I can't get rid of CYA

[domct203]

Well... now I am very confused. Should I do something about the pH?

While the pH is high, you have bigger issues to resolve first as you may be draining that pool.

Lets take a step back a bit......

How did you normally sanitize the pool? Is the pool a bromine pool, or a chlorine pool?

If it is a chlorine pool, you should have never added the bromine...... Whoever gave you that advise just caused you quite the headache. How much bromine was added?

If you have a bromine pool, you need to let us know so we don't make matters worse.

The following great advise was already given, but this is for a chlorine pool.

Welcome to TFP!!!

You have been given the "best advice" multiple times.

1. You MUST invest in one of the recommended test kits and stop trusting the pool store testing. (Done!)
2. You then replace water to get the CYA to a reasonable level (Could be lower, but at 70ppm is better)
3. You follow the SLAM process to eradicate the algae: SLAM Process (No mention of bromine)
4. Maintain adequate FC levels which are a function of your CYA levels (see [FC/CYA][/FC/CYA]) and you will never have algae again. (in a chlorine pool)

 

[pooldv]

Well... now I am very confused. Should I do something about the pH?

It is important to maintain PH between 7.2 and 7.8 at all times.

 

[olboucha]

Thank you all for your comments. I wanted to make a correction: what I added to my pool water was sodium bromide 88.8% (yellow treat). My pool right now looks OK, other than some color and brown algae at the bottom. How can I keep the recommended FC in the pool?

 

[domct203]

Thank you all for your comments. I wanted to make a correction: what I added to my pool water was sodium bromide 88.8% (yellow treat). My pool right now looks OK, other than some color and brown algae at the bottom. How can I keep the recommended FC in the pool?

Yellow Treat is a bromine salt (sodium bromide) that will convert your chlorine pool into a bromine pool.

Did you only add the recommended dose of 5oz per 10,000 gallons?

You will now have to fight the bromine to make the pool a chlorine pool once again, but as you are seeing, it will take a lot of chlorine over many days to do so.

It takes 37oz of 8.25% laundry bleach to add 1ppm FC to your 25K gallon pool. A 96oz jug of bleach only adds 2.5ppm to your pool.

We need to try to get your pool to a shock level of 28ppm FC for a CYA of 70ppm. That will take over 11 jugs of bleach if your current FC is 0ppm.

If you exchange some more water first to lower your CYA more it will make this process much, much easier. Two 25% drain/refills would really help.

Could you please post a complete set of recent test results before you do anything else?

 

[olboucha]

PH-8.2
CL- 5 ppm
FC- 9
CC- 0.5
CH- 550
TA- 170
CYA- 60

 

[tim5055]

PH-8.2
CL- 5 ppm
FC- 9
CC- 0.5
CH- 550
TA- 170
CYA- 60

Time to step back here and take a deep breath. You really need to slow down, and listen to the questions being asked and answer them.

Dom is clearly trying ot work with you, but he needs to know - how much bromine salt (sodium bromide) did you add to the pool? It's human nature to think if 5oz is good, then 20oz must be better, so if you added more than the directions said please let us know. The advice for 10oz of yellow out is probably much different then a whole bottle.

Just off the top of my head I'm going to say you need to do a large water exchange, both to get that CYA into a reasonable range to SLAM Process the pool and to reduce the effects of the bromine salt you added.

 

[olboucha]

Thanks to Dom and everyone else who is been trying to help me. I added the whole bottle in two separate times; (Approximate 16 oz each time). Before that I emptied my pool about halfway and refiled with fresh water. At this point I cannot afford to empty it again, this is a big pool. Yes, I am listening to the questions and to the advices given, but please keep in mind that I am not an expert on pools and am even less familiar with pool products. My question is: Is water exchange the only way to solve my algae problem?

Thanks again.

 

[tim5055]

The only way to solve your algae problem is to get sufficient sanitizer in the water and keep it at a sufficiently high level (hence the [FC/CYA][/FC/CYA] we use) for a long enough period to eradicate the algae.

At this point our normal methods and calculations won't work because of the addition of a variable - bromine salt in the water.

One solution would be to drain/refill the pool so that we eliminate the bromine salt as well as get CYA down even further. You indicate that this is not an option due to the cost involved.

Another solution will be an attempt at a SLAM Process, but I'm not even sure how you would go about calculating the additions of chlorine with the bromine in the water. I'm not sure it's even possible.

I will gladly yield to one of our chemists to provide some guidance.

 

[JoyfulNoise]

Ok, so 32oz of the Yellow treat (88% sodium bromide) is going to roughly add 8ppm bromide to your water. This is going to consume some chlorine as chlorine oxidizes bromide back into bromine and the chlorine is reduced to chloride. Bromine unfortunately is a poor pool sanitizer because it is highly susceptible to UV photolysis which converts the active bromine sanitizer back into bromide. Unfortunately bromine can not be stabilized like chlorine can so this swimming pool is always going to have a high apparent chlorine demand. In other words, it's going to use up sanitizer faster than a pool with no bromine in it.

You can still SLAM the pool but it's going to appear as though your chlorine is being used up faster than you would expect. You'll still follow the same SLAM procedure and exit criteria.

The FAS-DPD test measures total "halogen" concentration so, in your case chlorine + bromine, there is no way to distinguish between the two. When SLAM'ing you can still use the same shock level (40% CYA) but just know that you are going to have to add chlorine more frequently.

The real problem for you is going to be when the pool is free algae, the bromine will still be there. So when you try to return to normal pool sanitizer management, you're going to find it difficult to maintain a consistent sanitizer level because the bromine is going to consume chlorine rapidly and will, itself, be used up very quickly by UV.

At some point you're going to have to bite the bullet and drain water as that is the only way to reduce bromine levels.

 

[domct203]

As Matt has mentioned, sooner or later you will need to replace water to reduce bromine. If you do that now it will make the entire process easier as it will also lower CYA & resulting shock FC level, helping with the SLAM. If your CYA is 60ppm, consider draining 50%.

 

[olboucha]

OK, thank you all. I'll try to drain it as much as possible.