Dead Algae. Pool blue but cloudy won't filter

[Patty16]

The story......

I opened the pool this sping and it was literally black with Algae. Started Shocking heavily every day for a week. Pool cleared up but still had a green tint. FC would not hold for more than a few hours. Continued shocking and using algecide and FC started to hold. I could see the bottom of the shallow end. PH and Alkalinity were low at this time. Decided it was time to vacuum but forgot to vacuum to waste and the pool became a mess again with loads of algea that was still living at the bottom.

So now I restarted the shock and algecide treatments and killed off the Algae. Vacuumed to waist a few times and began rescrubbing and vacuuming daily. Once the FC stayed over night got PH to 7.5 and TA to 120. It has been about 2 weeks at this point.

Everything is looking up EXCEPT you can't see 6 inches down. My filter has now been running 24/7 for a total of 3 weeks since we opened. Its now been over 1 week since the pool has been blue and all levels perfect and still too cloudy to see.

What am I missing? Should I kill the pump and just let the stuff settle and vacuum to waste? Not sure what else to do as the filter seems to be doing nothing. BUT it was when I first started shocking as I could start to see the bottom of the shallow end. So I guess I am not sure if its a filter issue or if it is just that the dead algae is so fine that it won't filter

Any help is MUCH appreciated!!

[aylad]

What size pump, and what size/type filter do you have? Many people are having this same trouble this year, and a lot of them have oversized pumps that are pushing the dead algae straight through the filter and back into the pool. If that's the case, you might do better to turn it off and let it settle to the bottom and vac to waste. If that's not the case, and you have a sand filter, you can DE test it (pour a cup of DE into the skimmer and watch for it to come back through the returns) and then use a little DE to help you trap the smaller stuff.

Do you have a working pressure gauge, and if so, is the pressure rising as you are filtering?

[Patty16]

Its a sand filter. I did read about the DE test and was going to give it a try.
Pressure gage was definitely increasing in the beginning and I was backwashing quite a bit. BUT I haven't backwashed in about 4 or 5 days and no the pressure hasn't gone up much at all. It starts around 11 and never really gets higher than 18 or 19.

I shut the filter off tonight around 6 PM. I am interested to see if that makes any difference tomorrow morning

P.S. How can I use a little DE to help with a sand filter?

[aylad]

AFter you test it to make sure that the DE won't blow through the returns, check your filter pressure. The other 3 mods, and some of the long-time members, add enough DE to their skimmers to make the pressure rise by 1 psi (if you get too high a rise, just backwash it out and try again--note it may take up to 20-30 minutes to see the rise, so don't get in a hurry). The DE coats the sand, making it "dirty", and it helps filter smaller particles that way.

[Patty16]

Thanks Aylad!

One more question. I will do the DE test but also wanted to get thoughts on using a floc at this point. I know most on this forum don't like it or use it as a last resort. But I am getting desparate. Even if the filter has an issue I can't get it fixed for at least two weeks as all the pool service companies are booked. I need to do something to make it usable in the meantime.

I have heard that floc is designed to address my problem but many are reluctant to use it. Why is this? I have been fighting this for almost 4 weeks now and I am getting mucho discouraged! Need to do something that will give me some hope

[Watermom]

Try the DE first and see if that makes a difference. Flocs sometimes help but other times make things worse. That is why we are often reluctant to advise using them.

[Patty16]

Thanks everyone for their comments!

I wanted to send an update. I did the DE test and it seems the filter is working as expected.

Knowing my levels were good and the algae was dead (FC above 12 for 3+ days). I decided to try using FLOC. Shut filter off. Put the floc in around noon time Wednesday. Thursday morning I could make out the bottom of the shallow end. By Thursday afternoon I could almost make out the bottom of the deep end. All of the sediment was in a layer on the bottom of the pool. Looked like a glaze. Thursday evening I vacuumed to waste. (Took me about 2 hours....slow process). The process did stir up the bottom and re-cloud the pool but not nearly as cloudy as it was. I could always make out the shallow end. After two hours of vaccuming, I turned on the hose to re-add the water lost when vacuuming to waste. Turned the filter back on and this morning (Friday) the pool is crystal clear!!! There is still some sediment that fell to the bottom again that will need to be vacuumed but for the first time since I opened the pool a month ago I can see the main drain in the deep end! Very exciting.

A couple of comments to those who may decide that a floc is there last option

1. Get the PH up to the recommended level listed on the particular floc because the floc will drop your PH (and it won't work well if the PH is not right)
2. Shock your pool the night before you flock as I was not able to run my filter for about 32 hours and my FC did drop pretty low as it was sunny for 2 days straigt
3. VAcuum to waste is a slow process and you need to take your time otherwise it could make a mess

I understand why folks use a floc treatment as a last resort as it is a pain and alot of work....BUT worth it if done right and you have no other choice.

During this process I did speak with a couple of folks who deal with filters and the response I got was that this is somewhat common with sand filters. If the dead algea is degrades such that the particles are really small many sand filters simply can't get it. It appears this was the case with me as I ran the filter for well over a week with zero change during this time. It was simply recirculating the dead algae.

Anyway thanks for the help from the forum. I have learned alot in the process.

Mostly that I NEVER want to deal with this again.

Don't let your pool get algae and u won't have to!!

Here's to clear swimming!

[BigDave]

Congratulations!
Thanks fot the follow-up. It's great to hear success stories.
Have a great summer!

[Watermom]

I have learned alot in the process.

Mostly that I NEVER want to deal with this again.

Don't let your pool get algae and u won't have to!!

You got that right!