Draining a pool to reduce salt

[JasonLion]

That is fine as long as there is enough room between the filter and pump so the water doesn't run over the pump on the way to the ground.

The plumbing between the skimmer(s)/main drain and the pump needs to be intact to prevent the pump from drawing in air. But you can do anything you want on the pressure side of the pump without a problem.

 

[ddas]

Thanks JasonLion.

My filter and pump are right next to each other -- a bit of water might run over the pump -- what difference would it make? (The pump is sealed...)

I'm a little nervous to run the pump while the filter is open but if you think it's OK, and as long as I make sure the water level in the pool is such that the pump is still drawing in water and not air, then I should be OK?

I'm hoping to only drain a small amount -- maybe take it down to the level of the skimmer's draw (just above, obviously, as I wouldn't want to go below, otherwise it would be sucking air).

 

[YippeeSkippy]

Small sump type pumps are handy to have such as this situation. You can drain a bit by placing the pump on the stairs in the pool and pump away. That way you avoid messing with the DE filter all together. They don't cost too much.
Another useful use of the pump is when you want to aerate your water and have no fountain or other means. We just put the pump on the stairs and use velcro strips to tie the small bit of hose on the grab bar and aim the water back in to the pool to aerate. Works like a charm and cheap.

 

[techfan]

I accidentally added too much salt to my pool. (I added, and my Jandy kept misreporting the correct salt amount, over the course of a couple of weeks, until it was too late and now I know.) So...I'm going to have to drain it, at least partially, right?

Any recommendations on how best to do this? Does salt typically settle to the bottom, in other words, if I drain from the bottom, am I best off draining before the pump begins running in the morning, so that the majority of the salt is sitting at the bottom and that's what gets washed out?

My salt cell has been very temperamental and might have reached the end of its life. Is there any harm in not draining the pool, leaving the SWG at 0% chlorine production, and just having a traditional chlorine pool for the year, and revisit this next year?

I have a 15k gallon pool and the salt concentration, as best I can tell, the salt reading is somewhere around 6000. The calculator is telling me, to get it down to 3000, I'll have to dump 50% of my water. How accurate is that calculation? How can I do this in the most intelligent way? If I really have to replace 50% of my water, it will cost me about $1500 (!!) in a water bill.

My city requires a $28 permit for any quantity of pool draining, plus I'm in California so am very conscious of the water shortage and would like to really figure this out as best as I can, so I don't make any more mistakes.

Any advice?

It must be in the air in CA. I live out by Corona and I have a similar problem with my Jandy 1400. I too dumped a lot of salt in the pool over the course of the last 6-8 months. Now I am worried about draining the pool and then refilling it. Already last year, I took my gardener's advice when my grass was near death and my HOA was all over me over brown grass so, I overwatered my lawn and got a bill of $400 for that mistake. I think I hit every tier water rate for that mistake. Also, my water company told me that in the event of a water shortage this year, they are going to raise the rates by 300% for the tiered levels so, I guess I better do it sooner than later. Let me know what your outcome might be with all of this and I will share mine as well.

 

[techfan]

fyi:

Called my water municipality. If I need to drain the pool, they have a once every 5 year allowance for that purpose and they will sell me the water at a Tier 2 rate. Tier 2 cost is somewhere around $2.50 per unit so, the cost would be around $35.

 

[ddas]

Well, that's a relief techfan.

I'm in a holding pattern. My handyman just told me he has access to a small pump, so what I plan to do is try it, drain a portion of water (perhaps just down to the bottom of the skimmer), and refill it, and see how much that brings down my salt. Then repeat it again as necessary to get it closer to 3.5 or 4. I'll update the thread as new issues come up! (They always do...)

 

[jblizzle]

Well, that's a relief techfan.

I'm in a holding pattern. My handyman just told me he has access to a small pump, so what I plan to do is try it, drain a portion of water (perhaps just down to the bottom of the skimmer), and refill it, and see how much that brings down my salt. Then repeat it again as necessary to get it closer to 3.5 or 4. I'll update the thread as new issues come up! (They always do...)

It is pretty easy to estimate. If the average depth is 48" ... and you drain 4" ... that is 1/12 ... so your salt will be 11/12 of what it was or 91.7%

 

[ddas]

Yeah. My salt concentration is at 6. I need to get it down to (at least) 4. So clearly I'm probably going to have to drain 1/3rd of the pool in total. I'm just hoping to do it a little at a time, to keep my water bill lower, to not have to constantly pay a pool drainage fee, and to control the salt level.

Coincidentally my calcium hardness is also extremely high so this might be win-win.

 

[jblizzle]

What the heck does at a 6 and need to be a 4 mean?

 

[JasonLion]

There is another scale where salt of 1,000 is noted as 1.0. Thus, salt is currently 6,000 and needs to be lowered to 4,000.

 

[pooldv]

The issue with draining a little at a time is that it will ultimately cause you to use more water than if you do it all at once. Here's why. If you remove 10% of your water you dilute 10% of your salt. But then you refill the pool and dilute the salt percentage. Which causes you to have to drain more and more water each time you drain because the salt is more and more diluted with each additional drain and refill.

 

[ping]

You might want to get this done now as Gov. Brown just signed a bill for mandatory water restrictions. It will take a little bit of time before the water agencies come up with their plans for cutting water use but I wouldn't wait beyond this week to get it done.

 

[ddas]

@JasonLion: yes, exactly -- I meant 6000 and 4000. (My salt unit shows it as 6.0 so I was just using shorthand.)

@ping: good point.

@pooldv: I thought that too but after thinking through the math, am not sure that's truly the case. Just to take round numbers:

1) I drain 10% of the pool. I'm now left 90% of the original water, and 90% of the original salt.
2) I refill it with fresh water, so now I have 100% of the water, but 90% of the original salt.
3) I wait a few days until everything has mixed thoroughly.
4) I drain 10% of the pool. I'm back to 90% of the original water, but I should now be at 80% of the original salt.

No?

 

[JasonLion]

Two 10% drains require 20% of the water, but leave you with 81% of the original salt. On step 4, you have 90% of the 90% of the salt left, which is .9*.9 or .81 or 81%.

Sequential small drain/refill cycles are not as efficient. However, they come pretty close as long as you are only replacing 50% or less of the water and are still tolerable for most people at 75% replacement. Try to replace 90+% with a sequence of partial drains and you waste a lot of water.

 

[ddas]

10-4. Thanks JasonLion. All this help is GREATLY appreciated.

My handyman says he has a small water pump he's bringing me tomorrow, so I'm hoping to drain as much as I can tolerate in one go, refill it, then wait for the salt to recirculate, stabilize, and measure it accurately so I can see exactly how successful I was. Then, if I have to do a second or a third partial drain, I'll know what I'm up against. (I wasn't literally suggesting a 10% drain -- I was just using round numbers for illustration.)

 

[pooldv]

Ok, yeah, those numbers make sense, it isn't as bad as I first thought. I was trying to get back to poolmath to do some calculations to validate my theory, but got way busy. Good luck!