Algae AGAIN....

[dmmcintyre]

20,000 gallon in-ground vinyl pool
Hayward 1hp, sand filter
Auto chlorinator which holds 10 tablets
We run the filter from 6:30 am - 7:00 pm DAILY

I have read your sticky, "Turning Your Green Swamp Back into a Sparkling Oasis".

I'll give some background first. We had algae and fought it for a little over a month. We finally made some corrections to the pump system, like replacing a seal which made the pump work better, then we replace the sand in our Hayward. Once these 2 things were done, we shocked the heck out of the pool and also added Green Treat. We ran the pump 24/7 till the algae was all dead. We added Flocc, ran the pump on re-circulate for 2 hours and shut it off till the next morning. We vacuumed to waste a couple of times and backwashed. BAMMMMM....Crystal clear water, FINALLY. It stayed like this for about 2-3 weeks. It was wonderful. We took a sample in to our local pool store and was told the stabilizer was getting low. Back to the grocery store we went for panty hose. We added the chemical to the pany hose and milked, and milked. But the water stayed crystal clear. :-D

This past weekend, we swam for 2 days straight with friends in about 85-87 degree weather (southeast Texas) and the water being about 80ish. This is what our weather has been for several weeks. We needed to add some water this past Sunday so we did, then it poured Monday. NOW I have algae again.

We took a sample into our local pool store and the readings were as follows:

Free Chlorine: OVR 10. ppm
Total Chlorine: OVR 10. ppm
Combined Chlorine: 0.0 ppm
pH: 7.4
Hardness: 160 ppm
Alkalinity: 40 ppm
Cyanuric Acid: 70 ppm
Copper: 0 ppm
Iron: 0 ppm
Total Dissolved Solids: Not Run

We were told to scrub pool, and sprinkle the Green Treat and run filter 24/7 and then sweep to waste then backwash

OK, here is my question. Why is my pool getting algae when my chlorine is OFF the charts?

Dina

 

[duraleigh]

Hey, Dina,

Welcome to the forum. You'll get lot's of great help here.

OK, here is my question. Why is my pool getting algae when my chlorine is OFF the charts?

There are several possibilities but let me say that algae will not grow in a properly chlorinated pool. So, here's a couple of thoughts....

1. Testing error (Probably not but the possibility is there)

2. Uneven application of chlorine.....this is a real possibility. Have you ever allowed your FC to dip below 4ppm? Even though your current level appears fine, you must constantly replenish chlorine in your pool as it is consumed by the sun and organics.

 

[JohnT]

Welcome to TFP!

Your chlorine isn't off the chart for a real test kit. You can't rely on a pool store for testing, especially one that doesn't test the water any better than yours. Pool stores are very often dramatically wrong with their results, and you need to test the water daily or more often. You also need to know what your chlorine levels are. Your pool needs 28ppm to shock, so only knowing that it's over 10 tells you very little. You can raise the chlorine level to 30ppm during an algae bloom, and the chlorine can be down to 0 in just a few hours. You'll be testing 5 or 6 times a day when fighting algae.

Chlorine varies regularly during the day due to sunlight, bather load and pump run times. At a CYA of 70, 10ppm is only slightly above the recommended level for normal chlorination. It won't kill algae once it gets started. Having friends over and swimming adds quite a load to the pool, and the chlorine went down as it neutralized the biologicals added by swimmers. While it was down, the algae got started and now 10ppm is not enough to stop it.

Get a kit. Nothing will do what you need but the Taylor K2006 or it's private label versions, or the one at TFTestkits.net. Once you understand what's going on in the pool, you can treat the problems as soon as they start instead of reacting when it's too late.

 

[dmmcintyre]

I'm really starting to think that our local pool supply company are complete idiots. I really appreciate all you advice. I have learned A LOT from this website. I will take the advice and SHOCK the pool this afternoon. I have also ordered the test kit recommended.....

Thanks Again,
Dina

 

[duraleigh]

Dina,

1. With your CYA that high, you can shock up to 30ppm without harm. The trick to clearing up your pool is you must hold it there until your pool clears....may take a few days and it'll sure take quite a bit of chlorine.

2. Your CYA is already just a little too high. The pucks are the culprit and you will need to work on a solution. more on that later.

3. Your kit will ship this afternoon and I think it's 3-4 days to Texas so you'll probably have it Saturday (thanks for your business). Please post your own test results as soon as you get the kit and you will get a ton of good help from many very knowledgeable people on the forum.

 

[dmmcintyre]

In reading the sticky, it stated that the chlorine level needs to be 28-30ppm (shock the heck out of it). On my lunch I stopped by the local pool supply store and purchased a 5 gallon of shock. I asked the girl in the store that has been helping us (ROFLMA) and I said, "what level does the chlorine need to be to kill algae"? And she stated, are you ready????? ABOVE A 3 !!!! And I asked, "in ppm's" and she said, "yes"......

I really wanted to go home and drink, but my husband and I dumped all 5 lbs in a bucket with water, dissolved it and put in the pool.....

Does shocking the pool lower or raise the CYA?

Duraleigh, you stated that my CYA is high, but it was read at 70ppm (OH, Crud...the pool supply store told me that). Remember we just "milked the pany hose" for several days last week.

 

[JohnT]

Does shocking the pool lower or raise the CYA?

Duraleigh, you stated that my CYA is high, but it was read at 70ppm (OH, Crud...the pool supply store told me that). Remember we just "milked the pany hose" for several days last week.

It depends on the product you use to shock. Trichlor and Dichlor raise the CYA. Sodium Hypochlorite (Liquid Shock or Bleach) and Calcium Hypochlorite don't affect the CYA. Draining and replacing water is the only reasonable way to lower CYA. 70ppm is liveable, but 40 or so is better.

 

[dmmcintyre]

I remember looking at the shock bottle and it was Calcium Hypochlorite . I guess I could stop guessing and wait for my neefty kit you are sending me.

 

[mdhwoods]

I remember looking at the shock bottle and it was Calcium Hypochlorite . I guess I could stop guessing and wait for my neefty kit you are sending me.

Calcium Hypo raises calcium and chlorine not cya.

 

[Butterfly]

In reading the sticky, it stated that the chlorine level needs to be 28-30ppm (shock the **** out of it). On my lunch I stopped by the local pool supply store and purchased a 5 gallon of shock. I asked the girl in the store that has been helping us (ROFLMA) and I said, "what level does the chlorine need to be to kill algae"? And she stated, are you ready????? ABOVE A 3 !!!! And I asked, "in ppm's" and she said, "yes"......

She probably didn't even realize that the cash register was going cha-ching, cha-ching, cha-ching :lol:! Thankfully, you were armed with knowledge!

I really wanted to go home and drink, but my husband and I dumped all 5 lbs in a bucket with water, dissolved it and put in the pool.....haha! we need some more emoticons!!!

You have come a long way in a short while Congrats on not being pool stored!

Are you still using the pucks? If yes, then please stop and only use liquid chlorine/bleach for shocking the pool and for maintenance. You could probably skid by w/your kinda high CYA of 70. If you stop using the pucks, it will come down on its own over time.

Congrats on ordering the TF100 Test kit. This will put YOU in control of your pool :lol:

Welcome to the forum

 

[dmmcintyre]

First Test with NEW Kit (TF-100)...Let me know

05/16/09

FC = 7
CC = 0
TC = 7
pH = 7.2
T/A = 90
CH = 300
CYA = 95

20k gal
vinyl
Hayward Super Pump, Sand, auto chlorinator

All right yall, give it to me.

 

[Guest]

Other than the too high CYA and the too low chlorine for that CYA level your numbers are good. My suggestion is to do a series of partial drains and refills (usually a foot below the skimmer is safe for just about anyone) and get the CYA down to a more managable level. I would shoot for below 70 ppm and take it from there. Remember to retest the chlorine and adjust it up to the appropriate level if needed after each refill so you don't get any (more ) algae.

 

[dmmcintyre]

I filled the pool about 1 1/2 inches last night so I could sweep to waste the dead algae that I missed. So this kinda works because I will have to fill back up when I'm done. After reading this site, I KNEW the CYA was high and needed to lower it.

Question: I realize there are a couple of diff types of algae and we have been killing green algae. But someone brought it to my attention that maybe the algae is yellow. I thought, ummmm. But wait, it looks green. He informed me that my liner is BLUE. Now I have to revert back to kindergarten and think. BLUE liner and YELLOW algae makes GREEN.....Holly Crud, now what????

 

[JohnT]

Mustard algae is more of a middle of the summer problem, and it looks yellow/brown even on a blue pool.

 

[chem geek]

Also, yellow/mustard algae tends to grow on the shady side of the pool and is dust-like whereas green algae is usually more free-floating and "heavier" (i.e. not like dust).