Time to replace sand?

Hi everyone - my first post, please help.

Short story: Started putting in algeacide, but water stayed green. Put in 1 gallon over 3 weeks (I didn't know that it is a preventative and that only chlorine kills algea - now I know).
Spent 3 weeks, shocking, brushing, putting a little Fiber Clear down skimmer, but pool stayed very cloudy (visibility less than 20") and green.

I bought the Taylor water test kit through the link from this forum. This mornings numbers are:
Free Chl: 3.2
Avail Chl: 2.2
pH: 7.2 (then I added 6 lbs soda ash per the chart)
Ttl Alk: 180
CYA: over 100
Calcium Hardness: 160
Other measurements from pool store last Thursday:
TDS: 1500
Phosphates: 0

Last Thursday (my 5th trip to the pool store), they told me to do the "Green to Clean" treatment. Backwash, Boost pH to 8.0 (added 8 lbs of soda ash to do this), wait 4 hrs, brush sides and bottom, add "Green to Clean" and 4 lbs shock, wait 12 hrs add 4 lbs shock (repeat shock two more times, waiting 12 hrs each time).

It finally turned my water from green to blue, but water is milky/cloudy. My hand disappears as soon as the water is past my elbow.

Pool is 26,000 gallons, vinyl liner, sand filter (275 lbs sand). Water is about 10 years old, sand is about 6 years old. The pressure does not vary much before/after backwash.

I will change the sand this weekend. But I want to run this by the experts - Is there anything else I should do? Is the water safe to swim in now?

Many thanks! John

Quote:

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Originally Posted by jonno

I will change the sand this weekend. But I want to run this by the experts - Is there anything else I should do? Is the water safe to swim in now?

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Stay out of that pool store! You've been what we call around here "pool-stored."

Your CYA is 100 which is very high. The bad news is that test kits cannot differentiate past 100 so in all reality, it could actually be a lot higher than 100. You have a couple of options:

1. Do a partial drain and refill and try and lower that CYA level. Do NOT totally drain your pool however. You should be able to safely drain 2/3 of the water, though.

OR

2. Run higher than normal chlorine levels to compensate for the high CYA. Take a look at the Best Guess Chart link in my signature below for needed levels.

A couple of other things you'll need to do if you decide NOT to do a partial drain and refill:

Your alk is high at 180. After your pool clears, you'll want to try and lower that some. Don't use anymore soda ash to raise pH because it is raising alk at the same time. Instead, use 20 Mule Team Borax (laundry aisle at Walmart) to raise pH.

Also, I'd suggest shocking the pool up to 25 and try and hold it at that level until you can go from sundown one evening til sunup the next morning without losing more than 1ppm of chlorine. At that point, you can let the cl drift down and keep it between 8-15 ALL the time or risk an algae bloom. You should also be running your pump 24/7 while you are trying to clear this up.

Also, please get a good test kit. Click on the Amazon link in my sig and get a Taylor K-2006 or 2006C which is the same kit with a larger quantity of some of the most used reagents. Buying through that link makes the Pool Forum a little money on the sale which helps keep us online. Only buy if the seller is Amato Industries. Some other sellers are substituting the K-2005 which you do NOT want. You'll need the good kit regardless of whether or not you drain and refill or not. But, if you do NOT drain and refill, you MUST buy it or else you won't be able to measure the high cl levels you'll be required to run.

Hope this helps. Let us know your preference between option 1 and 2 and we'll help you go from there.

EDIT -- Almost forgot. You do NOT need to change your sand. My sand is 11 years old and many other people have sand much older. Don't bother changing it.

EDIT again -- to add a link about lowering alk. Don't worry about this yet if you decide to do that partial drain/refill.

http://www.poolsolutions.com/gd/lowe...p-by-step.html

EDIT yet again! Because I forgot to welcome you to the forum and also to say thank you for becoming a subscriber. Subscriptions help us be able to stay online!

I have been fighting the same problem off and on for years. What I discovered is that I had lost a little sand over a few years and the filter was not working correctly. When changing the sand last week I noticed that there was more than I had removed. Pool water is much better now.

I'm gonna rig up some unions ( I used regular couplings last time) so that I can pop the top off the filter and add a bag or two of sand per year. Either that or switch back to a DE filter.

Thanks watermom and thegoose. Can you tell me if the water is safe to swim in? (Family really wants to swim!) I used the Taylor K-2006 kit to get the numbers reported above.

I expect the CYA is off the charts because that black dot disappeared way before water reached the 100 level in the small tube.Before doing the "Green to Clean" treatment last week, the CYA level was 30 and the Ttl Alk was 90. Since it was very cloudy before the sky-high CYA and Total Alk, the "Green to Clean" treatment killed off the algae but caused these high CYA/Ttl levels. I'll recheck the water tonight to make sure I did it correctly.

I'll shock the pool to 25 ppm - what kind of shock should I use to do that and how can I figure out how much to use. I'll also keep the chlorine high for now and see if I can rig up a aeration. I'll also check the sand level and make sure the pipes in the filter are in good shape.

By the way, draining and refilling 2/3 of the pool, will cost $800 just for the water. The vinyl liner is already 13 years old and getting harder to keep the beads seated in the coping. Pretty soon I expect that I'll have to replace the liner so, it would make sense to replace the liner and replace the water at the same time -- but I can't afford to do that (both kids in college).

Any other advice is most welcome! Thanks again - John

For a CYA over 100, you need to be keeping your chlorine levels between 8 and 15 ppm at all times to keep the algae away, so you need to get some chlorine in the pool ASAP or you're going to undo all the work you've done. In a 26K gallon pool, each gallon of 6% bleach that you add will raise your chlorine by just over 2 ppm, but not quite 2.5, so you can use that as a guide. Since your CYA is already high, I absolutely would not advise you to use dichlor powder or trichlor pucks in this pool, as the CYA will just keep climbing through the roof. I would use plain, generic, unscented, household bleach. Check the label, make sure it's 5.25 or 6% in strength.

Generally we recommend maintaining the shock level until you're not losing any chlorine when testing at night and again in the morning before the sun hits the pool (to rule out any chlorine loss due to sunlight). There is no danger to you or your family from the algae, per se, but if there is algae growing in the pool, then that means there's not enough sanitizer present to kill off any other viruses or bacteria that may be in the water. Also, with a cloudy/milky pool, there is a very real danger to anybody that gets into the deep end and is having trouble but cannot be seen by others around the pool. I would wait to swim until you can at least make out the bottom, and until you're not losing any chlorine overnight. At that time you can let your chlorine levels drop to normal, but never less than 8 ppm as long as your stabilizer is that high.

Aeration can be done via fountain, splashing kids, or just by pointing your returns upwards so that they cause a ripple in the water.

Janet

Is the pool still green or only cloudy now? What is the ingredient in "Green to Clean?" I can't imagine that it could cause your CYA to go up from 30 to maybe 100+. Maybe the test result was read incorrectly the first time. Also, retest your chlorine and get a FC and a CC reading for us.

In your pool, each gallon (4 quarts) of 6% bleach will add 2.3ppm of chlorine to the water. Use that to help you determine how much bleach to add each time you test to take the cl back up to 25ppm. Have you done the overnight test? That is where you test the chlorine in the evening after the sun is off the pool and then again within two hours of sunrise to see if you are losing more than 1ppm of chlorine. If you do, then you are still fighting something in the water and need to continue shocking.

I know your family is anxious to swim, but we need to be sure things are safe before recommending that you let them in the pool.

I understand about not wanting to drain. Just run higher than normal chlorine levels after you get this cleared up and you'll be ok with the high CYA. Don't add anything else to the pool right now except for bleach to get to 25. (Except for some Borax if your pH drops any below 7.2.) Test as many times a day as you can and each time get the cl back up to 25. There is no such thing as testing and dosing too often when you are trying to clear a pool. The more times a day that you do so, the faster it will clear up. Run the pump 24/7.

EDIT --Apparently Janet posted while I was typing, but our advice is basically the same.

The pool is no longer green - it is only cloudy now.

Here is the pool when it was green: http://www.flickr.com/photos/3521519...in/photostream
Here it is last Saturday when it finally turned blue: http://www.flickr.com/photos/3521519...n/photostream/
Here is a close-up to show the unchanged poor visibility: http://www.flickr.com/photos/3521519...n/photostream/

When I get home tonight, I'll check everything and report back. I'll also pick up a bunch of 6% unscented bleach and borax and add it to bring up the chlorine to 25 and do the overnight test.

I don't know what is in "Green to Clean." Here is the link to the product page, but, mysteriously, they do not disclose the active ingredient. http://www.green-to-clean.com/FAQ.html

Found the ingredients to Green to Clean - it is "Disodiumsalt of ethylenediaminetetraaceticaciddihydratediammoniums ulfate
100% (active ingredient)" Here is the link to the MSDS.

I know nothing about Green to Clean. Post current readings and tell us of any changes in the water quality.

Here are this evening's numbers:
FC 0.5
CC 1.0
pH 7.2
TA 190
CH 130
CYA over 100

I opened the filter, stirred up the sand and backwash out lots of gunk.
Then added 60 lbs of sand to bring it up to the right level.

I pointed the return upward and now have a small standing wave rippling the surface.

I added almost 11 gallons of 6% bleach (7.5 jugs each with 1.42 gallons) and tested the water about an hour later.
FC = 4.0
CC = 6.5

Using the formula of 1 gal. increases chlorine by 2.3 ppm, this amount of bleach should have brought the chlorine up to 25. I added the remaining 6 gallons of bleach (4.5 jugs) and will test in the morning. If the 1 gal = 2.3 ppm applies, then this will only bring me to 21 ppm, but I'm out of bleach, it's late and time for bed. I'll test in the morning and report in.

My pH is 7.2 and it took 10 drops to bring it up to 7.4. Should I add a box of Mule Team borax now or wait until after the chlorine passes the overnight test?

Thanks!