Pool Algae Problem Support - READ FIRST

[chem geek]

perplexed,

You didn't say what your specific Free Chlorine (FC) and Cyanuric Acid (CYA) levels were. Many pool stores will 1) incorrectly measure CYA and 2) consider 100-200 ppm CYA just fine when it isn't. Please post your actual measured numbers and do yourself a favor and get your own good test kit such as the Taylor K-2006 you can get at a good online price here or the TF100 from tftestkits.net here with the latter kit having 36% more volume of reagents so is somewhat comparably priced per test.

If the green is algae, then even with high phosphates you should be able to kill it faster with chlorine than it can grow IF you maintain a sufficient FC/CYA ratio. I suspect that your FC is below 7.5% (maybe even below 5%) of the CYA level.

[ScosheOwn]

ChemGeek, thanks for all the great info about keeping chlorine at 7.5% of CYA, how certain types of chlorine raise CYA and calcium hardness, etc. You say that you just add enough chlorine each day to amke up for loss, keeping the level right around 3-5PPM. But don't you have to also periodically shock (raise chlorine to above 10 ppm) to 'burn off' the combined chlorine? Or is that just a myth?

[chem geek]

If you properly maintain the appropriate FC for the CYA level then you do not need to shock regularly. You only need to shock if there is an unusual event such as unusually high bather load or a fecal accident or dead animal, etc. I have hardly ever had to shock my pool and the same is true for tens of thousands of members on multiple pool forums who follow the methods described in the Pool School.

[Peggy]

I have small black spots on the side and bottem of my pool. They are like little dots. I can scrape off
the tops with my nail. I am guessing this is algae, never had this before. It is a plaster pool size
20 by 40. We have all chems blanced and the pool is clear. It is hot here in Texas and the water temp.
is 90 degrees. HELP.
Peggy

[chem geek]

This sounds like it could be black algae. This only develops if the pool has had too low a Free Chlorine (FC) level relative to the Cyanuric Acid (CYA) level for an extended period of time. Read the Pool School link I gave in the previous post including the article there on Defeating Algae. Note that for Black Algae you not only shock the pool, but need to regularly brush the algae to knock off the heads as you are doing to expose the deeper algae to high chlorine levels to kill it.

You should get yourself your own good test kit, the Taylor K-2006 here or the TF-100 here.

[pooltec]

Have an algae problem in the pool? Check this out! This is the lastest product from Aquatron called Cobia.

It cleans, scrubs, and as well as sanitizes your pool at the same time. You can practically sleep for a month and come back later to find out that your pool is still sparkling blue. Zero maintainance!

Chlorine On Board Integrated Automation (C.O.B.I.A.)

C.O.B.I.A. system uses a compact electrolytic cell to produce chlorine on-site, from sodium chloride (salt) present in the pool. This process of pool chlorination occurs as pool water passes between a series of titanium plates which make up the cell. These plates have low current passing between them causing an electro-chemical reaction leading to the production of chlorine.

How does the Cobia system work? Turn on the power supply and the robot will begin to clean and chlorinate the pool. Each day, this robot will work on its own without touching any buttons. The multi-function user interface is located on the power supply which displays the chlorination time and lets the user know the system status. The interface alerts the user when salt levels are too high or low. The interface has two separate LED�s indicating when the system is in cleaning and/or chlorinating mode(s).



Features

•H2O + Salt + COBIA = sparkling clear pool with naturally chlorinated water
•Totally independent from the pool filter or pressure line
•No hoses or connections
•Reduces energy and chemical costs by approximately 50 percent
•Easy to remove 2 micron filter bag collects sand, silt, or leaves
•Saves energy costs reducing use of pump and filter
•Lightweight and easy to maneuver
•Keeps pool water softer, cleaner, and fully sanitized all at the touch of a button
•Operates on a low salt level (3,000 ppm) which is less than a human tear
•No more storing and transporting extra sanitizing chemicals
•No more damaged hair, red eyes, irritated skin, and color faded bathing suits
•Pool size: Up to 40,000 gallons
•Input power: 115/230 VAC, 50-60 Hz
•Total output power: 12-32 VDC, 198 Watts
•Chlorine: 16 grams per hour
•Expected cell life: 5,000 hours
•2 year / 300 cycles manufacturer warranty
•Chlorinator: 2 year / 8,000 hours manufacturer warranty

[floridapooltech]

@ Pooltec:

I don't believe this system is what the average consumer is looking for for many reasons (read on):

1. Pool owners want something that will make pool maintenance easier. A MOUNTED salt system with a separate automatic pool cleaner both linked to the timer is EASIER. A pool cleaner with a built in salt system that you manually have to control is not.

2. A salt system that lasts 10,000 hours with a 3 year warranty for less than $800 with a pool cleaner for $300 with a 2 year warranty that operates all by itself without human assistance is much better than an $1800 system that you have to manually operate...(oh, and the COBIA has half the life expectancy might I add)

3. When a salt cell goes bad on a salt chlorinator, all you have to do is unscrew 2 unions, then swap them out. The same goes for cleaning it. What happens when you need to service or replace parts on this huge machine??? Still haven't convinced me of it's effectiveness yet.

4. This forum post was regarding an algae problem. I don't think anyone in this post asked for an advertisement of a pool cleaner with an onboard salt disaster. Please keep this forum to a "help-only". We run a store yet we still don't go advertising all over the place! Help the pool owners out, that is what they're here for.

[loveaz]

3. When a salt cell goes bad on a salt chlorinator, all you have to do is unscrew 2 unions, then swap them out. The same goes for cleaning it. What happens when you need to service or replace parts on this huge machine??? Still haven't convinced me of it's effectiveness yet.

I do not get this.. All you have to do is swap out 2 unions?

[floridapooltech]

3. When a salt cell goes bad on a salt chlorinator, all you have to do is unscrew 2 unions, then swap them out. The same goes for cleaning it. What happens when you need to service or replace parts on this huge machine??? Still haven't convinced me of it's effectiveness yet.

I do not get this.. All you have to do is swap out 2 unions?

No, there should be two union nuts (one on each side of the cell). When you remove the old cell, a new cell will fit in the existing space.

[Renee]

Hi last year I bought a house and found out that they left the swimming pool green. It was in late June after a freezing winter that we discovered the problem. I was able to remove it but it came back periodically so in august I decided to not to anything to it until this year. So I closed in late October the way they said to me at the store. I want to replace the sand. Do I need to wash the incide walls of the filter? If yes with what and if I already changed the sand, what can I do?

[COSTAS]

I have a pool and become green and cloudy . When i checked the level of chlorine i find out that the chlorine disapire sudenly from the water. I add a lot of chlorine but no changment.the level of ph was a little high. The next day i add acid because i beleive was i lot of free chlorine in the water ( the tester show high chlorine) but nothing change.now i have a swimming pool with green and cloudy water and the tester show too much chlorine and too much acid.
The same proplem i had also last year the same time.few days sun shine and start this problem.
I wondering as around the pool there are a lot of tree and flowers if any of these trees give problem to the water as now start the spring .
I dont know what to do.add more chlorine(superchlorination) add more acid as i done once in a swimming pool with same problems ( within 24 hours the water become crystal) or i add soda ash for incrwase the ph.
Note that is a big pool arround 200,ooo litres water and i add since now 50 kg acid and 10 kg chlorine

thank in advance
best regards
costas ioannou ( cyprus)

[chem geek]

Do you know the Cyanuric Acid (CYA aka stabilizer or conditioner) level in the pool?

If it's a cloudy green, it's likely to be algae (a clear green would be more likely to be metals). Chlorine will kill the algae, but if the CYA level is too high then it will take an extraordinarily high FC level to do so. Lowering the CYA level would be the best long-term solution since you'd have to do that at some point anyway.

[Swimsim]

Hi Larry,

Righto here goes...
I have a above ground Intex pool, left water in over the winter, teenage sons who think they know best half emptied the pool in March then refilled it and plopped a tub of our usual floating chlorine and surprise surprise the algae stayed in the pool!!!!

Now I have tried my best to get rid of the algae - wont bore you with the details as reading the forums I have wasted my pennies and did it all wrong!!!

Have now empited the pool, all bits & pool have been cleaned (by me this time) and I have about 5 " of water left in the bottom with some algae still laying loose - question is what do I do now???
1. Refill & plop our floating chlorine in & that will get rid of the algae (as there isn't alot) ??
2. Put some 'shock treatment' in the remaining water ??
3. Fill up pool & put some shock treatment in the pool ??

All advise will be most welcomed as the weather has alast turned nice & summer like.

Thankyou

[chem geek]

Physically remove whatever algae you can since that will make things easier. Then, fill up the pool. You can add some chlorine to it as it is filling up. Easiest chlorine to use to start with would be Dichlor since it dissolves quickly and adds both chlorine and CYA, but you don't want to use too much. You would then use chlorinating liquid or bleach to shock the pool to a higher chlorine level -- around 40% of the CYA level. That should kill off the algae. Read Defeating Algae.

[Kurt H]

Problem: Trying salt for first time. Pool has been set up for only 2 weeks. Just noticed green water and significant visual algae today, but has probably been growing for 3-4 days. I do not have a chlorinator - is there another method of chlorinating? Can I simply add chlorine (bleach) to salt water? I Will check pH and FC levels before chlorinating.

FC:
TC:
pH:
TA:
CH:
CYA:

My pool: Intex 18' dia. x 48" deep
Pool chemicals: 160 lbs. salt
My pump & filter: Intex with size A filter
Other info: