I would appreciate some advice determining what size/brand sand filter I should buy. I need to buy replacement filters soon which I estimate will be $350-400 for my system, so this would be a good time to make the change. i would like to switch to sand to lower my maintenance time. I really dislike cleaning the filters - takes forever to get them clean, and my unit was installed too close to the house so I always get bloody knuckles from the stucco, when taking off the clamp assembly. My pool is 18k gallons, and I run it 8 hours most of the year (swim season with solar heat is 8-9 months where I live). So at 37.5 gpm divided by 15 gpm sq. ft, I would need 2.5 sq. ft. - do I rounded to 3? As for brands, I have no clue or preference. My current stuff is all Hayward. I don't want to ask my original pool installers - found out well after the fact that they sold me a filter system twice as big as I needed. My pool store is fine for chemicals and repairs, but dummy me way overpaid for a replacement cell for my SWG. I could have saved $200 on Amazon and $75 install. Didn't realize that the thing just plugs in! Any assistance or advice appreciated.
Thinking about changing filter system
- Thread starter KarenMary
- Start date
Welcome to tfp, KarenMary 
For your 18000 gallon pool we would recommend a minimum 3.3 sq. ft. sand filter. Generally the filter size should be matched to pool volume.
For your 18000 gallon pool we would recommend a minimum 3.3 sq. ft. sand filter. Generally the filter size should be matched to pool volume.
alanpaul
0
I know you're up for a change in your filter system, but I wanted to clarify that your current cartridge filter should have been in the 275 sq. ft. range, so 300 sq. feet isn't twice the size you required, just a little generous.
In any case, here's hoping you get exactly the filter you want, and that it does the job perfectly for you!
In any case, here's hoping you get exactly the filter you want, and that it does the job perfectly for you!
alanpaul brings up a good point...your current filter is well sized to your pool and typically should only need cleaning a few times a season (or less). For cartridge filters, you can never be too big. How often are you having to clean it and what is your criteria for when to clean it?
alanpaul
0
And FYI, I noticed that your pair of cartridges cost about $300 at Pool Supply World.
How do you all calculate filter size? I obviously did it wrong. I clean the filter about once a month or six weeks in the summer. It runs clean at 10, and I clean it when it hits 15. It is pretty gross at 15. A contributor to cleaning is my annual gnat fest - dead ones cover the surface of the pool water regular. Off season, which is only a few months, I might clean it once or twice.
I'm throwing this out here, could a sand filter be plumbed in prior to existing cartridge as a easy to backwash prefilter?
Not sure on how to plumb.
Not sure on effects of water flow.
Not sure on how to plumb.
Not sure on effects of water flow.
- Oct 18, 2009
- 3,635
- Pool Size
- 6000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
KarenMary, I am wondering why your have so many bugs if you have it screened in. We have our pool screened in and have no bug issues.KarenMary said:
BYW these are selling for $107.90 on ebay http://www.ebay.com/itm/200812121944?hlp=false&var=
Hope this helps
I have a large palm planter and several potted plants. I think they live there. I am going to call my pest company Monday and get them to start spraying inside the cage and see if that helps.
alanpaul
0
KM,
For cartridge filter size, many here will divide your gallons by 66.
18,000 divided by 66 equals approximately 275, best choice square footage of cartridge filter.
Minimum would be 18,000 divided by 75, equaling 240 square feet of filter, so your smallest would be in the 250 square foot range.
Maximum would be anything over 275 square feet for your pool; (the closest next available size is 300 square feet -- what you have), along with any size larger which an owner would choose, recommended for less frequent cleanings.
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Perhaps you might find out if your pest exterminator can apply a solution to the palms and pots to kill the buggers!
-----
FROM THE INTERNET, courtesy of General Pest Control, Cleveland, OH:
Fungus gnats live and breed in soil that is damp and rich in organic content. Stir the soil of these plants with a stick and smell for a sour odor. A sour odor signals the presence of fungi in the soil which usually results from over-watering. The habitat of fungus gnats is not limited to indoor plants. Outside, fungus gnats may be found in accumulations of dead leaves, rotting firewood, compost piles, and in heavily mulched areas that are shaded and constantly over-watered. Infestations have also been found in walls or ceilings where an undetected leak was present, in pet feces at the bottom of cages, and in the drip pans under refrigerators.
The key to control is finding and eliminating all of the breeding sources. Careful inspection is important. Look for both large and small potted plants. The eggs and larvae can be killed by drying out the soil. The larvae tend to live in the top layer of soil. Stir or overturn the top two to three inches of soil to speed drying. If the top layer of soil remains dry the larvae will die off and the adults will not have a suitable place to lay more eggs. Adjust the watering schedule to prevent the soil from becoming too moist. Conversely, be careful because too little watering may cause leaf drop and/or weaken the plant making it susceptible to fungus gnat larval damage. The soil may be treated with an appropriate potted plant spray that is commonly found in supermarkets, garden centers, and florist shops or by a licensed plantscape specialist. The common method is to use an insecticide as a drench so that the first one to three inches of soil are made wet. This kills the larvae and interrupts the breeding cycle. Alternatively, a bacterial soil drench containing Bti (Bacillus thuringiensis), commonly available as Gnatrol or Knock-Out Gnats, may be applied.
Once the larvae feeding in the plant soil have been killed, the adult flies will die off in a week to ten days. The adult flies may be trapped by using yellow sticky cards placed close to or directly on the surface of the soil. Adult fungus gnats may also be captured on the sticky boards inside of insect light traps. In severe situations, and only as a last resort for indoor infestations, it may be necessary to treat localized areas with an aerosol spray containing natural pyrethrins.
For cartridge filter size, many here will divide your gallons by 66.
18,000 divided by 66 equals approximately 275, best choice square footage of cartridge filter.
Minimum would be 18,000 divided by 75, equaling 240 square feet of filter, so your smallest would be in the 250 square foot range.
Maximum would be anything over 275 square feet for your pool; (the closest next available size is 300 square feet -- what you have), along with any size larger which an owner would choose, recommended for less frequent cleanings.
------
Perhaps you might find out if your pest exterminator can apply a solution to the palms and pots to kill the buggers!
-----
FROM THE INTERNET, courtesy of General Pest Control, Cleveland, OH:
Fungus gnats live and breed in soil that is damp and rich in organic content. Stir the soil of these plants with a stick and smell for a sour odor. A sour odor signals the presence of fungi in the soil which usually results from over-watering. The habitat of fungus gnats is not limited to indoor plants. Outside, fungus gnats may be found in accumulations of dead leaves, rotting firewood, compost piles, and in heavily mulched areas that are shaded and constantly over-watered. Infestations have also been found in walls or ceilings where an undetected leak was present, in pet feces at the bottom of cages, and in the drip pans under refrigerators.
The key to control is finding and eliminating all of the breeding sources. Careful inspection is important. Look for both large and small potted plants. The eggs and larvae can be killed by drying out the soil. The larvae tend to live in the top layer of soil. Stir or overturn the top two to three inches of soil to speed drying. If the top layer of soil remains dry the larvae will die off and the adults will not have a suitable place to lay more eggs. Adjust the watering schedule to prevent the soil from becoming too moist. Conversely, be careful because too little watering may cause leaf drop and/or weaken the plant making it susceptible to fungus gnat larval damage. The soil may be treated with an appropriate potted plant spray that is commonly found in supermarkets, garden centers, and florist shops or by a licensed plantscape specialist. The common method is to use an insecticide as a drench so that the first one to three inches of soil are made wet. This kills the larvae and interrupts the breeding cycle. Alternatively, a bacterial soil drench containing Bti (Bacillus thuringiensis), commonly available as Gnatrol or Knock-Out Gnats, may be applied.
Once the larvae feeding in the plant soil have been killed, the adult flies will die off in a week to ten days. The adult flies may be trapped by using yellow sticky cards placed close to or directly on the surface of the soil. Adult fungus gnats may also be captured on the sticky boards inside of insect light traps. In severe situations, and only as a last resort for indoor infestations, it may be necessary to treat localized areas with an aerosol spray containing natural pyrethrins.
I would echo harley's post. I have a cartridge filter and I would have to add a line to the main sewer line if I switched to a sand filter. It would cost several hundred dollars just to add the drain line.
BTW, I love my cartridge filter. I only need to clean it once a year.
BTW, I love my cartridge filter. I only need to clean it once a year.
I agree with HouTex, I love my cartridge filter! It is sized 3 times larger than I need and I only clean it every 9 months. It beats having to backwash all the time and replace water. Given that, if you have a LOT of debris a sand filter might be a better choice.
If I can get rid of the gnats, I will probably have to clean it a lot less. I'll let you know how it goes. Thank you all for the great advice. Just might keep what I have. Always something else around the house to spend money on...
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