Just got solar cover - 2 questions

[Boko]

I just bought a clear, 12 mil solar cover for my pool and put it on for the first time yesterday evening. The water temp was 80 when I went to bed, and this morning it was still 78! Losing only 2 degrees is an amazing improvement since I usually lose 5 or 6 degrees each night. Every degree is a big deal for me because I live in a wooded area and the pool gets a lot of shade. The warmest my water has been this year was 82. The warmest it's ever been was around 84-85 during massive heatwaves.

My first question is about leaving the cover on or off during the day. I've read that leaving the cover off will probably heat the water faster than leaving it on if it's warm, sunny, and not too windy. But how windy is too windy? Today is forecast to be sunny and warm (high of 89), but with 10 mph wind. And, if this is a factor, there will be low humidity (30 - 40%). I'm wondering what's the best thing to do on a day like today. It may not make a huge difference either way, but even a small increase in temperature can be the difference between my skinny kids getting blue lips and leaving after 20 minutes, or staying in and enjoying the pool.

Question #2 is about chlorine loss. I know that the cover will keep the chlorine in my pool longer. I'm going away for a week and my plan was to bring the FC level up to about 18 with liquid bleach before I go. I lose around 2 ppm daily, so I figured I'd be around 4 ppm when I get back. My CYA is 30. Since I just put the cover on, I don't know what to expect for FC loss now. Should I stick with my original plan, or put in less chlorine before I go?

Thanks in advance!

 

[swoopman]

Congrats on the new solar cover.

#1 - I'm no help with your actual question, sorry. However I'd like to pass this along - I have a friend who is skinny and gets cold quickly in cooler water like that. She wears a shorty wetsuit and can spend hours in the cooler pool wearing that. July 4th weekend I had my grown kids over and my daughter and DIL took turns wearing it and thought it was great (cold spell right before holiday dropped pool to 80 degrees). My friend also bought wetsuits for her grandkids and they love them since they can enjoy the water instead of getting chilly. The grandkids have these: Sporti Kid's Thermal Suit at SwimOutlet.com Hers is similar to this: Amazon.com: Os Reactor Short-Sleeve Spring Wetsuit

#2 - The chlorine loss is percentage based. Here's how JasonLion explained it on this thread How to plan for maintenance during trips / vacations? - there's a good discussion there that may be helpful for you:
"Here is a simple example, imagine that you are losing 2 ppm of chlorine each day, and you have a minimum FC level of 2, so you normally raise FC to 4, and the next day it is 2.

Now say you want to go away for a week. By your proposal we multiply 7 days by 2 ppm, giving 14 ppm. Lets add 2 more ppm just to be extra safe, giving 16 ppm. Now since the pool is actually losing 50% of it's starting FC level each day, not a constant 2 ppm, the actual FC level at the start of the day will be:

Day 1: 16 - the day we leave we raise FC up to 16
Day 2: 8 - each day we lose 50%
Day 3: 4
Day 4: 2
Day 5: 1
Day 6: 0.5
Day 7: 0.25
Day 8: 0.125

Most likely, somewhere during day 5 the pool will start to get algae, by day 6 the FC level will fall to zero, and we will come home to a green pool.

Simply raising the FC level extra high works well enough for three or four days, but beyond that it is impractical. For longer trips you need to take additional steps, like using a UV opaque cover or putting in a tablet feeder or both."

So, you'll need to do something more than just raise FC before you leave. It seems your cya is low enough that you could use a floater with pucks.

 

[ping]

1. I've had clear and opaque blue solar covers and in my case the water always warmed up more with the cover left on than with it off. You will learn that it is a bit of a pain to remove the cover every day if you are not swimming. If you do leave it on make sure you uncover it for one day a week which will prevent CC's from building up. When my pool is covered it usually has .5 CC and is 0 CC if it is left uncovered.

2. Raising the FC to 18 is a bit high for a CYA of 30. The cover will be exposed to some harsh conditions with the FC that high. I would raise the FC to 12, put a dose of polyquat 60 in the water, fill a floater with pucks, and cover the pool.

 

[Boko]

Thanks for the replies - lots of good info. I'm going to get my kids those wetsuits. They're 6 and 8, so even if it doesn't help them stay warmer they can have fun pretending to be superheroes!

That chlorine loss thread was very good. Looking back at my log, I do lose a lot more FC per day when the levels are high. I never noticed because I keep it between 2 & 4 pretty consistently. I guess pucks and a floater are in my future.

I hadn't considered the effect of very high FC on the solar cover. Yet another reason not to go crazy and just put in some pucks. I'll try to pick up some polyquat 60 before I go too.

Thanks!

 

[swoopman]

Thanks for the replies - lots of good info. I'm going to get my kids those wetsuits. They're 6 and 8, so even if it doesn't help them stay warmer they can have fun pretending to be superheroes!

That chlorine loss thread was very good. Looking back at my log, I do lose a lot more FC per day when the levels are high. I never noticed because I keep it between 2 & 4 pretty consistently. I guess pucks and a floater are in my future.

I hadn't considered the effect of very high FC on the solar cover. Yet another reason not to go crazy and just put in some pucks. I'll try to pick up some polyquat 60 before I go too.

Thanks!

Glad everyone was able to help you out. My GK's are 4 and 6 and they love the wetsuits, both for pretending and for warmth ;-). It says it on the page I linked but wanted to point out that the sizes do run small.

Hope you have a great vacation!