Could reduced pipe diameter or the new heater be the problem?

[kenlip]

I have an above-ground vinyl pool with a sand filter. All the plumbing was 40mm/ 1.5”.

I have recently replaced the liner. The water looked great for many weeks. A few weeks ago I added a heater (Bestway) to the system.

The inlet and outlet to the heater are 25mm/1”. The opening on the ball inlet to the pool is 22mm.

With these dimensions in mind, and because I don’t have many options for the position of the heater, I decided to deviate the water in the return pipe through 25mm flexible irrigation pipe (blue-line).

Over the next few weeks, the water has deteriorated a bit. It has become a little bit cloudy and there is possibly a little bit of algal growth on the floor (none apparent on the walls).

Using the TF-Pro kit, my readings are:
pH 7.2
Combined Chlorine 0
Free Chlorine has been kept around 7 for a few days to see if that would help
Alkalinity 30
CYA 40
Hardness 0

My understanding is that those are pretty good numbers so the chemistry seems okay to me.

This got me wondering if the reduced diameter of the piping in the return plumbing is reducing the flow through the filter which is causing/contributing to the cloudiness. The other variable I thought could be responsible is the increased water temperature since we started heating the water.

Cheers, from sunny Sydney.

Ken

 

[ajw22]

This got me wondering if the reduced diameter of the piping in the return plumbing is reducing the flow through the filter which is causing/contributing to the cloudiness.

I doubt it.

Do a Overnight Chlorine Loss Test and if you fail then follow the SLAM Process

 

[Newdude]

Free Chlorine has been kept around 7 for a few days

You are losing up to 4 FC per day just barely over your peak UV month (January). Was 7 the target after dosing or the low when you tested ?

 

[kenlip]

You are losing up to 4 FC per day just barely over your peak UV month (January). Was 7 the target after dosing or the low when you tested ?

FC=7 was when I tested (mid morning). I decided to add a lot of chlorine to see if it would help at all. I know - that's hardly a scientific approach to chemistry. I added 2 litres of liquid chlorine (12.5%). I tested again in the evening - FC=15. Left pump running overnight. This morning, FC=13.

 

[kenlip]

Not looking good. Last night, about an hour after dosing with 600ml of chlorine, the FC level was 13. This morning, before sunrise, it was 7. Clearly, something is wrong. I might be messing up the testing, but it's not exactly rocket surgery so I doubt that's the problem. Looks like there is something, presumably algae, consuming the chlorine overnight. I guess I just have to continue with the SLAM.

 

[sktn77a]

Bright sunlight causes free chloring to degrade. That (summer down under) and algae are probably the cause, rather than any filtration/flow issue. You should probably increase your alkalinity and hardness, too - your water chemistry is pretty corrosive right now.