CMP Powerclean Ultra low output

[Poolmonkie]

this is my second summer running my CMP powerclean ultra SWG and in the past I would run it at 25% and it would stay about 3-5ppm, 50% or higher and it would be 7ppm higher even in the middle of the summer heat in Arizona. In the past week as the temps have come up (pool temp about 74 max during the day and air temps mid 90's) I"m barely getting 2ppm after the unit has run for 8 hours at 100%. I am going to do an overnight chlorine loss test but I have never had algae in the pool and have kept it very clean and the swimmer load is one person. I have cleaned the cell itself when there was actual buildup but for the most part there really wasn't much at all and I only used the plastic stick that the manufacturer provided, I never used acid.

The CYA is at 30 and I know it should be raised a bit but I'm testing first thing in the morning after the pump shuts off and before there is any sunlight on the pool. Salt level was measured at 4500 by two differen't meters and CMP recommended range for this cell is 4000-4500. I did do a Chlorine check at the return when the pump is running high speed and it was 5ppm at 100%.

Any ideas on if this is a sign that the cell is failing? The unit hasn't been in operation 2 years quite yet.

 

[YippeeSkippy]

Oh yeah..... your climate almost demands more sun protection via higher CYA. Try upping the CYA to 40 and see if that helps. Most folks your way go up to 50ppm CYA even.

I'm not familiar with CMP Powerclean ultra SWG.... what size pool is it geared for?

Maddie

 

[Poolmonkie]

For sure I'll slowly increase my CYA back up to 40 or 50 for the summer, that is where it normally is but it slipped during the winter. But I am measuring the chlorine immediatley after it has run through the night and before the sun has risen much above the horizon let alone shined on the pool water.

As for the cell it's rated for a 40,000 gal pool and produces 1.35lbs of chrlorine per day.

 

[TheRaven]

I have the exact same unit and i'm running it at 50% for 10hours/day. My pool is about 19k gallons. I target 5ppm FC and it's just about stable there, gaining about 0.5ppm weekly. My CYA is at 30ppm but i'm in a very different climate than you.

I know guys who have had the same cell for 8-10 years with no problems so it would seem you have some kind of issue going on with yours.

 

[mknauss]

Your target in Phoenix should be at least 70 and even better 80 ppm with a SWCG. You will see a significant drop in FC loss per day. If you leave your CYA at 50 ppm, a 5-6 ppm FC loss per day should be expected.

 

[Poolmonkie]

I'm adding CYA right now and will bring it up to 70 slowly this week and continue to monitor the FC. I'm running the SWG 8 hours a day at 100% right now. This morning I took a FC reading just before the sun hit the pool and right after the SWG finished it's 8 hour cycle and it is about 4.5 so I'm hoping that trend continues and the increased CYA will protect more as it increases. Thanks for the info and I certainly would love if this unit gives me 8 to 10 years though I know that can vary a lot.

Another question, during the winters here since pool water can get down into the 40's with no freeze... should I take the cell out and store it inside?

 

[Poolmonkie]

Update:

Well the past couple of weeks I've been running the SWG 100% for 8 hours a night and every morning just as the sun is coming up and the SWG is turned off I'm at 4.5 or 5.0 FC. By the end of the day after full sun and with a water temp of 77 I show a FC level of 3.0 I did increase the CYA to 50 and will move to increase it 60 this week. Arizona is coming up to the peak heat and sun in the next couple of months and I can sometimes see water temps pushing 88 degrees by August. I am concerned that the Chlorine output won't keep up and last summer I did notice small amounts of algae on the walls and did add a floater with a couple of pucks during the worst of the heat.

Obviously the SWG is putting out chlorine, the question is will it be enough in the next two months. Would my only choice be to increase the run time on the SWG another hour or two?

 

[mknauss]

In our climate, you need a CYA level of at least 70, even 80, to retain the FC levels using a SWCG.

 

[Poolmonkie]

Ok, at what CYA level will the Chlorine no longer be effective? I'm a bit hesitant to push it too high too fast and end up having to do a water exchange if possible. Also, If I'm seeing 5.0 in the morning and by evening it's down to 3.0, is that acceptable as far as loss for daytime?

 

[mknauss]

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