Green pool and now my head is spinning

leanned · Postby **leanned** » Fri 10 Jul, 2009 18:50

My pool has been green since I opened it this year. I can't seem to get rid of the algae. I am in a catch 22...I have algae(or something green), I backwash, vac to waste, fill pool, backwash, vac to waste, fill pool..you get the idea(for 3 weeks now). I am brushing the sides and trying to stir things up but it's still green. I know my CYA levels are low but I was sick and tired of adding stabilizer when I was constantly having to refill the pool with fresh water to bring it up enough to run my filter. It was costing me a fortune but I think that is where my problem might be. So I shocked my pool and now I am off to the pool store tomorrow to buy stabilizer...I am assuming my levels are at 0 so ouch it will be a big bill. I have already added over 6kg of stabilizer at various points this year. Hence that is why I stopped until I get my algae problem cleared up. I added the sodium hypochlorite(20 L) 3 hours ago and I am not noticing a colour change yet, usually you see a change rather quickly.
So to make a long story short, I come to the website today and start reading the "pool school" and my head is spinning.....there is so much to water chemistry!!!!!! Then I started reading about borates and my head went into hyper drive. I am at a loss and have decided to ask you all for your help and suggestions.

Here are my pool stats to the best of my ability
18x36 inground vinyl lined pool with a Zodiac SWG, Hayward filter and pump
will be 3 yrs old this summer
Total hardness(as CaCo3) 500
TC 5(before shocking)
Free Chlorine 3
ph 7.2
TA 90
salt level is around 4000 I think
I use the strips...is this a reliable way of testing?
I live in Ontario, Canada and we have been having a cool summer with lots of rain. I wasn't putting the solar cover on but when I thought I was getting the algae under control I started. I have never tested nor has the pool store tested calcium separately or phosphates.
Thanks for letting me babble on.....

Swim Today · Postby **Swim Today** » Sat 11 Jul, 2009 15:40

All your levels seem in check. The CYA level even at zero is not going to effect whether or not you have algae or the clarity of the water in most cases. It acts as a sunscreen for the chlorine making it last longer in the pool. So no need to spend any more money on stabilizer now. The one thing I didn't see was if you tried an algaecide or not. If you have an algae you usually can't kill it through shock and chlorine alone as algae thrives in an acidic environment. Try adding a high concentrate algaecide like a mustard algaecide. That will kill the algae and then just vacuum it up as normal to remove it completely from the pool. Any local pool store should carry a high concentrate algaecide.

Bjorn · Postby **Bjorn** » Sat 11 Jul, 2009 19:28

Have you tried adding a product that combines algae together? The algae will collect on the bottom and then you can vacuum them up?

Postby **chem geek** » Sat 11 Jul, 2009 20:49

Swim Today wrote:The CYA level even at zero is not going to effect whether or not you have algae or the clarity of the water in most cases. It acts as a sunscreen for the chlorine making it last longer in the pool. So no need to spend any more money on stabilizer now.

Not true. If there is zero CYA (stabilizer, conditioner) in the water, then half of the chlorine (FC) will get lost to sunlight around every half hour in direct noontime sun so it is important to have at least a small amount of CYA in the water. At the other extreme if there is a high CYA level, CYA isn't just a "sunscreen" for chlorine -- it attaches to chlorine rendering it ineffective. In typical pool water with an FC that is around 10% of the CYA level, 97% of the chlorine is attached to CYA and the chlorine attached to CYA does not kill algae. Fortunately, it takes a low level of chlorine to kill pathogens and algae, but a higher CYA level will make chlorine less effective. If the FC isn't around 7.5% of the CYA level or higher, then algae can grow faster than chlorine can kill it unless a supplemental algaecide or phosphate remover is used.

The first thing to do is to get at least 10 ppm FC into the water and hold it there (maybe 15 ppm FC if your CYA is above 30 ppm). A higher level might be needed, but that's good to start out with. Second, is to get a good test kit since test strips are not accurate, cannot measure Calcium Hardness (CH) (they only measure Total Hardness), and bleach out at high chlorine levels. The problem is that the best test kit to get, the Taylor K-2006, is very expensive in Canada (sold here). As far as the pool school is concerned, you've got algae so just read Defeating Algae and don't get sidetracked with anything else at this point. You can try to dilute the water with tap water to have your existing "guess strips" measure the higher chlorine levels.

leanned · Postby **leanned** » Sun 12 Jul, 2009 15:01

Good news.....my pool is clearer!!!!! Finally the algae turned white!!!

I went to the pool store and tested my water...too my surprise my CYA was 40..needed 2 litres of Stabilizer to get it up to 60
my salt level was low at 3350 so 2 more bags of salt
the ph level was a tad high at 7.9 so I added a Litre of muratic acid.
FC was 4
I vacuumed it out this a.m and added the stabilizer and salt. I hope this gets things under control

Chem geek...a question for you....you say to get my FC to 10-15 ppm and hold it....my FC was 4 and the pool store was all worried that it was too high.....how much FC is too much. The store has me so worried about wrecking my liner that they only want me to add pidly amts of chlorine which doesn't work at all.

I will look for a better test kit, I always wondered about that..thanks for the link!!!

Thanks everyone for your suggestions and help, now all we need is HOT weather so we can enjoy the pool!!!!

Postby **chem geek** » Sun 12 Jul, 2009 23:09

You should not have increased your CYA level (at least not before you cleared up the algae problem) -- the pool store advice was wrong. It only makes it harder to clear the algae from the pool. They are also wrong about the FC of 4 being high, especially when there is CYA in the water. Wrong, wrong, more wrong, and totally wrong. You need to figure out who you are going to listen to because you aren't going to clear your pool if you listen to conflicting advice.

Now if your CYA is truly 60 ppm, you need to raise the FC level up to around 24 ppm to clear the pool quickly. You could target a lower level, but it will take longer. Technically speaking, having an FC that is 40% of the CYA level (which is what you do for shocking) is equivalent to a pool with 0.6 ppm FC and no CYA. The pool store simply does not understand this. You just need to be careful about adding any concentrated chemical and add the chlorine slowly over a return flow with the pump running and for extra safety, lightly brush the side and bottom of the pool where you add chemicals to ensure thorough mixing.

leanned · Postby **leanned** » Mon 13 Jul, 2009 14:08

the deep end is still not clear, I can see the main drain but not clearly. It's not green and not really cloudy just not clear. Tested with my strips and it says the levels are fine. FC is at 3, so should I add chlorine again, and if so, how much? Because I have a SWG I have tried to use the superchlorinate function but it never seems to give it the punch it needs to clear the pool. Sometimes I wonder if salt was the way to go for us, I don't seem to be saving any money or have the beautiful water they say you should have.
again thanks for letting me go on!!!

Postby **czechmate** » Mon 13 Jul, 2009 15:13

Richard is right. To have CYA around 40-45 is valuable. In case you raise it to a 60ppm you need 10-11% of that in available chlorine. That would mean at least 5-6ppm in chlorine. To me strips are waiste of money. Get yourself Taylor basic 3 bottle tester in Leslies for about 12 bucks. Fast, easy to read, and long lasting.
And ALWAYS listen to Richard(Chemgeek). He IS the wizard here.

leanned · Postby **leanned** » Mon 13 Jul, 2009 16:26

I have pretty much figured out that Chem geek(Richard) is the go to man on this site!!! I just wish our pool store would tell us the same stuff as we learn here, or at last part of the stuff we learn here. The store I go to just scares the crap out of you for using too much chlorine in your pool. They would like me to add only 10-15 L at a time to clear a 100,000 L green pool. So as a relatively new pool owner I was listening, now that I have found this site I will be more inclined to listen to what is said here. It just takes me a while to get my "school head" back on for learning again.

Postby **chem geek** » Mon 13 Jul, 2009 22:03

For an SWG pool, once you've cleared your pool it IS OK to have a higher CYA level, even 70-80 ppm if your pool gets a lot of direct sunlight, but you need to have a minimum FC of 4 ppm (the 1-3 ppm FC recommended by SWG manufacturers is NOT high enough). In a manually dosed pool, the target is higher, but SWG pools seem to do OK with a somewhat lower target. To be safe, you could target 5 ppm, but again this is after your pool is cleared. You could also consider using borates in the pool as this is a mild algaecide and pH buffer. More specific info for SWG pools in described in Water Balance for SWGs. I'm sorry there's a lot of reading.

Whenever you add concentrated chemicals to your pool, do so by pouring slowly over a return flow with the pump running. For extra safety (especially in vinyl pools), lightly brush the side and bottom of the pool where you've added the chemicals to ensure thorough mixing. This same rule applies to adding chlorinating liquid or bleach since these are denser than water until they mix.

bobbyg714 · Postby **bobbyg714** » Tue 14 Jul, 2009 17:23

leanned wrote:I have pretty much figured out that Chem geek(Richard) is the go to man on this site!!! I just wish our pool store would tell us the same stuff as we learn here, or at last part of the stuff we learn here. The store I go to just scares the crap out of you for using too much chlorine in your pool. They would like me to add only 10-15 L at a time to clear a 100,000 L green pool. So as a relatively new pool owner I was listening, now that I have found this site I will be more inclined to listen to what is said here. It just takes me a while to get my "school head" back on for learning again.

Yeah, I also realized that Richard is the go to guy. Richard helped me back in May with an Algae issue. I had algae for three straight years and was about to hang it up when I stumbled on this site. Not only did Richard solve my problem, he educated me in pool care and bleach, recommended a great test kit, and answered any question I had no matter how dumb it sounded. With his help and my new found knowledge, my pool has NEVER looked better than it does this year. Best of all, I haven't been inside a pool store all season. No need to ever go there again unless I need a raft or something.

Just wanted to thank Richard again for all he does on the board!

Bob

Postby **chem geek** » Tue 14 Jul, 2009 23:10

Your welcome, but my knowledge is cumulative starting from what I learned from Ben Powell and the mods at The PoolForum to people at Trouble Free Pool and other sites (such as PoolSpaForum that is more active about spas). There are a lot of very knowledgeable and helpful people. I've just focused mostly on the pool water chemistry aspect.