a few questions, water temp and backwashing

[matmo]

Hi everyone!

I have a few questions regarding my pool and was hoping the pool experts here can provide me some guidance:

1. My pool's water temperature reads 93 today?! The outdoor temperature didn’t reach higher than 85 today. How is this possible? I have not run the water heater in weeks, but the water did feel like 93 (ruling out malfunctioning thermometer). I have two theories:

1. The PVC piping for the drains and the skimmers run under concrete before the water gets to the pump (where the water thermometer is located in the heater). Perhaps the water is getting heated up under the concrete? I run my pump 24 hours a day. Maybe I should run the pump at night only for 6-8 hours? That way the water won’t flow through the pipes under the oppressively heated concrete?
2. My plastic auto cover may be heating the water, although I thought it really functioned to retain heat.

2. How often should I backwash? The pool installer said 1x a week, but reading around it seems like that might be excessive.

The measurements are all good and the water is so perfectly clean...it's just warm and I don't even know if I should be worried about that. :|

thanks!

 

[jbird0215]

I have found that full sun can really do a number on pool temp, but that is a big delta between air and water temp. The cover will help with heat retention for sure. I bought a cheap thermometer for the pool as I didn‘t trust the temp sensors in the plumbing. With respect to backwashing, only do so when filter pressure rises 25% above the norm. As an example, if norm for you is 10, then you’d backwash at 12.5. I can go for months without backwashing because I use skimmer socks that prevents a lot of gunk reaching the filter.

 

[matmo]

I have found that full sun can really do a number on pool temp, but that is a big delta between air and water temp. The cover will help with heat retention for sure. I bought a cheap thermometer for the pool as I didn‘t trust the temp sensors in the plumbing. With respect to backwashing, only do so when filter pressure rises 25% above the norm. As an example, if norm for you is 10, then you’d backwash at 12.5. I can go for months without backwashing because I use skimmer socks that prevents a lot of gunk reaching the filter.

Thanks much! Is there a way I can prevent the water temp from rising so fast and high? I typically keep the cover on at all times except when we're in the pool. Roughly 2 hours a day the cover is off and the water is directly exposed to sun and 1-2 hours after sunset too the cover is off too.

Are there any downsides, chemically, with the water being this hot? It's 10am and the thermometer reads 91 but the outside temperature is 81. The water definitely feels like its in the 90s. This is really bizarre.

Thank you for the backwashing tips. I'll keep monitoring the filter pressure monitor and will get me some socks!

 

[clambert1273]

Nope no problem with high water temps as us in AZ have warm water a majority of the summer

 

[mknauss]

This is really bizarre.

I suspect you would find only the top few inches of the pool water is that warm.