Green oak tea

[Barry]

Our in-ground pool was not properly covered over the winter. Through the fall and winter, lots of leaves ended up in the pool. When we started springtime cleaning, the pool was green and we couldn't see the bottom even in the shallow end.

All-told, we removed at least a foot of leaves from the bottom of the pool. I think we've gotten almost all of it but I can't see the bottom so I'm sure there is some residual debris left.

I've started conditioning the pool, shocked the heck out of it, dosed some algaecide and added some clarifier. I've cleaned the filters. The color/clarity is a LITTLE better (we can see the bottom in the shallow end) but it's still a LONG way from where it ought to be.

My gut feel is that we brewed a 15,000+ gallon pot of oak tea over the winter and we may have to drain/refill to restore it to its correct state.

Thoughts?

Thanks,
Barry

[southernlady]

YOU have to get your ph and alkalinity right,then shock in once,then get your chlorine level up.THE ph, and alkalinity very important part of your pool. AND the chlorine level also is very important to keep it up. when the algae is killed then vacuum it really good., You may have to vaccuum a few times. the algaecide only keeps the algae from growing . it doesn't kill it.Then have you water checked for metals and calcium level and stabilizer . The chlorine is what keeps the algae from growing . The shock kills the algae. i went to pool school a couple of weeks ago with my sister and learned alot from that guy.I was doing everything wrong......IM gonna try liquid clorine this time.But read up on it cause he didnt tell me that so....I just read on here that people use it.

[chem geek]

See this sticky for more info on how to clear a pool using chlorine alone (an example shown here).

[Barry]

Well, I tried the techniques mentioned in the previous posts and didn't have quite the results but I did learn a few things.

Lesson #1: Test strips cannot be very accurate.

Based on initial readings of about 7.5 pH, 30 CYA, 0 FC, I worked out that about 4-5 gallons of bleach was the right amount to get a 20Kgallon pool up to a shock value of 13 FC.

Based on recommendation of 4x bleach available, I bought about 20 gallons of bleach.

I began the process with ~4 gallons of bleach, checking and supplementing every 30 minutes. After 30 minutes, my test strip still showed 0 FC. I added another 4 gallons with little FC impact the next 30 minutes. After about 3-4 cycles of ~4 gallons each, I finally saw a FC reading of about 2.

Visibly, the pool was clearing somewhat but not a lot. I sent the wife to the store for another 20 gallons and proceeded to hammer the hell out of the bleach dosing.

I never did get above a test strip reading of FC 2. I cleaned the filters once during the day and brushed the bottom/sides somewhat.

End result: I can see the bottom in 3-4 feet but not in 10 feet. The water still has a greenish hue to it but it's nowhere near as dark as it was originally. It's clearly better but it's also still clearly green.

I'm guessing my next step will be to take a water sample into a pool supply store and see if they can give me any suggestions. At this point, I'm not sure what to do next and can't see a reason why more bleach is the answer.

Any additional suggestions?

Thanks,
Barry

[jdlloyd1183]

Stop with the bleach already!!! not enough power for very little money. Get a good cal hypo shock product, preferably poolife turboshock the strongest on the market. put 6 lbs of this in, circulate over night. The whole pool should be cloudy blue gray, not even a hint of green. if there is green color or it gets greener, you have copper or some other metal present in the water. What kind of algaecide did you use?? Make sure to use a good polyquat 60 algaecide, as this is like a clarifier and algaecide in one. A FULL water test would be a good idea, and make sure they test phosphates, metals, and TDS for you, not always common practice among pool stores. Post your results so I can help you further. By the way the test strips were probably bleaching out when you tested with them because of high chlorine.(make sure to use calcium hypochlorite shock,or cal- hypo for short, of at least 70% active ingredient turboshock is 78% for example. After a 24 period with the shock, test the FC if btwn 0-2ppm, get hold of a good spray flocculant, such as Natural Chemistry's Clear and Perfect. Spray on the pool surface evenly with pump off. Leave off for 24- 48 hours. poool should be clear, with debris settled to the bottom. Vac to waste , circulate pool for 6 hours, get the water tested and adjust your balance and sanitize. Also, What kind of filter do you have??? Cartridge, sand , DE???? Very important that youtell me this

[jdlloyd1183]

meant to say not enough power for the money about bleach

[chem geek]

The key is to add enough chlorine to get measurable FC and to add it frequently as well as brushing and filtering. There is no question that bleach is not concentrated -- chlorinating liquid is better -- but Cal-Hypo is not cheaper per FC in general. The cost of chlorine sources is shown here. 73% Cal-Hypo is around $3.31 for 12 ppm FC in 10,000 gallons while bleach (at $1 for a 96-ounce jug) is around $2.63. Even bleach that isn't on sale or chlorinating liquid is comparable in price to Cal-Hypo. The bleach and chlorinating liquid are just weaker by weight, not by price, so using more to get to the same FC level has identical effect in the pool water.

In this person's case, I suspect that the Cyanuric Acid (CYA) level may have been very high (the test strips are not usually accurate) in which case it doesn't matter what kind of chlorine you use -- it will be very hard to clear the pool because the high CYA makes the chlorine less effective, regardless of source. Chlorine's power (technically, the concentration of hypochlorous acid) is proportional to the ratio of FC to CYA so if you have high CYA then it is usually best to do a partial drain/refill to lower it since that's got to be done eventually anyway. If one wants to kill the algae quickly, then a phosphate remover will do that but is expensive. A copper algaecide will also do it but can risk staining. Or perhaps the CYA was as measured, but after the algae was killed the high pH made the water green from copper that was added in an algaecide.

I didn't realize that the sticky I linked to didn't mention testing the CYA first and if too high that a partial drain/refill would be best. Instead, it assumed that the CYA wasn't too high (i.e. not above 80 ppm) and gave advice regarding the FC level for a more normal CYA level. I also didn't realize that the sticky didn't start off saying one needs an accurate drop-based test kit [EDIT] (it actually DOES say to use a good test kit in the Be Prepared section) [END-EDIT]. Sorry about that.

Since this person did not post their Calcium Hardness (CH) level, the advice of using Cal-Hypo for shocking could cause cloudiness since for every 10 ppm FC added by Cal-Hypo, it also increases CH by 7 ppm. Continued addition of chlorine, whether bleach, chlorinating liquid or Cal-Hypo is not bad, but if the CYA is really high it will continue to be a slow process. I suggest that Barry get a good test kit such as the Taylor K-2006 for a good online price here or the TF100 test kit from tftestkits(dot)com here (with the TF100 kit having 36% more volume of reagents so comparably priced "per test") so he can know his true CYA and CH and FC levels and if the CYA is above 80 ppm then do a partial drain/refill to lower it. Test strips are not very good for some of the measurements. If he wants to just clear the pool more quickly and doesn't care about cost, then a phosphate remover is the fastest way to stop the algae from growing, but chlorine will still be needed to oxidize the dead algae to clear the pool (or a clarifier or flocculant can be used to speed up the clearing at more cost).

Barry, I'm sorry I didn't read the sticky thoroughly first since the most important first step is to have your own accurate test kit (such as those mentioned above). Otherwise, you're shooting in the dark. If the CYA is too high, then chlorine isn't the best approach regardless of source since it will take too much. If the CYA were well above 80 ppm, then a partial drain/refill is better to start with since the CYA will need to get lowered anyway and that's the only way to do it. Also, when you start a process and seem to get stuck without continued progress after a few days, please check back in. Right now it's hard to know whether you've still got algae or whether the green is from copper (did you ever use a copper-based algaecide?) because copper will turn the water green when the pH rises from the chlorine. In fact, I was in a rush when you posted so just linked to the sticky, but I should have asked you whether the water was green and murky like algae or whether it was more clear green which would more likely be copper. Also, I should have asked you about the type of algaecide you said you used.

If you are going to the pool store, have them test for copper. If your water is more of a clear green rather than cloudy green, then it's more likely to be copper and chlorine is not the answer. If they find copper, then you need to lower the pool's pH (let the chlorine level drop and the pH should drop some as well) and add a metal sequestering agent. If the pool is cloudy and not clearing from filtering and maintenance of shock levels of chlorine, then the flocculant advice is appropriate and another brand that is good for that is OMNI Liquid Floc Plus, but you'll need to be able to vacuum to waste if you use a flocculant as it will just settle what it consolidates to the bottom of the pool. Otherwise, a clarifier could be used and the advice about PolyQuat 60 is correct that it is also a clarifier (as an algaecide, it's better at preventing algae than killing an existing bloom). Normally, such items are not needed, but normally one tests the pool first with a good test kit and does not use a copper-based algaecide due to its side effects.

Richard

[Barry]

Thanks for the feedback. Sorry I haven't been able to reply recently.

I've done a few things this week and can see the light at the end of the tunnel. Unfortunately, even though I'm an engineer, I can't really say I've taken a hard analytical data-driven approach nor have I documented my efforts/results.

Answers to questions:

Yes, I added some algaecide about a month ago. I'm not gonna go grab the bottle right now but I want to say it was Algae-Stop, maybe HTH brand, from Walmart.

Cartridge-based cannister filter (4 internal mechanical filter tubes)

I don't THINK I had high CYA, for reasons mentioned below.

Summary of progress in somewhat the same order:

I saw results after the bleach exercise, just not earth-shattering. The pool was clearer but still green. (I'm thinking we hit the algae but not the copper residue.)

I read additional posts about green water from copper. I added some pH minus to drop my pH (this seemed to help some too, making me think I did have a copper effect as well).

I alternated days with pump off one day to allow settling, vacuum, then run pump on one day. Any time I see the filter pressure running high, I cleaned the filters with a pressure washer. Over the week, the clarity has continued to improve.

This weekend, I shocked pool with HTH shock and picked up a drop-based test kit. If anything, the tests indicated little to no CYA, calling for stabilizer. I haven't added any yet.

Current status:

At this point, the shallow end of the pool is looking really good and I'm just now able to start to see the bottom of the pool at the deep end. I was able to vacuum the remaining leaves out so that I could run the "snake" vacuum without clogging. The filter needs cleaning again so I'll do that this afternoon. At this pace, I'm feeling pretty good about having it in good shape over the next week.

[chem geek]

If the algaecide was HTH Algae Stop, then this is a linear quat and does not contain copper (so that's good). Of course, that leaves the question of where the copper came from in your pool, if indeed your pool has copper in it (which seems possible given the improvement in color when lowering the pH). Copper tests are expensive so this is when your pool store can be helpful and test the water for metals and sell you a metal sequestrant IF significant copper is measured.

HTH Shock is is Cal-Hypo which is fine so long as not overdone (unless your Calcium Hardness is low). Just remember that for every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by 7 ppm.

If your pool indeed has no CYA in it, then that would have the chlorine break down in sunlight very quickly -- losing half the FC every half-hour in direct noontime sun. If you noticed that the FC dropped quickly during the day but not as quickly at night, then that would be a strong indicator of not having CYA in the water (though the killing of algae can still have the FC drop at night -- just not as fast). That would prevent the chlorine from sticking around at a high enough level to kill the algae and would explain why it's taking so long. Also, if you had CYA last year and it went to zero over the winter when the pool was let go, then this can happen from soil bacteria (that get into the pool) consuming the CYA and turning it into ammonia. If that happened, then it will take a LOT of chlorine (from any source) to get rid of. Hopefully, this isn't the case. You can get a very inexpensive ammonia test from an aquarium/fish shop to be sure.

If you get a good test kit for normal pool parameters (Taylor K-2006 or tftestkits(dot)com TF100) and test the numbers yourself, then if the CYA is truly near zero, then you can add some to the pool and that will help the chlorine stick around longer to kill the algae faster. CYA is slow to dissolve. One alternative, since you need to add chlorine anyway, is to get some Dichlor as it is faster dissolving and will add both chlorine and CYA to the water. For every 10 ppm FC added by Dichlor, it will also add 9 ppm to CYA.

I'm really, really sorry I didn't respond to your post more directly instead of just linking because getting a good test kit is critical to knowing what to do, mostly because the CYA level is so important. Without any CYA, the chlorine gets broken down from sunlight. With too much CYA, the chlorine is not effective. So it's really important to know the CYA level.

I'm glad you feel you are on your way and again am sorry I wasn't more helpful initially.

Richard