My new plaster pool is COVERED in green stain..

[mbar]

You have algae, and the only way to get rid of it is by using high levels of chlorine until the chlorine holds within 1ppm overnight. With a cya of 100 you need a minimum of 8ppms, and to take the pool up to shock levels you will have to take your chlorine level up to 25ppms and keep it there testing every couple of hours to get it back up to 25. You may also want to do a partial drain and refill to get your cya between 30 and 50. You are wasting money on all the chemicals the pool store is selling you to kill algae that will die with high levels of plain old bleach . I would be very leery of the chlorine tabs with specs in them. Make sure they don't contain copper. You also don't want to use the chlorine tabs that are trichlor as they will raise your cya even more. You should take a look at the chlorine forums and the algae forums - you will see that good old fashioned bleach really does work. The best suggestion I have for you is to get a good test kit so you can test your own water and learn how to take care of your pool yourself and not be at the mercy of pool stores. Do a lot of reading on this site, and ask any questions you have. Everyone here loves to help

[hausfrau]

You are so nice.

I have actually asked about a more high tech kit for testing my water and was told there isn't really anything better than the strips I am using. Hmm...a plot here? I do not want to be at the mercy of the pool stores...I am a nice calm person, but I am getting rather riled up as each time I go in, I get a different opinion.. Iwas wondering...should I have my well water tested-the water that the pool is hooked up to?

I will take your suggestion...and thank you for it. I am going to take a pool class that Self-Chem offers...but will take some of it with a grain of salt (no pun intended) as they probably want us to be dependent on their chemicals! I am also brushing the plaster more right now in hopes that it will inhibit the growth too. We are having lots of storms now (near Austin, TX) so I am sure this will throw everything out of wack too.

Please wish me luck! I'll keep ya'll posted on my pool nightmare!

[waterbear]

You are so nice.

I have actually asked about a more high tech kit for testing my water and was told there isn't really anything better than the strips I am using. Hmm...a plot here?

As someone who has worked in pool stores I can tell you that the answer is probably yes. We did not carry decent test kits (except for the K-2005 we stocked in units of 1 for the condo associations) so people would come to us for water testing and we could sell them a lot of stuff!
As far as test kits, get yourself a Taylor K-2006 (not the K-2005). It will save you a lot of time and money in the long haul!
You might have to order it online. Here is a link for Amazon:
http://www.poolforum.com/pf2/showthread.php?t=10006
While this is not the only place you can get it you will be supporting Pool Forum by ordering from this link and help keep it going.

[hausfrau]

Just for the heck of it, I had our well water tested to check on metal in the water. it came back very low for copper...0.2. So yes, algea. Now, to get a decent test kit (as suggested on this site) and buy some bleach...will keep ya'll posted!

[hausfrau]

Thanks for the good advice!

Muriatic acid seems to have done the trick in our spa. We turned the spa off and added a muriatic to the water. Let it sit for an hour. It really cleaned it up. The concentration would have been about .2% for total volume.

A few questions:

1. What is the maximum concentration of mutriatic acid that can be safely used in a plaster pool? (14400 gal)

2. Can the PH be lowered a significant amount for a period of time then raised to normal levels without potential damage to the plaster?

3. Should the DE in the filter be changed or backwashed to eliminate any residual algea?

4. As an aside, to eliminate the possibility of metal staining, will muriatic acid also remove Cu or other metals from the surface of the pool?

Again thanks for the help. Big learning curve for us on this!

[hausfrau]

Did all of that. Honestly, we have tried it all. Still there...a little worse. Is it possible that minerals or something is leaching from the gunite that can cause stains which are almost impossible to remove? The pool's gunite cured during heavy pollen season. The pool is under trees. If the plaster folks did not wash out all of the pollen properly..could this be causing a problem?

[waterbear]

first lets get down to basics....
How are you testing your water?

If, as you say you have "Honestly, we have tried it all." and it is "Still there...a little worse." THEN
I can honestly say that you are trying to adjust your chemicals with imprecise test results or you are just "dumping and guessing". Which is it?

Killing algae is easy if you know the CYA. Raise the FC to the proper level as in this chart
http://www.poolforum.com/pf2/showpos...50&postcount=1
You need to maintain the FC at the proper shock level or a bit above by testing the FC and adding more UNSTABILIZED chlorine at least twice a day and more often if possible. The more constant you keep the FC at shock level the faster you can kill the algae. You keep the FC constant by testing and adding more chlorine to bring it back up to shock level. Run the pump 24/7 and brush the pool to break up any biofilms. You really can't overbrush but use a nylon brush on new plaster.
IF you do this you will get rid of the green very quickly. I have seen pools go from swamp to cloudy in 24 hours and then a few more days for the filter to clear the dead algae many times.

Without GOOD test results you have no idea of HOW MUCH and HOW OFTEN of WHICH chemicals you need. Pool store testing is well and good in some cases but you really can't go running there two or three times a day to get your water tested.

How much did your new pool cost? Now, is around $50-$80 a lot to spend on the one tool that will keep your pool in top shape and save you a lot of money in the long run, not just on chemicals but on protecting the plaster and getting the maximum life out of it? I think not. Get yourself a good test kit! Best bang for the buck is the Taylor K-2006 (not the K-2005).

Algae is very easy to kill but we really need to know current water parameters and NOT from strips. They are just too unreliable, particularly with CYA, CH, and pH.
To kill algae and keep it away we need to start with an accurate and precise CYA reading and need to know exactly which form of chlorine you are using if you are not using bleach or liquid chlorine because it can make a difference.

Hope this helps.

[waterbear]

Did all of that. Honestly, we have tried it all. Still there...a little worse. Is it possible that minerals or something is leaching from the gunite that can cause stains which are almost impossible to remove? The pool's gunite cured during heavy pollen season. The pool is under trees. If the plaster folks did not wash out all of the pollen properly..could this be causing a problem?

In a word, no.
Pollen floats on the surface and does not stain under the water. It can deplete chlorine and allow algae to grow. Your description of the problem and how it occurred and the things you have done to treat it leave no doubt in my mind that you are dealing with algae and just not doing what you need to do to get rid of it. First step is a good, current CYA reading.