiousity is more about one situation relative to another, a lot of interesting science examination can be done on the cheap, without the intensity calibration part of it. Fluorescence and phosphorescence bands, too, for example. LED bandwidths, etc.
Also, a standard (uncalibrated) bulb can be placed within a shoe box as part of a system for cases where a light source is important, looking at absorption bands.
I don't cut or otherwise modify the DVD-RW itself, though. Stressing it is "not good." I use a small cut-out baffle, though, made of black card stock that I also sometimes cover with black flocking. I include several cutaway slot positions for inserting a disk, so that I can use either the CD-ROM (different lines per inch require different angles) or the DVD-RW and just drop one into the box behind the baffle.
Spectrometer? Just one of those telescope and collimator around-a- circle things? Or with the gratings and/or prisms (who uses prisms anymore -- like my nice, old Beckman)?
Well, 'totally different' sounds interesting. I've worked modestly on optical designs, regular stuff like eyepiece and catadioptric telescope design, as well as Fraunhofer diffraction and interference systems with vector propagation (not scalar) of light for laser CD/DVD reading through astigmatics and quad detectors, spatial filtering, etc., so let me know when you can. I'm always curious to learn more. If there is a patent disclosure, that too, when allowed to say. I'd appreciate it, if you are open to considering it.
One interesting technique is FTMS, Fourier Transform Mass Spec. This is cool: you ionize some molecules in mostly vacuum, and dump them into a circular cavity inside a biggish superconductive magnet. An antenna applies a power RF chirp, which spins up their cyclotron resonance orbits; then you listen, digitize for a second maybe, and FFT the spin-down signal, in the low MHz range. The result measures the mass of each molecule to around 1 PPM precision, enough to usually define the atomic/isotopic composition unambiguously. Even more fun is to feed one of these beasts from the output of a liquid chromatography column or a quadrupole preselector. Your tax dollars at work fer sure.
The machines are full of RF amps, turbopumps, digitizers, processors, RF quadrupole preselectors, ionizers, LC columns, high voltage supplies, all sorts of EMI-nasty stuff.
When it hits the market they might allow it. That's one of the dilemmas consultants face. Unlike most employees they cannot talk about recent projects with a prospective client. Heck, some of my agreements even prohibit me from talking about the mere existence of the agreement to anyone other than law enforcement and such.
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