Replacing water to get rid of CYA

I just discovered the whole CYA issue. I know I need to replace water to get rid of CYA (it's 150). I was surprised to learn that although I have a pool pump, there's no way to use it to drain water. I need to rent a pump at the cost of about $50/day. I was also told to drain only about half of the water at any time in case there's water below the pool that could cause the empty pool to rise (unlikely where I live in Southern California -- but I'll play it safe). Therefore I may need to keep the pump for 2 or 3 days.

Does anyone know if i can replace water effectively by turning on my filler line and letting water drain out the overflow. Since the water comes in on the surface and the overflow is also on the surface it seems like I might just be losing the new water. Maybe running the filter at the same time would circulate the water? I'd appreciate any information anyone has.

The pool is 17,000 gallons and goes from 3.5' to 8'.

Thanks,

Larry

Hi, Larry,

Can you backwash and dump your water that way? How about vacuum to waste?

If "no" on the above, can get the other end of a hose lower than the pool surface?.....so you can siphon. :)

PS - you got good advice on only draining half....better to be on the safe side

I was exactly in your situation about a month ago (CYA 150+, also high CH). So I rented a sump pump from a pool store and drained it until the entire shallow end was dry - I estimate 2/3 of the water out.

It took about 12 hours and my pool is a little larger than yours (20K gallons). Took about the same time to refill using garden hoses.

At the time, I was very concerned about this, but turned out just fine. Water has never been better; it's great to have everything back in balance!

Something to check: here in No. Cal. you can't drain the pool water down the street and into the storm drain; but, you can drain it to the sewer. Look for a sewer clean out and direct the flow there.

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Originally Posted by duraleigh

Hi, Larry,

Can you backwash and dump your water that way? How about vacuum to waste?

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I don't think I can backwash -- I thought that was for DE filters and I have the cartridge variety. I also can't get a hose lower than pool, so I'm stuck with one of the other 2 methods.

Larry,
Welcome to the forum.
On the draining...should be no need to rent a pump. Use the vacuum hose in the skimmer. Should let you drain well below skimmer level. Or, you can get a cheap Flotec sump type pump at Home Depot for $70 or so. Handy thing to have anyhow.
But...consider this....since you are looking for a major water change, some people have used a big plastic sheet to cover the pool as a separation membrane. If the width of the sheeting isn't enough you can tape sheets together using multiple layers of duct tape. Doesn't hold up long but will be good enough for the couple days it needs to hold. Cover the pool and start adding new water onto the top while you're draining out the bottom. 100% replacement. You never get a 100% replacement if the liquids mix. Another advantage is the water level never drops so you don't have to worry about floating the pool or liner. It does work. Saw a local with a new pool installation doing this last year.
Al

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Originally Posted by tmmort

I was exactly in your situation about a month ago (CYA 150+, also high CH). So I rented a sump pump from a pool store and drained it until the entire shallow end was dry - I estimate 2/3 of the water out.

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What was your CYA after the drain? I was anticipating I'd need more than one partial drain, but perhaps not. I did check the regs for where I live.

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Originally Posted by Poconos

Larry,
Welcome to the forum.
On the draining...should be no need to rent a pump. Use the vacuum hose in the skimmer. Should let you drain well below skimmer level. Or, you can get a cheap Flotec sump type pump at Home Depot for $70 or so. Handy thing to have anyhow.

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Thanks, Al. A couple of questions. I'm not sure what you mean using the vacuum hose in the skimmer. Also, for the plastic sheets do they just float on the surface? I have one of those kidney shaped pools.

I'm thinking of the vacuum hose setup that hooks to the skimmer. Should be able to hook it as you would for vacuuming but set the valve to waste and leave the hose in the deep end of the pool.

The plastic sheet will float. Just start filling on top and let it sink as you suck out the bottom. Shape of the pool shouldn't matter as long as the sheets cover the pool with enough overlap to account for dropping down as you fill.
Hope this answers your questions...if not...ask again.
Al

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Originally Posted by xcapecod83

What was your CYA after the drain? I was anticipating I'd need more than one partial drain, but perhaps not. I did check the regs for where I live.

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One pool store said 30, another said 50. When I receive Ben's kit I'll know for sure :)

I like Poconos plastic sheet method.

xcapecod83 - duraleigh's questions are excellent ones. Also, is your pool plaster or vinyl liner? If it is a vinyl liner pool, my understanding is that you have to be extra careful to keep your pool at least 1/3 full in order to keep your liner in place. Also, what method did you use to test that your CYA is 150? Are you positive it is that high?

Honestly Larry, my cya was easily as high as yours for the last two years. I dumped the pucks and went with liquid chlorine (before I found this forum--I actually got that advice from a smart person at a local pool store whose name starts with "L"!). It dropped a little last year. Then I put in an SWG so I didn't have to deal with chlorine (only acid) from then on. I started draining the pool but gave up because I know our groundwater is high here. There are several creeks in my neighborhood in N. California and I got nervous.

From this forum I learned that if I didn't have an algae problem, I could simply run a much higher free chlorine level and things should be okay.

Mother Nature took care of it this winter. The rains and chlorine demand from the winter debris dropped the CYA naturally and it is now 40!

Also, I do have a small ball valve with a hose bib connection installed on the pressure side of my circulation system. There is a sewage cleanout nearby so I can run a hose over there for winter draining. I can drain the pool through this as well, but it takes a loooooong time.

Al,
With a cart filter he may not be able to vacuum to waste. It seems a lot of pool installers, when they install carts, don't put 3 way or 6 way valves on them. My dad didn't have a valve for his DE filter, but the filter had a bottom drain he could use to flush it.
Do Carts have such a bottom drain?

I have a cartridge filter and you are right, there is no multiport valve for the filter. There is a drain port at the bottom of the filter.

Thanks for all the great information! My cartridge filter cannister has a drain plug so I can drain the water when I clean the filters. It's too big for a hose, but there's a drain near by. Can I drain water this way without damaging my system?

I don't know about draining through the plug. Maybe you can....

What I have is a brass ball valve with a standard hose bib thread on it plumbed into my system between the heater and the filter. I run a hose from that to a nearby sewer cleanout. With the pump on, I open the valve and it can drain the pool very slowly. Of course, I turn off the autofill with this setup. I am thinking that if I left the autofill on and closed the skimmer, I would be draining from the bottom and filling from the top I can do a suboptimal water change that way too.

Moot point for me since the rain dilution this year took care of the problem.

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Originally Posted by bbb

xcapecod83 - duraleigh's questions are excellent ones. Also, is your pool plaster or vinyl liner? If it is a vinyl liner pool, my understanding is that you have to be extra careful to keep your pool at least 1/3 full in order to keep your liner in place. Also, what method did you use to test that your CYA is 150? Are you positive it is that high?

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I'm using the CYA test in the Leslie's DPD test kit (the one where you add water until the black dot at the bottom of the cylinder disappears). I checked it twice.

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Originally Posted by xcapecod83

I'm using the CYA test in the Leslie's DPD test kit (the one where you add water until the black dot at the bottom of the cylinder disappears). I checked it twice.

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Great - I was hoping you were using the black dot test. I just wanted to make sure you were using the proper test, and not just a pool store printout or test strip, before going through all the effort of a drain/refill. As others on the post have said, if you get the CYA down between 50 and 100, you can certainly successfully run the pool (using the higher Cl amounts suggested in Ben's "best guess" table), so make your own judgement about the target level based on the amount of effort you want to put in, the cost and quality of your fill water, etc.

Good luck!

I have been battling an elevated CYA for the past month- found out it was elevated by chance- my pool store must not have tested for it because I never was told it was a problem. Reading of around 150. Have a fiberglass pool and was told by installer that I could not empty it more than 12 "- I have done that twice with very little inmprovement. I waqs swimming in the pool- which looks great by the way, I just have to keep using chlorine- am I in any danger using the pool?:

Couldn't you simply use two hoses: one is siphoning water out while at the same time a different hose is adding new water? This wouldn't remove CYA as fast (and you'd waste more water) but this would avoid having to empty the pool at all...

I've never needed to drain so I'm just hypothesizing that this method would work.. wouldn't it?

So, if you shouldn't completely drain a pool because ground water might push it up, how do you resurface a pool when it's time?

I believe one option is to dig a sump next to the pool and pump off ground water continuously during the refinishing process. In some areas, careful choice of the time of year to do the refurb can help.

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Originally Posted by Poconos

I'm thinking of the vacuum hose setup that hooks to the skimmer. Should be able to hook it as you would for vacuuming but set the valve to waste and leave the hose in the deep end of the pool.

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Can't vacumn to waste with a cartridge filter. I had to partially drain and refill my pool when they set up the SWG because they dumped in too much salt and my cell shut off with a high salt warning. I used a submersable aquarium pump (a very large one) and drained a foot below the skimmer. I then refilled and had to repeat this 3 times to get my salt levels in line. It is not necessary to drain all at once. You can drain a foot and refill until the CYA levels are where you want them.

Unless your pool is sitting way low you should at least be able to get a gravity flow drain going using a couple garden hoses. Run the water from the garden hose into the pool and run another garden hose out the pool. Get a flow going into the hose leaving the pool for 20 seconds and then the flow should continue. Also you can always use your filter pump but not through your usual vacuum setup through the skimmer. If you submerge the hose that usually goes to the skimmer under water you can pump water out of your pool for ever with your return line going to where you want to drain!