Question about Cloudy pool after slight algae outbreak

[pool4me]

Hi all,

I had a question,

This year (we had a mild Winter here in PA). Last Thursday I pulled the cover off the pool and the water was very clear but had a slight green film at the bottom. No biggie, "this weekend, I'll pull the cover early and get everything going". (Even though the weather here got a bit cold again).

Well.... come 3 days later on Sunday, I open up to a pretty green pool. (Very fast - I was shocked - no pun intended). I'm sure I caught it early but WOW, did that move fast.

I've only had this once in the past and like the last time, I followed :
Turning Your Green Swamp Back into a Sparkling Oasis

AS USUAL - with the great advice in that thread, by last Wed, I had shocked the pool (since the previous Sunday - 3 days) , chlorine levels had stabilized with no real drop between my 9pm check and my 9am check on Wed.

So All is good, the water is a nice blue color, "milky look" is gone etc.

To play it safe, I keep shock level at 30, 2 nights after my levels had stabilized. (taking me till Friday when I check again and see no real drop from the night before). All my levels now are at my desired levels from the chart I keep and all is good. (By the way.. time to order more supplies for my TF-100 from all those drop tests.)

Every day since this Thursday I see an improvement. (Filter has been running 24/7 Since last Sunday). Everything has been "stable" since Thursday/Friday. Judging by the visible area of the border and pool walls, I see a bit further to the bottom every day since Friday and while brushing, I can just see the brush as the bottom now as of today.

I'm using a Sand Filter and I know this can take a bit longer to clear up the water. I've also added a little over a 1/4 cup of DE mixed with a gallon of water and added it to the skimmer (Pressure Increased about 1psi). Normally I don't use any DE, - the filter has been doing just fine on it's own.

Just wondering how long most of you using sand filters seem to find it takes to clear the water?

I'm about 100% sure everything is dead. (I can post some updated numbers tomorrow). Right now, I'm NOT using the SWG but have been using bleach and I've noticed the the high chlorine levels have now drifted down to about 7ppm. I also have a Trichlor puck in the skimmer for no other reason than it makes me feel better

(I'm leaving the level a bit high at this point but I'll let it come down to 3-4ppm in the next few days and then when everything is clear, I'll add salt and fire up the SWG.

Just wondering about the time to clear. I'm guessing another 3-5 days or so using a sand filter?

 

[linen]

Depending how much algae you had i there to start with it can take awhile. My experience is about a week once the stuff is dead if the filter is working correctly (i.e. not channeled, etc.). How long did it take you last time?

I noticed you sig confusion on pool volume, and I am confused. What is the 5.9 factor in your calculation? This might be where your numbers disagree with the pool calculator, since that uses 7.48 gallons/cu. ft. Also, even though you have a 52" sidewall, you don't fill it to the top (I assume that is the 4.3?). Typically the average level is ~6" below the top so your pool depth would be 46". With those numbers I get: (pi*(15/2)^2+(33-15)*15)*46/12*7.48= 12,808 gallons which is about what the poolcalculator gives. If you keep your pool water depth a little deeper, say 48 inches deep, then you would be about 13400 gallons, but don't forget to subtract what ever sand base/foam you have on the bottom that takes away from your depth. Best way to get your depth is to use your brush/vacuum pole and measure the water depth inside the cove when you have the water level where you typically keep it in the skimmer.

 

[duraleigh]

Just wondering how long most of you using sand filters seem to find it takes to clear the water?

I can't put a definitive date on mine, either. There have been times when it seems to clear very quickly and other times when it drags on.

For what it's worth, I think sand will clear a pool very well on it's own and, in the beginning stages of a real mess, a sand filter has a decided advantage in it's ability to hold a lot of junk.

Some folks have put clarifier in the pool when they seem to be "stuck". The results reported on the forum seem to be less than 50-50 as to whether it did any good...most say no but some say absolutely.

 

[pool4me]

Thanks for the info guys. On my way out now to check and see what it looks like.

Linen, I use 13,200 to play it safe(when calculating shock values) so you're right on the money. I've seen 2 different calculations / multipliers used on oval pools in the past (have the info somewhere) so I seem to come up with exactly what you mention 12,800 to 13,200 depending on the calculators and of course the water fill depth. (I stick with the 5.9 number). - and I should change that in my sig come to think of it.

Initially, my 33 x 15 x 4.3 x 5.9 = 12,558 in my sig, I was comparing to The Pool Calculator which seemed to come up = 14,400 for some reason.

For my "general pool care" I seem to base all of my numbers etc off of 13,000 gallons and I almost never have any issues at all.

In the past (only had one time to compare it to) it has taken about a week or a bit more to clear so I'm not exactly worried, but I just had it in my head that since this time it was only a matter of days between a clear pool with green film on a few spots on the bottom / and a pretty green looking pool 2 days later, that I caught it pretty "early on" and it wasn't "as bad". (however, I guess that's really had to say.... I guess if it's green, it's pretty bad by the time it gets that way).