Advice Sought for Green Pool - Numbers Posted Inside

Hi guys:

I think I'm on the right track but would like some advice on getting rid of the green. :)

Concrete/plaster
Approx. 23,000 gallons
DE filter

Numbers from this morning:

FC: > 5ppm (my kit doesn't read any higher that that)
TC: > 5ppm
pH: 7.5
TA: 150 ppm

I can't do CYA because I'm out of the test chemical. :\

A little more backstory: I did a refill to start the season and had everything pretty well in balance. Then I had some things happen and the pool did not get chlorinated for a bit, plus the electrical box was having issues so the filter didn't run. It was enough for it to go green.

I've been trying to get TA/pH down with muriatic acid... Since last Friday or so I've gotten it down from over 200 to 150ppm. I'm going to keep adding more to try to get TA below 120 and pH a little lower too.

I also backwashed and put in new DE yesterday but pressure has risen some so I know I need to do that again.

Do I need to get more solution and start looking hard at CYA? Right now we've gone from deep cloudy green to light cloudy green. I've got tabs in the chlorinator, put in 5 gals bleach last night, and it also had 2 packs of super-shock yesterday.

Any thoughts/help greatly appreciated!

Yes, it is important that you know your CYA level. Do yourself a favor and get a good kit that will test higher than 5 and will include the CYA test as well. We suggest the Taylor K-2006 or 2006C (same kit with 2-oz. bottles instead of 0.75). Click on the Amazon link in my signature below. If you order through that link, the forum makes a little money on the sale. If the seller listed isn't Amato Industries, wait a day or two and check again. They seem to restock quickly when they sell out. We are finding that some of the other sellers are shipping the K-2005 which you do NOT want.

If you've been using trichlor tabs a lot, your CYA is probably pretty high. If your supershock is dichlor, it also adds CYA. I would suggest just using bleach at least until we know your CYA level.

So, until you get that good kit, do you have a reputable pool store that you can ask to test your water and then post them here for us to look at? Make sure CYA is one of the tests they do. (Just don't let them talk you into buying a bunch of stuff. They'll try!)

Thanks Watermom. I will get a CYA reading. I have to go to the pool store anyway to get more DE, so I'll see if I can get a test done then...

Ok, CYA is very low or zero, basically, so I guess the tabs are not a bad thing. Keep doing bleach at night? And add stabilizer to the skimmer?

Yes to all. However, since your pool is green, you need to shock up to about 10-12ppm and try and hold it at that level until the pool clear, you have less than 0.5ppm of CC and until you can go from sundown one day to within 2 hours of sunrise the next without losing more than 1ppm of cl.

Until you can get the good kit, you can force your kit to read higher by using a dilution method described here: Testing Without a Good Kit. It is not meant to replace having a good kit, but a "just until you get it" method. It isn't super accurate, but better than nothing.

Keep an eye on your pH. Trichlor tabs are very acidic.

Do us a favor, please. To make it easier for us to help, if people will create a signature line with their pool specs, it keeps us from having to reread through posts to find out basic information. You can create a signature by clicking on 'settings' in the upper right-hand corner of the homepage. In your sig, please put type of pool, volume, type of filter, size of pump, whether or not you have a SWCG or any water features and the fact that you do or do not have a K-2006. Thanks!

Thanks Watermom... I'll work on that signature.

Meanwhile, we're pretty much back to blue here, but it's still cloudy. I'm still bringing pH and TA down (should be down to 7.4 and 120 ppm, respectively, today). I'm going to do another DE backwash cycle and keep bleaching it at night. Anything else I need to do to get the water clear? Thanks, Mark

Run the pump 24/7. It takes time for a filter to remove dead algae.