Common Spring Time Swimming Pool Start-up Problems

Problem #1: My stabilizer is gone!

This is a very common problem, usually caused by biodegradation* of the CYA (stabilizer). In other words, the bacteria in the slime in your pool ATE the CYA! (Really!) This is not good, because not only is your CYA gone, but the bacteria, after eating the stabilizer, will 'poop' ammonia and other nitrogen compounds. These will initially cause your chlorine to be consumed rapidly, and later will leave your pool much more susceptible to algae.

If you had high stabilizer last fall, and now have none, consider draining and refilling. (Of course, you must make sure you do so safely -- draining can be tricky and can even destroy your pool! As a rule, non-professionals cannot safely drain inground liner pools.)

If you don't drain, plan to consume a LOT of chlorine, getting rid of the ammonia and urea. Figure out a 10 ppm dose of bleach -- do NOT use other forms of chlorine yet -- and add it nightly. Retest the following morning. Keep dosing till you are able to sustain a 10 ppm level from PM to AM. (You'll lose it during the day, due to sun, but this is normal and even desirable.)

One very important caution: use borax to raise your pH to 7.5 or higher BEFORE you start adding chlorine. The process will go much more nicely if you do so. Also, be sure to circulate the pool water, even if you bypass the filter using the "recirculate" position on many filter valves.

If you had high CYA levels (> 70 ppm) last fall, you may consume as much as 200 ppm of chlorine in the clean up process. (~ 80 gallons of household bleach, for a 20,000 gallon pool!) Rinse the bottle with pool water as you empty them, and then plan to make a run to your plastic recycling center when you finish.

* Even though the science of this process is well established, hardly anyone in the pool industry is aware of it. I first found out back in the 90's by reading some chemical analysis papers on simazine, a herbicide once used in pools as an algaecide. I encountered for the first time that I recall in servicing a pool near Chattanooga, in the neighborhood where Congressman Zach Wamp lived. Because it was a large pool, I had to pour literally hundreds of gallons of 15% industrial bleach in, to clean up all the ammonia.

All of the work on this process has been done by people studying the biodegradation of certain pesticides. Cyanuric acid is an intermediate in these processes. But, most pool people -- even industry chemists -- don't read scientific papers on pesticide biodegradation. In fact, to the best of my knowledge, this information, as it applies to pool operation, was only published here, until Chem_Geek (Richard F.) began working with it. So don't expect to be able to confirm this with your dealer. If you don't believe me, you'll just have to do the best you can, unless you are willing to dig in for yourself. If you are, here's a paper from the EPA on the topic:

Also, as with so many of the ideas I developed, Chem_Geek has expanded them, and laid out the technical chemical analysis that explained my observations, and offered a detailed chemical explanation of the processes involved. He's pushed very hard to have some of these ideas accepted by pool code authorities and others. Who knows? Maybe in 10 more years -- by 2021, they will be!

Problem #2: I've added chlorine, and added chlorine, and I STILL have no chlorine when I test the pool water!

Read #1 above, carefully. (You can skip the part in italics, if you like!).

Consider if it could apply to you. If so, test your stabilizer -- CYA, cyanuric acid -- level. If your CYA level NOW is 0 or close to it, but it was 40 ppm or more last fall . . . odds are your problem is the remnants of biodegraded stabilizer.

There are two options:

  1. You can drain and refill (maybe -- not safe for all pools!)
  2. You can chlorinate till the ammonia, etc. is gone.

Those are probably not the choices you'd prefer. But, I'm not aware of any other good options. Using alternative shocks, especially oxy-shocks, will not work and will cost a great deal more money.

There are some things to watch out for.

  1. Your swimming pool water is NOT stabilized, so high chlorine levels will be MUCH more likely to bleach things out. This is mostly an issue for vinyl liner pools, but some paints can be bleached, as well.
  2. Your pool is NOT stabilized, so if you chlorinate in the morning of a sunny day, you will end up losing much of your chlorine uselessly to sunlight.
  3. It will be hard to predict your chlorine level after each new dose. Do NOT test with DPD tablets. You are likely to reach a point which will bleach those tablets out. You could end up continuing to chlorinate, after you no longer need to do so. You may use a DPD-FAS drop count test, but I'd recommend using OTO or SYD (strips). Once you are able to hold a chlorine level, you may switch to DPD for better accuracy.
  4. Initially, your stabilizer-eating bacteria and biofilms will STILL be active in your pool. So, do NOT use stabilized chlorine to start with -- you could end up making your problem worse, faster than you make it better. This means NO dichlor powder. Use bleach or calcium hypochlorite only.
  5. If you use cal-hypo (calcium hypochlorite) be VERY careful to pre-dissolve it. You don't want to bleach your liner or paint by dumping piles of cal-hypo on the bottom.
  6. You WILL need to circulate and filter continuously during this process. If you use bleach, it would be possible to clean up the ammonia without circulating, but you'd STILL be better off to run your filter 24/7.
  7. Various noxious chlorinated nitrogen compounds (chloramines) will form during the ammonia removal process. They will (hopefully) leave your pool as gases. DO NOT COVER YOUR POOL DURING THIS PROCESS!
  8. Often, I've told people that, contrary to many over-cautious C-Y-A (not CYA) statements, they could go ahead and swim. This is not one of those times. Do NOT swim till your pool is cleaned up! The chloramines, mentioned above, are NOT swimmer friendly.
  9. As mentioned above, use borax to get your pH up above 7.5 BEFORE you start. You can't avoid creating chloramines. But the ones that form at 7.5+ are likely to be less obnoxious and stinky, than the ones that form below 7.0. In particular, NCl3 (nitrogen trichloride, trichloramine) tends to form at lower pH levels, and it's all kinds of nasty. (You DID remove your pool cover, didn't you?)
  10. Do NOT start adding stabilizer, or using stabilized chlorine, until the pool is clear, slime-free, and can hold a 2+ ppm chlorine residual overnight.
  11. Do NOT run your salt chlorinator, your heater, or any other pool equipment, except your pump and filter, while you are cleaning up.


Problem #3: I've added chlorine, and added chlorine, and I STILL have no chlorine when I test the pool water! But, I've tested and I do have stabilizer and it's pretty much at the same level it was last fall!

Ok, so what did you put in your pool?

Seriously, when folks can't keep chlorine in their pool there are XX main reasons:

  1. The pool is clear and there's no stabilizer. You can see if this is the problem, simply by dosing in the evening. If you add chlorine in the evening, test an hour before dark and then an hour after sunrise . . . you'll still have chlorine if the problem is stabilizer.
  2. The pool is clear, there IS stabilizer, chlorine holds overnight, but disappears during the day. In this case, the question is, "Have you used any sort of bromine or sodium bromide?" (Bromine tabs, anything from United Chemical, or ANY OTHER white granular 'chlorine booster'). If so, you need to see this page, about bromine's effect on chlorinated pools.
  3. There's ammonia (or other nitrogen junk) in the pool  from Yellow OUT or Mustard Master. Sometimes pool owners have used products containing ammonium chloride or ammonium sulfate, like Yellow OUT or Mustard Master. These products create a situation like that described in #2 above, only not as severe. The solution is the same, however.
  4. Someone attempted to clean up the pool with massive doses of foamy algicides. Again, this creates a situation sort of like #2. In one sense, it's less severe, but the algaecides react with chlorine slowly, so it can take a long time to get the pool back to normal. Again, high pH and high chlorine and time is the solution.
  5. There are probably other reasons for this problem that I can't think of now, but I'll add them as they come up. Meanwhile, you can ask on the Pool Forum

Problem #4: My pH and/or my alkalinity and/or my calcium is too low.


Do NOT panic, and do NOT let a Biolab dealer bully you into overdosing with alkalinity and calcium increaser! Every spring, pool owner's post panicked pleas* for help, following the dumping of dealer recommended chemicals into their pool.

The result of this overdose is always the same: their pool turns to milk, when the baking soda (alkalinity increaser, Balance Pak 100) combines with the calcium chloride (hardness increaser, Balance Pak 300) to precipitate suspended calcium carbonate (lime dust!). If the dealer has also given them soda ash (pH increaser, Balance Pak 200), the problem will be correspondingly worse.

Unfortunately, by the time they post here, it's already too late for things to be easy: cleaning up a milked-up pool is a pain!

So, this spring, if your pH is low, raise it to 7.0 - 7.2** with BORAX, not Balance Pak 200 or soda ash, and then proceed with your pool clean up and chlorination. Do NOT worry about your alkalinity and calcium levels yet. Once your pool is up and running and clean . . . THEN you can GRADUALLY raise your alkalinity levels. After that's done, if you need calcium (vinyl and fiberglass pools usually don't!), you can GRADUALLY raise it.

Doing it my way, instead of the Biolab way, will save you a LOT of time, money and trouble!

*My boys complain that I allow my affinity for alliterative allocution to become truly annoying!

** As noted above, if you are cleaning up the chemical 'poop' left when bacteria ate your stabilizer . . . then your pH needs to be somewhat higher.


Problem #5: Oh no! What do I do about the dead animals in the pool?

It's gross, and if they were pets or cute, it may be very sad . . . but it's not really a serious pool problem.

Just scoop or lift them out, and dispose of the bodies, and proceed with the cleanup. If the pool is otherwise ready to swim in, raise the chlorine level to 5 - 10 ppm, and wait 24 - 48 hours before swimming. But, if you still have to clean up the pool, the normal chlorination, shocking, and filtration will take care of any bacteria danger.

But, do make sure to remove any piles of leaves or debris from the pool at least 24 hours before swimming. It's rare, but such collections of debris can create a 'safe haven' for dangerous bacteria or organisms. So, clean it up, then chlorinate, then wait a day before swimming.

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