High phosphates and chlorine loss.

[Piperca]

I am finding that my pool is dropping approximately 2ppm chlorine overnight (6.0 to 3.8) I know my phosphates are high in the 1500 range and I see a little green algae along one wall of the pool (shaded side) when I brush the pool at the end of the week. How should I approach this issue? Phosphate remover or slam?

 

[mknauss]

Follow the SLAM Process

If you wish to deal with phosphates, the pool needs to be algae free prior to that. Also be sure you are testing your own phosphate levels. If high (typically in excess of 2000 ppb), then use Orenda 10000.

Phosphate Removers - Further Reading

www.troublefreepool.com

 

[Piperca]

So, would treating the pool with an algaecide then using a phosphate remover be an acceptable approach? I’m a new pool owner (2 years) and have never dealt with this issue before. Based on what I’ve read on the forum and from advice from members, I have ignored the phosphate level and slowly watched it climb. I’m not sure that was the correct approach, was it? I’m not confident in carrying out the slam procedure, since I’ve never done it before. It appears it needs constant vigil and testing, which might be difficult with my weekly schedule.

 

[mknauss]

Algaecide is designed to prevent algae in under chlorinated pool water. It does not kill algae.

Phosphates are immaterial if pool water is properly chlorinated.

SLAM does take some effort. You can do it quickly if you drain the pool completely and start with fresh water.

 

[Bperry]

So, would treating the pool with an algaecide then using a phosphate remover be an acceptable approach? I’m a new pool owner (2 years) and have never dealt with this issue before. Based on what I’ve read on the forum and from advice from members, I have ignored the phosphate level and slowly watched it climb. I’m not sure that was the correct approach, was it? I’m not confident in carrying out the slam procedure, since I’ve never done it before. It appears it needs constant vigil and testing, which might be difficult with my weekly schedule.

It’s not hard, just raise the water to SLAM level and do your best to keep it there. The only reason algae is there is because you don’t have enough chlorine in the water so get some in there ASAP.

 

[Piperca]

Okay, slam it is. Unfortunately, I just raised my CYA to 80 a few weeks ago. I guess I need to lower it with a partial water change. How would I calculate how much water to change?

 

[mknauss]

If you wish to target 40 ppm CYA, that is a 50% drain/ refill. I do not know your water cost, so balance that against the higher FC level you need with your current CYA.

You need to be sure your SWCG is generating enough chlorine for your pool going forward.

 

[Bperry]

Okay, slam it is. Unfortunately, I just raised my CYA to 80 a few weeks ago. I guess I need to lower it with a partial water change. How would I calculate how much water to change?

I’d just keep the water and dose it to the higher SLAM level of chlorine

 

[Piperca]

I ordered a phosphate test kit and a supply of CYA reagent for my Taylor K-2006 kit, so I can properly test the levels. I did run out to Leslie’s a few minutes ago and had the water tested. I know, not ideal, but I was curious. Their FC was close to my test (3.8) at 4.16, with a CC of 4.62. CYA was at 67, which is lower than I anticipate. I have not checked it since adding conditioner. Phosphates were at 1691, which is consistent with prior readings over the past year. The TA reading was lower than the 90 I got this morning. They got a reading of 68, based on an offset from the CYA level. I read a little about it before posting and found that this practice is questioned throughout the pool industry, so I’m not concerned.

I have my grandkids until Friday, so I’ll begin the slam on Saturday.

Thanks to all who have shared their insight, I truly appreciate it. I’ll update you all on the outcome.

 

[mknauss]

In the interim, raise your SWCG generation to 5+ ppm per day.

 

[Piperca]

I’m not sure how to do that. It is running at 80% right now and has been for a couple of months.

 

[mknauss]

Use PoolMath
Effects of Adding Chemical
How many hours a day do you run the pump?

 

[Piperca]

I run the pump for 8 hours at 2450 rpm.

 

[mknauss]

That is adding 3.3 ppm FC to your pool.

If you increase the pump run time to 12 hours, that would be 5 ppm.

You likely can reduce your pump rpm.

 

[Piperca]

Okay, thank you. I’ll up the run time.

 

[Piperca]

Quick question: I intend on beginning the SLAM process in the next day or so. It’s about time for a filter cleaning. Should I wait until after the SLAM or do it before?

Also, I got my phosphate kit and tested; between 1000 and 2000 was the result. CYA is 60. Looks like I need to maintain a chlorine level of 24 … wow, seems like a lot of chlorine! What’s the best way to add this much? (2 gallons +)

 

[mknauss]

What’s the best way to add this much? (2 gallons +)

Pour in the pool at a return with pump running.

 

[IceShadow]

Quick question: I intend on beginning the SLAM process in the next day or so. It’s about time for a filter cleaning. Should I wait until after the SLAM or do it before?

Also, I got my phosphate kit and tested; between 1000 and 2000 was the result. CYA is 60. Looks like I need to maintain a chlorine level of 24 … wow, seems like a lot of chlorine! What’s the best way to add this much? (2 gallons +)

Keep an eye on the pressure. When it’s 25% above clean, clean the filter. If your pool is mostly clear and you are doing this due to seeing some algae, the filter may not get much more on it. It’s the cloudy pools that need lots of filtering.

Be sure you check hidden areas for algae when brushing the pool during the SLAM. Light niches, weir doors and skimmer throats, inside ladders, main drains, all areas known to house algae.

 

[Piperca]

Success! It was a bit of a struggle with the heat and the SoCal fires, but the chlorine has been consistent at 11ppm for the last couple of days. Now I need to drop the chlorine level and add the correct amount of conditioner for the long run. Any suggestions on the perfect combination? The conditioner is about 40 at the moment.

I‘ve also noticed the alkalinity is more stable. It’s staying lower for longer. Why is this happening? Has it anything to do with the higher chlorine level?

 

[mgtfp]

I‘ve also noticed the alkalinity is more stable. It’s staying lower for longer. Why is this happening? Has it anything to do with the higher chlorine level?

What's the TA of your fill water? It could be a coincidence with having to add less frequently fill water to replace evaporated water with summer turning into autumn.