Draining Pool — Backwash or Pump?

MugZona

Well-known member
Jun 23, 2014
73
Tucson, AZ
Another newbie question: I've mentioned in another post, I'm draining my pool tomorrow. I've read that backwashing and a submersible pump are two ways to do this. Is backwashing a desirable way to do this? With my filter (Pentair Clean & Clear 320) is it even possible? My water looks good but as you can see below, it's not in operable shape:

TF-100 results:
FC=2
CC=.5
CYA=240
CH=2100
PH=7.2
TA=140

Thanks!
 

Sminor

Well-known member
Jul 4, 2011
137
Perrysburg, OH
Most cartridge filters don't have a backwash or waste feature but it should have a drain near the bottom... If you hooked up a hose to the drain somehow you could use your pool pump to drain quite a bit until the level gets too low. Then you would use a submersible pump to finish it up...
 

Zindar

Well-known member
Jun 4, 2011
209
Austin, Texas
I have a tiny pump the size of my fist, that screws onto a regular garden hose. It seems like one strategy is to get a bunch of garden hoses, and use the small pump on each hose, one at a time, to start a siphon going, then once all the hoses are siphoning water, disconnect the small pump, and let gravity do the work. The more hoses, the faster then draining.
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
43,238
Tucson, AZ
I have a tiny pump the size of my fist, that screws onto a regular garden hose. It seems like one strategy is to get a bunch of garden hoses, and use the small pump on each hose, one at a time, to start a siphon going, then once all the hoses are siphoning water, disconnect the small pump, and let gravity do the work. The more hoses, the faster then draining.
That only works for above ground pools ... or places where the in ground pool is on a hill.
 

Zindar

Well-known member
Jun 4, 2011
209
Austin, Texas
That only works for above ground pools ... or places where the in ground pool is on a hill.
Yes; my last pool was an in ground pool. I just assume that most in ground pools are not too far away from lower ground, or storm water would always funnel towards the pool, which doesn't seem good. Admittedly, if you have to run a hose to the front yard, that'd be kind of a long hose. It would work, but having a bunch of hoses that long doesn't seem practical, I admit. You could do it with one hose, but it'd be slow.

In my case, there was a storm water gully only maybe 40 feet from my pool, so it wasn't so bad.

Edit: Wait, I think my reasoning is full of holes... you'd need the lower ground to be as low as the bottom of the pool, which might not exist anywhere close, maybe not even in the front yard. Sorry - I guess my idea will certainly not work for many in ground people.
 

MugZona

Well-known member
Jun 23, 2014
73
Tucson, AZ
Just an update... Finished draining with a pump rented cheaply from HD, and now filling it up! Draining was easy, and I got a nice steady drizzle from the sky to keep the pebble moist (not sure it was necessary), and an overnight low of a cool 72. High tomorrow only 89 -- I think the pool will make it! (And yeah, my pool is definitely the lowest thing on the block, so pump was needed.)
 

MugZona

Well-known member
Jun 23, 2014
73
Tucson, AZ
Drain and Refill Almost Done — Next Step/

Hi all,

Just about completed my refill after draining most of the pool with super high CYA and CH, and it is probably at about 85-90% refilled now. I jumped the gun and did the test so I can get prepared for what to do next (so these numbers might change slightly but I would doubt much):

FC: .5
TA: 190
PH: 8.5
CYA: 30
CH: 700 (was hoping to knock this down more — stinking hard water)

What should I do first this afternoon — muriatic to lower TA and PH? I can't seem to see on Poolmath what effect muriatic will have on my TA — just on my PH. How long should I wait to test after adding acid? When should I add chlorine? Water clear right now.

Also, I live in the Arizona sun — when to add a little more CYA? (I have tabs left over from the previous owner, but can't seem to see on Poolmath the effect of dichlor/trichlor by weight on CYA.

Thanks!
 

Nuvene

Well-known member
Jul 5, 2013
116
Gilbert, Az
Re: Drain and Refill Almost Done — Next Step/

first thing would be to lower PH and add chlorine... the TA will go down as you keep lowering the PH... I have 800 CH in mine right now too... im hoping to acid wash then refill and lower that once it cools off (my pool feels like sandpaper and we always get out with bleeding toes)

On the CYA once you get everything else balanced you can add 10ppm a week till you find a happy balance between FC requirements and FC usage by the sun...

I would bring the pool up to slam level once just to make sure there is nothing in the little water left (i do this anytime i accidentally left my FC drop below minimum...
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,930
San Dimas, CA (LA County)
Re: Drain and Refill Almost Done — Next Step/

pH first. Don't try to get down to 7.2 all at once - you may overshoot. Target 7.4 or 7.5. Get that mixed up with the pump and a brush and then raise the chlorine up. Brush some more. After it's all had a long time to mix-- a couple hours --run your full set of tests and fine tune things. If the water is clear and there's no CC, I'd hold off on the SLAM. It'll just slow down the pH adjustments.

I see Effects Of Adding Chemicals show that the amount of acid to get from 8.5 to 7.4 will lower TA by about 17. Each 8 oz puck of trichlor will raise CYA by 2.5.
 

danacc

LifeTime Supporter
Jun 29, 2013
269
Re: Drain and Refill Almost Done — Next Step/

As noted above, pH and FC are your most immediate concerns. You're going to have to pay close attention to that pH for a while given the high CH level and currently high TA. TA will come down as you keep pushing the pH back down.

In sunny Arizona, I wouldn't wait on raising the CYA to at least 50. In PoolMath, put in the size of your pool in gallons, and then scroll to the bottom. There is an area called "Effects of adding chemicals". You'll need to know if those tabs are dichlor or trichlor (they are probably the latter). You can put in the weight and type, and it will tell you what effect that will have on the water.


Edited to add: I wouldn't SLAM, either, unless you see some reason to do so (water not clear, CC>0.5). You'll lose visibility to pH, and you need that right now.
 

MugZona

Well-known member
Jun 23, 2014
73
Tucson, AZ
Re: Drain and Refill Almost Done — Next Step/

Thanks everyone! I will go for PH first, and I'll keep this thread posted if I have any issues.
 

MugZona

Well-known member
Jun 23, 2014
73
Tucson, AZ
Re: Drain and Refill Almost Done — Next Step/

OK! I added muriatic, brushed, added bleach, brushed, and pump's been on. Here's the latest results:

FC: 3.5
CC: 0
PH: 7.2
TA: 140
CYA: 30
CH: 675

So... what should I do next? Thanks so much everyone!!
 

MugZona

Well-known member
Jun 23, 2014
73
Tucson, AZ
3 questions oving Forward WIth Newly Filled/Balanced Pool

Thanks to many of you for helping me very quickly and cheaply get my pool in balance after a drain/refill!

A few questions moving forward:

1) With my CYA now at a manageable 30 (was 240), is there a target range given that I'm in Southern Arizona? Should I try to bring it up right away to 40 or 50? I'm curious on hearing various opinions, including those who have many hours of sun exposure on their pools daily (and keeping in mind that I could use the occasional puck for vacations).

2) For my nightly bleach additions, should I be aiming for to the "Target" FC, slightly above, what? Should pump be running during chemical addition?

3) Related — what hours of the day, and for how long, should I run my pump? (Same question re: the Kreepy Krauly, which likes to be a jerk and hang out on one side of the pool, or get stuck up on the wall?)

Thanks!!

Matt
 

MugZona

Well-known member
Jun 23, 2014
73
Tucson, AZ
Re: Drain and Refill Almost Done — Next Step/

:cool:

- - - Updated - - -

Thanks Nuvene — in terms of finding that CYA/FC balance, how do you map that out? Is it a matter of thinking about FC goals over the course of a day (X in the morning, Y at sunset, Z after nightly addition) and seeing what CYA gets you to that point with the least bleach use?