All levels normal, pool still dark green

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So my husband had to leave on a trip and left me to finish the filling of the pool and retesting of the pool. We have done nothing except add water and bleach. The pool is now full again and the test results are below:

FC= 22
CC= 0
CH= 200
TA= 100
CYA= slightly under 100
PH= 7.8

He told me if the numbers are good to add the DE.

edit: she misreported the numbers. Changed CC to 0 and then made CH = 200
 
If you are sure your water sample you tested was from a well mixed pool (old and new water) then sadly, you need to do another drain/refill. A CYA of 100 is high and will make your SLAM you need to do difficult.

Sorry. Up to you.

Take care.
 
It can. It might be a bit lower than what you read.

Your shock level FC for a SLAM is 40% of your CYA. So say it is 90, that makes FC of 36 you will need use. Possible. But difficult.

If you plan to try, get a 5 ml measuring device from a pharmacy. Then you can do 5 ml FC tests were each drop of reagent equals 1 ppm FC.

Take care.
 
mknauss said:
Good to hear.

Good luck.

Remember from a previous post --

You have a vinyl liner pool. So the most you can drain at one time is only to the point of leaving 1 foot of water in your shallow end. Do you have a shallow water table (water in the ground near surface)? That makes a difference.
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What impact does shallow water table have on draining the pool? Would you still drain and leave a foot in the shallow end or do something different if you have shallow water table?
 
If the ground water level (water table) is higher than the level of the water in the pool then the liner will float. The ground water pressure will be greater than than the water that is in the pool. Fixing this is a pain as you have to reset your liner. It is possible to use sand bags to set the liner back into place as the ground water retreats or as you fill the pool with more water, but it is not easy. That is why I will never drain if there has been a recent heavy rainfall.
 
Bandit5 said:
If the ground water level (water table) is higher than the level of the water in the pool then the liner will float. The ground water pressure will be greater than than the water that is in the pool. Fixing this is a pain as you have to reset your liner. It is possible to use sand bags to set the liner back into place as the ground water retreats or as you fill the pool with more water, but it is not easy. That is why I will never drain if there has been a recent heavy rainfall.
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Got it, thanks. When I had my pool installed about 10 years ago and knew nothing about pools, The PB told me if they hit water, they needed to charge me an extra $800 to install some sort of drain. Not sure exactly what they did, but they did hit water after about 4 feet. So technically the shallow end is above the water line, the deep end is not but they installed some sort of drain (or what ever it is they needed to do).

Not that I need to drain, but just wanted to understand what (if anything) I need to be aware of.
 
See post #44. CYA of 90, shock FC of 36 -- your choice. Best to drain / refill again, but your pool.

Take care.
 
It can be done with your CYA that high but that is going to be a LOT of chlorine/bleach :( It is up to you but if it were me I would do another drain. We will support you no matter which way you decide to go. :hug:

Kim:kim:
 

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Looks like the math worked. Starting CYA was 150, I removed/replaced 1/3 the water and it is now 100 so we're draining and refilling again. I expect CYA to be somewhere between 60 and 70 this go around.

An interesting note, without adding any bleach at all the FC went from 22 to 25.5 over the course of a day. Any explanation for that or just measurement errors? My wife did the test yesterday and I tested today (both tests around 9am). Even with that much FC the water is still dark green and when I backwash the sand filter the spyglass isn't appreciably dirtier than the common pool water.

Our home is built on a hill, and the pool is at the highest point of the hill (well above street level, the deepest part of the pool is higher than the floor of my basement) so I suspect the bottom of the pool is well above the water table (or my yard/basement would be under water, right?) Is my assumption correct about the water table, and thus is it safe to empty the shallow end of the pool?
 
With just adding new water could be not mixed well or testing error.

Your FC is not high enough to kill the algae yet.

With your next drain refill you will be at CYA of 70. Shock level FC of 28. If that is your stopping point, then plan ahead for chlorine needs, testing reagents, etc.

Take care.
 
msdunkel said:
My guess is you're going to tell me to reduce the pH and SLAM, let's see how much I've learned over the past couple weeks of skimming the forums and listening to your sage advice:

After refill #2...

FC: 22
CC: .5
CH: 125
TA: 100
CYA: 70
pH: 8.2
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That depends.... what's your water look like now? If you don't SLAM, you'll still lower that pH, right?

Maddie :flower:
 
I am surprised no-one mentioned this but you can replace water in a pool without lowering the pool level. I do this every other year or so.

Refill Experiment

My last refill about a year ago, I was able to replace about 90% of the water before it started to mix.
 
msdunkel said:
Still dark green with algae growing everywhere. Oddly enough nothing sticking to the sides of the pool or the ladder. Just lots and lots of green algae resting on the entrance steps and bottom. Very easy to brush but too fine to be vacuumed.
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Well darn it all, then ya gotta do it. SLAM away. At least its not great swimming weather, huh? I swear it feels like October already in Georgia. Weird.
 
I got the pH down to 7.2 and probably added a bit more chlorine than required to get the FC to 28. How long should I wait to verify I'm at 28 or higher FC?

edit:

waited an hour and checked. Overdid it a bit and sitting at 34. I'll check it again before I go to bed :)

Pre-bedtime check: FC 35 -- magic pool that makes chlorine!
 

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