help with my numbers please?

Jun 22, 2010
39
We just filled the pool yesterday. My readings this morning were:
FC = 0, CC = 0, TC = 0, pH = 7.2, T/A = 40, CYA = 0
I think CYA probably was actually 0 because the solution was totally clear.
Per the calculator for 27000 gallons I added 64 oz dichlor this morning. The recommended FC level for shock was 10.

This evening (about 11 hours later) my readings are:
FC = 8, CC = 0, TC = 8, pH = 6.5, T/A = 50, CYA = 0
CYA may not be quite zero because the solution was a tad cloudy, but I could see the black dot with all the solution in the tube, it just was not quite as black!

We filled the pool with some lake water and some city water.

I guess I was expecting FC to be about 0 by this evening and to need to add more shock.
Do I bring FC back to 10, or give it more time with what I added already? The water is still green.
 
P.S. I have read the pool school and I know it says keep at shock level til clear, but I could not be home all day to keep a check. It was a hot sunny day and I was expecting a bigger drop in FC and don't want to do the wrong thing!
 
Have you added any CYA at all? If not, add enough for a level of 40-50. It takes a week for added cya to register. Run the pump/filter till it clears. Your green water may turn out to be metals. Lake water you say?????? Lord knows what could be in that. I'd shock it and keep there just for the lake water.
 
Since you have a new fill, you started with zero CYA in your water.

After you added 64 ozs of dichlor, your CYA increased to about 9. Make sure to take this into consideration when calculating the amount of CYA you want to add.

Keep track of what/how much CYA you add. It takes a while for CYA to show up on tests, so wait about a week after adding to test for it. Testing too early will only waste your reagents.

Using baking soda, I suggest you raise your TA to about 70.

Also, I'd raise the pool back to shock level of 10 again tonight.

Can you confirm your pH?
 
Even though it takes a week for the cya to show up on tests, you should assume it is active once it has dissolved and adjust your FC for the cya level you targeted.
 
Your green water may turn out to be metals. Lake water you say?????? Lord knows what could be in that.
My experience has been that lake water is a pretty good fill source. There's not enough of it (lake/pond water) used to be certain but it doesn't seem to have any metal content for the most part (I'm not sure why) and the algae and bacteria that are in there are normally very, very easy to control.

I have filled my entire pool with pond/lake water twice and I would do so again.
 
Is there any guideline for how long it should take to clear up? I brought the pool up to shock level again and had no overnight chlorine loss. (FC=9.5, CC=0.5 last night and this morning) I added stabilizer and got the pH back up to 7.5. We have been through 3 shock cycles but the water is still green and cloudy. I could see the bottom of the pool finally yesterday but I don't see any noticeable difference this morning.
 
If it were me, I would say never, pool store numbers will only confuse you, and the uncertainty of their test methods makes most useless. If you want to prove this to yourself take one sample divide it up and take it to 2 or 3 pool stores and see the spread yourself. Remember even after the algae is dead you still have to filter it out before the water will clear up, run your filter 24x7 and clean/backwash often. If you have no FC drop overnight you should be done shocking, it is just waiting for the filter to do its thing now. You usually get a color change (brown/gray) with dead algae, but not always.

Ike

p.s. remember dichlor and trichlor will raise your CYA, and it can take a week or more to show up on the tests.

p.p.s just to be safe I would consider boosting the FC a bit to about 15 ppm, since we are unsure of your effective CYA level due to the mix of dichlor shock and stabilizer, this should help burn off that remaining CC and give a you known good safe starting point. This may be overkill, but it is always good to start of a clean slate and not a low level algae problem you will find yourself fighting. Remember don't get CYA too high since this means drain and replace to get it lower.
 
My chlorine levels are holding so I think we are OK for contaminants that the chlorine needs to kill off, but the water is still green and cloudy. Possibly I am just impatient since we just got the pool filled 4 days ago! Here are the numbers this morning:
FC = 12, CC = 0, TC = 12, pH = 7.2, T/A = 70, CH = 30, CYA = 27

CYA may actually be higher. I added stabilizer about 36 hours ago with target of getting it to 30-40.

This is the first time I tested for calcium. Could that be the cause of the cloudiness?
 

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Keep the filter going.....I'm not sure with the lake water....My opinion if you had started with fresh water from the start you wouldn't be were your at now..I think it is better to spend a little to have fresh city water brought in for a fresh start than having the pain that you are having to deal with now...
 
Four days is not very long - I know it seems like an eternity - but in my limited experience a week is more realistic. Be sure to watch your filter pressure and when it goes up 8 to 10 do a good backwash. I found that when I was using pool store chemicals and checking my FC once a day it took a lot longer to clear than when I started following the procedure outlined in pool school. Go get yourself a lot of regular nothing added bleach- Walmart, Cosco, Sam's usually have the best prices. Use the pool calculator and every couple of hours bring the FC up to shock level with bleach. If you have today off it is a good time to do this. I bet by tomorrow morning you will see a noticeable change. Once the algae turns white or gray and begins to settle to the bottom you speed the process by vacuuming. If you can afford the city water, vacuum to waste and it will clear a lot faster. If you vacuum to waste you will probably have to replace a couple of inches of water. At any rate if you follow the advice given here I believe you will have a clear pool by next weekend at the latest.
 
My filter pressure has not changed at all. It started at 10 and is still at 10. I can see a difference now in the water clarity compared to this morning when I last posted, so I guess the filter is working. I looked at the flocculents at WalMart yesterday, but would rather avoid adding extra chemicals if I don't have to. I used dichlor shock initially because it came with the pool, but have only used bleach for the last couple of days. I bought a big bag of baking soda. I will use that today to raise the TA and the pH.
 
I think you are on the right track. Just keep FC at shock level today while you are home. I have used flock before. I don't think it helped get the green out. It may have helped with cloudy water, but I am not sure. I would just continue with what you are doing and as I said when you begin to see white or gray material on the bottom of the pool start vacuuming either to waste or filter. Sometimes when I vacuum to my filter I get material coming back into the pool from the return. City water is readily available to me so I just vacuum to waste and then replace the inch or two of water. I think some of that dead algae is too small for my sand filter to catch.
 
I realized after I posted that it was high CH, not low, that could cause clouding. POP is tough, but I think you are probably right.

I am confused about the need to shock. If I don't have overnight loss and CC is 0, is the shock just a precaution because of the cloudiness?
 
I'm not sure you need to shock. I would leave the PH and TA where they are for now, focus on one thing at a time.

Is this a brand new pool? or new to you?
You stated your FC is holding overnight, correct?
Is there a possible filtration issue? Have you examined the sand filter for problems - is this new sand? have you looked inside it?
 

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