Wow.... Bleach consumption cut in half with a solar cover

[leejp]

Last sunday I installed a solar cover on our 18x36 26KG IG. Prior to the solar cover I had been consuming 2~3PPM/day with the CYA @~50.

The past week with the cover on I am down to 1~1.5PPM/day!

With the cover, I can keep the water temperature up and literally cut my bleach costs in 1/2! Why didn't I do this sooner?

[sunofthebeach]

I am on the other end of that.

This is my 1st year without a solar cover and I can't believe how much bleach/chlorine I am using.

[CarlD]

The cover will prevent chlorine from gassing off as fast. It may also block some of the UV rays that break FC down. If you have an opaque cover, blue on top, black on bottom, it will block far more UV, but may not heat as well.

We had, as our first pool, an Intex Donut. I would keep an opaque solar cover on it, then use the Intex pool cover, which tied over the sides, when we weren't using it or rain was on the horizon. Between the total blocking of UV, the almost complete prevention of gassing off, and the virtual blocking of contaminants getting into the little donut, I would find chlorine levels would be stable for days at a time, even as long as a week. Going on vacation was a snap--shock the pool and cover it and two weeks later it was fine.

[fog80]

Looks like I'm getting a solar cover. Which one is the best at heating the water?

[Spensar]

Looks like I'm getting a solar cover. Which one is the best at heating the water?

The heating effect is minimal for any of them. What it does do well is greatly help to retain heat overnight when the air temperature drops and you have a difference between the air and water temperature and without a cover your pool becomes a huge evaporation pan.

[CarlD]

I'm not sure where Spensar is getting his information. The insulating part is correct, but the heating part is not.

Solar covers can be VERY effective at heating your pool. They aren't nearly as effective as solar panels but they do work. It's just a matter of how much heat you need.

There's some debate as to whether opaque covers or clear covers work better. Opaque covers work by heating up and transferring the heat to the water by conduction. This does work and the water 4 to 6" below the cover will be quite warm, even hot. This then has to be distributed by the filter.

Clear covers work by acting as a greenhouse. The sunlight penetrates the cover, heats the water but the heat is trapped, rather than dissapating up into the air. This, too can be very effective.

Clear covers seem to work better when they are thicker providing more insulation.

My personal opinion is that thick, clear covers work best, followed by other clear covers, which are pretty much the same as opaque covers. Blue transparent covers are the worst. They don't pass enough light to heat effectively, but they don't heat up enough themselves to conduct heat to the water.

No matter the warranty all covers seem to go after about 3 years. They stretch (mine is already 2' longer than it was), then the bubbles start to pop. When they are rolled, it's best to keep them covered with a white opaque cover. Otherwise the sun bakes them and the inner layers get like an oven and start breaking down.

One thing I don't understand is why opaque covers are blue on top and black on bottom. I would think that black on top would absorb far more heat to be transferred.

Anyway, I've had experience with all three types and go for the thicker, clear covers now despite the expense.

A good roller is also a must. Those plastic rollers do not hold up, but I'm much happier with a metal-framed roller.

[cleancloths]

They are probably blue on top of the black for aesthetics - blue is nicer to look at.

[Spensar]

I'm not sure where Spensar is getting his information. The insulating part is correct, but the heating part is not.

Anyone I know in my neck of the woods that has a cover doesn't get much benefit from an increase in pool temperature. I am in Ontario and not in a real temperate area like you have in a lot of the US, so that is a caveat.

I cover my pool daily and tried not running the heater to see what the cover does alone. It didn't do much for raising the temp - you may get a couple of degrees, and it is at the top as you indicated. But the thermocline is thin and in our 16x32 inground pool the net effect isn't much. Perhaps if you are looking to bring water at a not bad temperature up a bit to a more comfortable zone, the cover will have some effect. No way in our area does sloar cover bring what was colder water up 5 degrees or so. That is heat increases attributable to the incremental benefit of a cover since even without a cover the water temperature will increase in hot sunny weather.

Anyway, that's IMHO and experience for conditions around Ottawa.

I just didn't want someone buying a cover and thinking it will give them a heat boost and be dissapointed. That has happened to a number of pool owners I've spoken to around here. Often summer night temperatures are a lower temperature than pool water and the cover helps to preserve the heat, even without a heater. I would recommend a cover for that reason and take whatever heating as a bonus.

I'll defer to the pros for other locations and my original statement may have been to broad.

[leejp]

I'm skeptical that the solar cover provides "heating" to the pool water. What the cover does for me is retain the heat when the temperatures drops at night (50~60*F around here recently).

I used to watch steam rise from the pool in the morning over my morning coffee... no more...

[CarlD]

It does both.

But if you don't have lots and lots of sun during the day (like 12 hours or more of direct sun) you'll not see a huge increase.

Still, if you really want to heat your pool, combine solar panels with the solar cover.

[Tredge]

It does both.

I have a very Deep pool (11' 40,000 gallons) and the first 2 years I had no cover on it.

These last 2 years I've had a clear cover and I can state with certainty that it does indeed make a difference (no experience with other colors). ~10 degrees for me if I keep it covered every night.

I've noticed it helps a lot with evaporation which makes perhaps 80%+ of the heat retention. The water a few inches under the cover gets very warm but doesnt make a huge difference once you stir it up...especially in a deep pool.

I've also tried the liquid fish and those do help but only 2-3 degrees at most under optimal conditions. They do make stuff float on the surface a bit better which helps keep the bottom a little cleaner...but thats hardly a reason so use them.

[CarlD]

Yeah, evaporation is endothermic so it sucks energy (ie, heat) out of the pool when a breeze is blowing. You lose water AND heat at the same time...plus you have heat loss due to convection--the warmer water rises to the top because it's lighter, it warms the air above it, which gets lighter and rises, dropping more cool air onto the water, which now has to heat it....etc.

[deanbrew]

About a month ago when I opened my pool and put the solar cover on, it heated up about 3 degrees per day - went from 69 to 72 to 75 to 78 to 81 in four sunny days. I very much doubt I would have gotten that kind of increase without the solar cover, particularly since a couple of those days were sunny but not hot. Certainly, it helps the water retain heat at night, but I also think it adds heat, especially on a sunny day. I leave it on almost all the time, except in the middle of summer when the pool water gets too warm and feels like bathwater.

[fog80]

About a month ago when I opened my pool and put the solar cover on, it heated up about 3 degrees per day - went from 69 to 72 to 75 to 78 to 81 in four sunny days. I very much doubt I would have gotten that kind of increase without the solar cover, particularly since a couple of those days were sunny but not hot. Certainly, it helps the water retain heat at night, but I also think it adds heat, especially on a sunny day. I leave it on almost all the time, except in the middle of summer when the pool water gets too warm and feels like bathwater.

what kind of cover do you have (color, opaque etc).

I am looking at purchasing a cover and roller set from BJ's but I'm not sure if it is the right one.

[brent.roberts]

I recently went into a local major pool store and asked for a clear cover and they looked at me like I had rocks in my head.

I suspect the "blue" idea was to attract attention to the "product" to help sell more.

If you want to keep solar gain down in a car or in a room in your house, you tint the windows don't you ????

So they tell me the blue cover generates heat. Yeah sure. Then they put in the air bubbles that create an insulation layer the keeps a large part of that heat on the top surface of the cover. No thanks. Give me clear. Let the radiation penetrate the pool as much as possible.

My wife likes it at 90 degrees.

We are heating a 16x32 IG with solar panels and have a lot of wind in top of the hill where the pool sits. The water loss through evaporation is terrific. Maybe Chem Geek can tell us how many calories are lost when 1/4" of water evaporates. It's a big number and will translate into a lot of degrees.

I find the biggest reduction in loss is at night. To conserve your heat make sure you cover at night.

If your pool is in a well protected area and not subject to much wind, covering during the day is not so important, but will still make a difference.

With the tests I've tried, get a clear cover, run the pump intermittently so the water is moving under the cover and transfers the heat away from the cover resulting in less loss back up throught the cover.

The "heavy duty diamond" covers are just that ... heavy. After they start to break down and some bubbles break and others lose the air in them, they don't float to well. That means water on top of the cover and that means evaporation again and ..... why did we put the cover on the first place ... to stop the evaporation.

Get the lightest, clearest, cheapest cover you can find. It won't last anyway. Keep the water off the top of it. Protect it when its rolled up and you'll get the best bang for your buck.

You can tell this is a favorite rant of mine.

Good luck

[fcfrey]

Just to throw in my 2 cents. I have had 3 different colors over 5 years --- silver, Blue and now a clear "Extruded" one. I bought this one from SPC this spring http://www.poolproducts.com/ I am very satisfied with this one and do get temp gain ---- the other thing they state is that they do not have to be covered when they are rolled up. Mine has a 10 year warranty (manufacturers defects) which does not mean much since they will blame failure on chemicals anyway.

[deanbrew]

what kind of cover do you have (color, opaque etc).

I am looking at purchasing a cover and roller set from BJ's but I'm not sure if it is the right one.

Mine is just a basic blue cover, sort of like bubble wrap. Not the absolute cheapest, but fairly inexpensive. I'm sure there are colors and styles that might do a better job, but this one works pretty well.

[chem geek]

The ideal cover would totally block UV light so that chlorine won't breakdown from sunlight's UV rays. It would completely pass through visible light and most infrared. It would completely block heat from convection and diffusion (very little gets radiated back out from the pool as infrared -- it's not THAT hot) so would be a good insulator for heat.

I don't think such a cover exists. Most that pass through sunlight seem to pass through a lot of UV. So the clear bubble pack variety are probably best if you want heating since they pass through most of the light while still being good insulators. If you want to minimize chlorine loss, then an opaque cover is best though a blue cover MIGHT block UV (since it reflects blue) while letting other visible light through (or it might let blue light through -- ideally it would be like blue-blocker sunglasses that look orange when looking through them).

My own pool cover is an opaque safety cover and changes the heat loss at night from around 6F without the cover to 3F with the cover. If I had a true solar cover (bubble pack) the pool would probably lose half what it currently does -- probably around 1.5F. But at least I can roll mine with an electric motor so the convenience outweighed the lower insulating efficiency.

Richard

[PhantomAndy]

5 years with my 18x36 IG in Kentucky. I started using a solar cover the first year. When it got a split personalily (delaminated) after the 2nd year, I didn't use a cover (3rd year).

My pool gets tons of sun, from 9am until 7pm.

My experience has been that 1) the solar cover holds in heat very well by way of stopping evaporation overnight. 2) I get a faster heat gain during the day WITHOUT the solar cover on.

These are general rules that apply on 'average' summer days. At the beginning and end of the swim season when the daytime temps are cooler, or when the temp is below average, or it's going to be windy, the temperature is maintained better WITH the cover on.

Regardless of your views on temperature gain, the reduced Cl usage is an undisputable fact. If you have the cover on during the day, you will lose less chlorine.

CarlD's recommendation on the solar reels is on target as well. They are a must if you have a pool of any significant size, and the plastic reels have a limited life. Mine has a plastic frame on eihter side and an alluminum tube for the width of the pool. It's still working 4 years after I bought it, but I'll be lucky to get another 1 or 2. The sides are sagging and warping. (It's the Europa model, I purchased at Leslies).

Good luck,

[stelr92]

I too would like to say that getting a solar cover has been a worthwhile purchase for my little 18foot round pool. I really like to have the water warm, and with the midwest heat that we have been having lately and abundance of sunshine, my pool has been sitting at a spa like 100 degrees for the last week now. I am just using a blue cheapie that I got for 60 dollars, I notice that after a good 4 - 5 hours of sunshine, the water in the first foot or so really heats up, so I have my pump filter set to go from 11:30am - 12:30pm, then again at 5:30pm - 12:00am so I can circulate as much warm water as possible. Last season without the cover the warmest the pool ever got was 82 degrees, and this was with a few straight weeks of 100+ degree temps! Other advantages include the amount of chlorine the pool needs has greatly reduced, and loss of water due to evaporation is also greatly reduced.

[NWMNMom]

We have had a variety of sizes of pools over the last many years, but 2 yrs of our larger pool - with all of them we use the blue covers, not the cheapest, not the most expensive. With the smaller pools (15', then 18') we saw a greater temp increase due to the smaller volume. We do use panels and have for several years so we try to differentiate the temp differences caused by each. The most obvious is the top 4-6" of water on very sunny days - SUNNY, not just warm because there is no difference there from the cover. Usually we can only tell that before the pump timer has come on or we have water circulation that stirs up that top layer to some extent.

The cover KEEPS my generated heat in the pool
The cover can (but does not always) heat the top few inches of water, mostly only when its hot AND sunny

Another bonus is that the cover keeps additional crap from falling into the pool. I like that part - less cleaning for me.

Cover = good investment