Time to replace sand?

[TheGoose]

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.

[jonno]

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

[aylad]

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

[Watermom]

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.