Newbie's green pool

[George in Georgia]

I'd started this a few minutes ago, but something went wrong!

I've got green water. While searching the net for help, and after enriching my local pool store, I found you guys. Why should the pool care whether the hypochlorite ion is attached to a sodium ion or a calcium ion? Inquiring minds want to know.

A few details:

25,000 in ground, vinyl
SWG
Sand dollar 60 filter, new sand, Challenger 1 hp pump

Pool shop test results:
Saturation index -.8
TDS 4500
CYA 90
Tot Cl 1
Free Cl 0
pH 7.8
Tot alk 50
Adj tot alk 23
Tot hard 75
Salt 3100

So far the store has had me using A LOT of 48% cal, and most recently something called Swamp Treat (no ingredient statement either on jar or website) and a good deal of trichlor, probably the major source of the cyanuric acid.

The only removal of green has been from my wallet!

Monday they did a 4 hour test of a sample, I guess to measure chlorine demand.
After that test their recommendation is 28 lbs of 48% cal, broken into 3 doses 3 or 4 hours apart, 10lbs, 10lbs, and then 8lbs, dissolved in water before adding to the lime jello pool. This would be around $100.

Working with that 28 lb figure and The Pool Calculator it looks as though 36 or 37 96 oz jugs of 6% bleach might do the job. Does this seem about right? Should I follow their schedule of application for the bleach, 12 gal every 3 or 4 hours, with frantic brushing, of course?

When I told the pool store that I was investigating household bleach they were incredulous, to put it mildly. But with a vinyl liner I don't need calcium ions, they'll only gunk up the SWG.

I'm really glad I found this site! One not to be named pool store person recommended copper algaecide even though I told them that I though the copper would plate out on the salt cell. Geez!

Any help, advice, hand holding y'all can give would be much appreciated!! Thanks!

[sturev]

your other post is here: http://www.poolforum.com/pf2/showthread.php?t=10042

[aylad]

Wow, I'm glad you're here, and know better than to keep making that pool store richer without getting a clear pool!!

You were absolutely right not to add the copper algaecide, and that all the trichlor is probably the source of your high CYA. However, depending on what SWCG you have, this is one of the situations where having a high CYA is actually a good thing!

In a pool your size, using 6% bleach, you can raise your Cl to 20 ppm by adding 8.5 gallons. With a CYA that high, you need to shoot for between 20-25 ppm and consistently keep it there until the pool clears up and you're no longer losing any chlorine when you test at night after the sun is down and again in the morning before the sun hits the pool. The key here is consistency, so you'll need to test and add more bleach each time to get back up to the 20-25 range. Each 1/2 gallon will raise your Cl by approximately 1 ppm, so you can use that as a guide when retesting. Brush the pool daily, keep the pump/filter running 24/7 and backwash the filter as your pressure indicates. I would not use any more dichlor shock--I would just use bleach to get the pool cleared up, and then the SWCG should be able to take it from there.

Your pH is a little high, you might want to lower it using muriatic acid to 7.2-7.4. Keep in mind that while your chlorine is at shock level, though, the pH probably will give falsely high test results, so you might want to adjust that first.

I would absolutely not put any more of the Swamp Treat (especially since there's no listed ingredient ) or anything else in the pool other than acid and lots and lots of bleach.

We're really good at hand-holding around here, so shock the pool and keep us updated on how it's going!

Janet

[sturev]

You might check prices and compare the price of regular 6% bleach and 12% chlorine in your area... since it looks like you're going to need quite a bit, it might be cheaper to go the chlorine route. The pool store should/might carry liquid chlorine

[George in Georgia]

Many thanks, guys! I'm off to buy bleach. Am I right in assuming that if I go a bit overboard in the dosage - say 11 gal instead of 8.5 - that the only lasting consequence would be a small rise in salt level? I'd think that adding bleach in the evening might be a good idea, to avoid uv.

Here in Georgia, just south of Atlanta, we have a loooong pool season. 'Course our personal season will start a little late, but we should be splashing well after labor day.

Thanks again. I'll keep The Collective Mind posted.

[aylad]

By going overboard in the doseage, you're still okay and won't really notice an appreciable rise in your salt level. 11 gallons would take it up to 26-27 ppm. You just don't want to go too high in a vinyl pool and risk fading your liner.

Adding bleach in the evening is probably when you'll get the best bang for your buck, because it doesn't have to compete with the sun, but the key to clearing up the green is going to be consistency in keeping it above 20 ppm.

Janet

[George in Georgia]

Again, many thanks!

I'm going to hop over to the cleaning machines, where I can perhaps make a contribution on the Diagnostic Dolphin front.

[George in Georgia]

An update. Yesterday evening added about 11 gal of 6% bleach. This morning added another 8 or 9 gal., plus 32 oz 50% algaecide. At about 2pm added 9 gal bleach, plus some more algaecide.

pH is holding about 7.5. There is essentially no free chlorine present just before the next bleach addition. I suppose the algae is using it up. The pool does seem to be clearing a bit, I can see further down into the "lurking murk."

I guess we'll just keep on truckin', unless anyone has a better idea. I think we're getting a rep at Kroger and Publix as "those crazy bleach folks."

[Watermom]

Keep hitting it with bleach as you have been. The only algaecide we recommend is Polyquat 60%. A lot of the other algaecides will cause foaming or have copper in them which is something you do NOT want in your pool. Algaecides are pretty good preventatives but don't really help kill an existing algae bloom much.

[George in Georgia]

I hear and obey, O Great Ones!

The algaecide has no copper in it. I am an inverterate label reader. Is my guess about the reason that the Cl is so low correct, that its being "eaten" by the algae?

Again, many thanks to all for the advice and encouragement.