Reduction of Backwash water loss ideas.

[JohnT]

I'm going to be moving my pool equipment later this summer when I build a poolhouse. I'm considering some changes to try to avoid having to add so much water due to backwashing. I live in a very rural area, so I have a significant debris load after storms or periods of wind. For this reason, I chose a sand filter, and still believe it is my best option. I also have well water that has seriously high alkalinity (I've measured it as high as 800). I used Ben's aeration method last summer along with a mesh cover to allow maximum rain water dilution over the winter to lower my initial alkalinity from about 280 down to 180, but adding well water to top off after backwashing could drive it back up. Here are my thoughts and ideas:

1. Truck in fill water. I have a trailer that could be dedicated most of the time to holding a tank, and the 280 TA water is available reasonably cheap. I'd still have to fight alkalinity, but not as much as with my well.

2. Install some kind of filter in the backwash line and return it to the pool. I've looked at the polishing bags, and if they work as advertised, they might be an answer. Wouldn't be quite as convenient as something plumbed in. I've also even considered getting a cartridge filter to use strictly to clean my backwash water. Downside here would be the added cost and cartridge cleaning required, but I would in effect have all the good things about a sand filter and a cartridge filter, but only the cleaning disadvantage of the cartridge to deal with.

3. Plumbing an extra suction line with a valve to let me backwash with tanked in water. This way I'd close the drain and skimmer valves, open the extra intake that would be connected to the tank, and backwash. This water would never go in the pool, and already balanced and chlorinated pool water would stay in there. I'd only have to replace evaporated water.

4. (The odd one) Plumb my well into the inlet side of the filter, so I could run well water through the filter set on backwash then rinse with the pump off. Same benefits as #3, saving me hauling tanked water. Net water usage is no more than I go through now, because I have to replace what goes out for backwash anyway. Unknown is whether I will accomplish any or enough cleaning with the reduced flow this method would provide. An added benefit would be that I could then add fill water via the returns and wouldn't need a hose. More complexity for winterizing though.


I'd be interested in any comments folks have. I'm considering trying #4 just because of the simplicity and the fact that it would be pretty reversible if it doesn't work. It might even be able to just reduce my backwash water usage.

Thanks,
John

[mas985]

John,

For #2, there is a device called a separation tank. They are actually required were I live for sand and DE filters. The sole purpose of these devices is to reclaim backwashed water. They have an internal screen/filter which removes the dirt/DE from the backwash and returns the water to the pool. Here is an example of one:

http://www.cheappoolproducts.com/Separation~Tank~for~any~Pool~Filter_52_1293~produc t.html

[mshumack]

You may want to just switch over to a cartridge filter. It takes a lot less water to periodically rinse/clean the filter .

[mwsmith2]

Yep, exactly what I was going to suggest. Not a convenient (IMHO) but a better solution for you I think.

Michael

[JohnT]

You may want to just switch over to a cartridge filter. It takes a lot less water to periodically rinse/clean the filter .

I had one in the past on an above ground pool, and didn't care much for it. I have a pretty significant dirt and debris load from surrounding farmland and woods that I'm afraid would be pretty annoying based on my past experience with a cartridge. It may have been that I had more dirt going into the previous pool than I was aware of, but I never got the life out of them that I was told to expect, and always seemed to be cleaning the cartridge.

[JohnT]

John,

For #2, there is a device called a separation tank. They are actually required were I live for sand and DE filters. The sole purpose of these devices is to reclaim backwashed water. They have an internal screen/filter which removes the dirt/DE from the backwash and returns the water to the pool. Here is an example of one:

http://www.cheappoolproducts.com/Separation~Tank~for~any~Pool~Filter_52_1293~produc t.html (http://www.cheappoolproducts.com/Separation%7ETank%7Efor%7Eany%7EPool%7EFilter_52_1 293%7Eproduct.html)

Worth considering. I've been reading up on them. Does the bag in the ones I'm reading about catch dirt and DEas it comes out of the filter? Thanks.

[JohnT]

A hitch in #4 pointed out by a co-worker is that pool water could be forced back into the drinking water line while the pump is on if the valve were to leak:(

[mas985]

Worth considering. I've been reading up on them. Does the bag in the ones I'm reading about catch dirt and DEas it comes out of the filter? Thanks.

I don't have one myself, but from what I understand is that they simply filter the backwash coming out of the main filter in the bag.

I figured that if I had to clean a sep tank bag, why not just get a large cartridge filter so I would only have to clean it out twice a year and save me time in the process.

[tphaggerty]

One small thing to try is the "skimmer socks" that were in another recent thread. These are fine mesh bags that fit inside of your skimmer basket. They really do pick up a LOT of stuff, including very fine stuff. We have a combination of high pollen and dandelion/cottonwood tree fluff here and the socks work great at keeping almost all of it out of the filter.

I keep several sets of these on hand, each time I empty the skimmer, I replace the sock with a cleaned/dry one and wash and hang out the old one. Keeps the labor pretty low and really does seem to significantly extend time between backflushing (with a DE filter).

[Poconos]

John,
Since you live in a rural area do you have a stream on your property? Water wouldn't be as clean as a well and you would have to shock it to get rid of critter doodoo etc but the TA would probably be a low lower. 800...wow. I have two wells and a stream and when fill is needed I use the stream. Also, any way to cat rain water from roof gutters, if you have them, and use that for fill? Just a couple thoughts.
Al

[duraleigh]

Hi, John,

I'm a sand filter guy, too.

I swear to you I have not been drinking (yet):)

Two sand filters. (plenty of folks giving up perfectly good ones cheap) Backwash one into the other. When the backwash cycle is complete, valve off the one you just dirtied up to remove it from the system.

Go back to filtering from the one you just backwashed. At your leisure, "backwash" the now "removed" filter with a seperate water source. What that source might be is the snag. I doubt a garden hose will do it so you'd have to probably cycle some well water through the pump into the filter which would call for another valve on the pump.

Hmmm, after rereading this post, maybe it IS time to start drinkin'!:)

[JohnT]

John,
Since you live in a rural area do you have a stream on your property? Water wouldn't be as clean as a well and you would have to shock it to get rid of critter doodoo etc but the TA would probably be a low lower. 800...wow. I have two wells and a stream and when fill is needed I use the stream. Also, any way to cat rain water from roof gutters, if you have them, and use that for fill? Just a couple thoughts.
Al

I do have a pond, but at the time when I most need to add water in the heat of the summer is when the pond is lowest, and I'm afraid the deal would be the same with catching rain water. I have considered that though, and am still seriously considering it for irrigation of landscaping. The part that hurts is that I have pumped more than enough water out of the pool due to rain over the off season to cover the backwashing and evaporation all summer. I always vacuum and backwash when I get enough rain that the water level is high to take advantage of it.

Our water is so bad that if you wash a car with it, you have to use the windshield washers to remove the film that is left on the windshield before you can drive! I have never used borax or baking soda in my pool, and probably never will. I started on my 5th gallon of muriatic of the season last night to get my pH down from 7.8 to 7.5. I don't want to make it worse! Thanks for the comments.

I'm leaning toward seeing what running tapwater through to backwash does for me during the move, just to see. Maybe it would cut my backwash time enough to be worthwhile.

[Poconos]

FYI with my little squirt stream, during really dry times, it's only flowing maybe 5 GPM. But so what. If I only get 1 GPM into the pool and it takes a 6 hours per inch with a 1/6 HP Flotec sump pump...so what. When I do fill from the stream I dump it into the skimmer so it's filtered before it hits the pool. Last year I was chasing a leak and had to use an old 1 HP Jacuzzi pool pump in the stream. Flow was good in the Spring. Ran the flow backwards thru the sand filter....put the filter in Backwash mode, fed the waste, clean filtered water came out the skimmer. Another trick.
Al

[cleancloths]

When we have had water restrictions rather than backwash my DE filter I would just take the band clamp off, open it up and wash it off with a hose. This would use maybe 30-50 gallons of water versus 300-500 when backwashing it. Actually gets the filter a lot cleaner than backwashing.