Filter question

[featherless]

Hi,

I have a cartridge filter but I find it to be a pain in the butt to maintain so I am wondering if the other types of filter would make my life easier. It cost me $400 to replace the cartridges and I must do them every 2-3 years. Actually, every two years would be ideal because by the 3rd year, I must clean the cartridges every other month to keep the pool clean.

I get lots of debris from trees and dirt into the pool. I wondering if the other types of filter, DE or Sand, would require less effort on maintainance and cheaper to own over time.

[Larry]

Hi featherless and welcome to the Pool Help Forums

I have always found sand filters the easiest to maintain. Cleaning/ backwashing takes only a few minutes and you don't even get your hands wet. The sand (or zeolite) in the filter needs checking and replenishing no more than once a year.

On the downside, sand filters cannot trap particles much below 20 microns, so they do not provide the same filtration that a cartridge or DE filter does. With zeolite instead of the quartz/ silica sand, filtration improves and does become comparable.

Backwashing results in a relatively large volume of water being pumped down the drain and this is an issue in areas where water is in short supply and restrictions on use apply. A typical backwash cycle can "waste" several hundred gallons of pool water. This is also water that you have spent money on balancing with chemicals. I personally like the idea of a partial water replenishment on a regular basis and am happy to live with the added expense.

Sand filters are also bigger and consequently need a larger area than the typical cartridge filter. I don't think this is generally a major consideration, but it has been a deciding factor in several pump rooms we have redone.

Larry

[featherless]

Thank you for the quick response Larry. Fortunately I live in an area where water is not heavily restricted. But there's not a lot of room at the side of my house so I am not sure if I can fit in a sand filter.

How about the DE Filter? Are they difficult to maintain? The salesman at Leslie pool told me that the DE panel can last up to 7-10 years; requires 2-4 backwashes each year, and I only have to open it up and clean it once a year. Is this really true?

[Larry]

DE filters are the most labor intensive. They require DE coating of the grids after each backwash and should be stripped and cleaned once or twice a year. You have the additional ongoing expense of the DE powder. Admittedly the DE filter will trap particles that cartridge or sand filters can't.

If maintenance is the main factor take a look here for a detailed explanation of DE filter cleaning and then rethink it.

the DE panel can last up to 7-10 years

But does it? There are too many factors to say. It will last at least as long as your warranty and should last more than twice that time.

requires 2-4 backwashes each year

Also this so much depends on your pool, the environment, bather load, fill water and a million other factors. You may find your filter requires a backwash every month or more. Ask your neighbors how often they backwash to get a better idea. Sales talk is often misleading.

Larry

[Ray1031]

Hi,

I have a cartridge filter but I find it to be a pain in the butt to maintain so I am wondering if the other types of filter would make my life easier. It cost me $400 to replace the cartridges and I must do them every 2-3 years. Actually, every two years would be ideal because by the 3rd year, I must clean the cartridges every other month to keep the pool clean.

I get lots of debris from trees and dirt into the pool. I wondering if the other types of filter, DE or Sand, would require less effort on maintainance and cheaper to own over time.

Though you have probably already made your decision, I will post a couple of considerations for you to consider anyway ... a couple of notes mostly in addition to what Larry has said ...

First, a quick comment about your cartridge filters: Something many pool companies do not tell you, especially since they make money one selling you new cartridges. Over time, especially in an area like yours where you have excesses of dirt and high tree debris problems, the pores or tiny openings in a cartridge filter become impacted and plug with debris - restricting the flow of water. A simple cleaning of the cartridge with water and brushes is not sufficient to re-open these pores. Once each year filter cartridges should be cleaned in a 50-50 mix of muriatic acid and water. After rinsing/cleaning the major debris from the cartridge, place it in a bucket of the acid mixture. As long as the bucket is tall enough to accept half of the cartridge, you can treat half and then 'flip it' to treat/clean the other half. It will 'foam up' as it cleans and will likely overflow the bucket ... so be sure you do this in an area you want nothing to grow. Muriatic acid in this strencth can kill even the microbes in the soil. The mixture will eat away the build up from the pores of the cartridge - making it close to new again - without damaging the cartridge itself. When it stops foaming ... the acid has done its work, though I usually allow the cartridge to sit for a few extra minutes to be sure. Rinse the cartridge thoroughly after, to remove the excess acid - it is a ph down agent after all.

Important note: Whenever you deal with muriatic acid: Wear rubber gloves and try not to breath the fumes. should you splash a little on your skin, flush/clean the area under running water. If you splash any on your clothing, I am sorry - it will bleach out any color and create yellow spots. The fumes from muriatic acid will "tell you" if you have any small cuts as well ... they will tingle. The more filters you have to clean, the longer each succeeding cartridge will need to sit in the mixture before it is cleaned, the acid will lose a little of its effectiveness with each use. A simple trick to deal with the over-foam from the bucket and for disposing of any excess acid after the treatment: While cleaning, place a garden hose on the ground "upslope" of the bucket so it is surrounded by a constantly moving flow of water. After the cleaning, place that same hose inside of the bucket and simply let it run for fifteen minutes or so. Muriatic acid, when diluted sufficiently, actually becomes a plant food, rather than a killer. The running water coutinuously dilutes the mix.

A fact about the DE (Earth) and Sand filter discussion ... First, yes - both DE and Cartridges filter finer than sand. However: The human eye cannot detect particles than 20 microns so seeing the difference between the 20 micron cleaning and the 8 micron cleaning is not really noticable (except possibly as a little less "snap" or "sparkle" to the water. As far as its being clean, you will not tell the diference. A grid type DE filter backwashes using the same method as a sand filter - using an equal amount of water to do the filter cleaning - the same loss to your pool level. The primary diference between the two (beyond the finer filtering capability- which I will return to in a minute) is that with the DE filter, the media (the granulated sea shells or powder) is flushed out with the water and deposited at the egress point. In a "replacement" situation, such as yours, this will usually be a roll up backwash hose that you pull out into your yard for discharge. Over time, as it builds up from coutinued backwashes, this deposit of earth will eventually kill your grass if you always backwash to the same place. With a Sand filter, the media stays inside of the filter and only the "debris" the filter has collected is backwashed out.

(quick note about backwashing: If anyone is concerned about the pool chemicals "killing" their lawn, do not be ... if the chemicals in the water were strong enough to kill grass - you could not swim in it. The only consideration here is to not backwash immediately following a large chemical addition.)

Now: the finer filtering capability: With a Sand filter, though it is true that the sand alone will not filter quite so finely as DE or cartridges, it can be made to ... They make a "Filter Aid", basically a lime-like or DE-like powder that can be added to a sand filter to make it filter finer. It is sold in three pound tubs and you add it to your sand filter (usually in one or two cup amounts - determined by your filter size) to make it filter much more finely. What most people will do with this, is to use just the sand filtering in day-to-day pool cleaning and add the powder for parties and special events when they want the water to have that "little extra sparkle". The consideration to remember here is that, with the finer filtering capability, it will cause your filter pressure to rise more quickly than normal and you will need to backwash sooner.

One final consideration in the Cartridge/DE/Sand comparisons ... Moving water. Sand filters are much more forgiving than either Cartridge or DE filters. Both DE and Cartridge filters can quickly plug to the point that your pump will not push water through them. When they reach this point, your pump can overheat and cause damage to itself, or to the plumbing surrounding it. This is especially possible should you ever run your pool without chemicals or when live algae is present. Live algae can plug one of these filters very quickly indeed. A Sand filter, on the other hand, will continue to move water when neither of the other two will ... the trap on your pump may not be full, but it will continue to move water and continue to cool the pump - preventing overheat damage. A good consideration for those who must travel a lot or go longer periods without being able to attend to the pool.

Ray

[featherless]

Firstly, I appreciate very much that both you gave me very detailed answers . Thx very much Larry for sending that link on DE filter cleaning... that was a real eye opener!

After analyzing the pros and cons of each filter type. I've decided to stick with cartridge and have decided to purchase the Starite Mod Media 3 filter. It uses 2 larger cartridges that fit into each other: one tall and skinny and the other fat and short. With this configuration, it is possible for me to soak both of them simultaneously over night.

Ray, I read on another website that I must remove the cartridges of oil and dirt before I give it an acid bath... otherwise it would close the pores permanently. That site also said that I could do a quick test by putting a small out of acid on the cartridge, if it foams, then proceed with acid bath. It seems like I can ruin my equipment if I am not careful - patient with the cleaning.

I've seen in other forums that people suggested using Cascade dishwashing powder to remove dirt and oil from the cartridges. Have you ever tried this before?

Once again, thx very much for helping out.

[Ray1031]

Ray, I read on another website that I must remove the cartridges of oil and dirt before I give it an acid bath... otherwise it would close the pores permanently. That site also said that I could do a quick test by putting a small out of acid on the cartridge, if it foams, then proceed with acid bath. It seems like I can ruin my equipment if I am not careful - patient with the cleaning.

I've seen in other forums that people suggested using Cascade dishwashing powder to remove dirt and oil from the cartridges. Have you ever tried this before?

Once again, thx very much for helping out.

I had not heard mention of Cascade in this application ... but as a grease cutter it should be effective. Dishwashing detergents can be some of the best grease cutters you can buy and are (today) mostly environmentally friendly. I find, in most cases, that it is not really necessary to use an additional grease cutting agent - except possibly for filters with problems in the spring. (With homeowners who simply pull their winter cover out from under all of the garbage it collected during the winter months - rather than pumping it off and dipping away the debris) In most cases, what greasiness there is clings to the actual dirt and debris collected by the filter, rather than the filter itself. A garden hose with a sprayer attachment is "usually" sufficient to clean 99 percent of this debris and grease from the filter before acid washing. For "problem" filters I, again in a seperate bucket or tub, use a vinegar soak. A cup or two of vinegar in a couple of gallons of water - soak for ten minutes - rinse well - then do the acid mixture soak - again; rinse thoroughly after.

As for damaging your equipment; I never do an acid filter cleaning in or around the pool equipment. While 90 percent of everything in your equipment is plastic and will not be affected by the acid, there are rubberized and ceramic seals to consider, and some metals which can be affected.

Ray

[JPlunket]

Ray, many thanks for leading an enlightening discussion!

I have an Endless Pool, 5000gal, TA is stuck high at 150, CH is above 500, so I'm now thinking calcium buildup in my filter is a problem. My water is crystalline, and the pool is covered with a bubble all winter, used daily, filter and heater run 24/7. But pressure at the filter --a weekly cleaning with hot water will get it down to 12 or 13 psi, but within the week it's back up into the 20s.

Had a recent bout with yellow algae, but beat it several weeks ago, finally. During that debacle, I often found the filter a bit slimy, but no longer. The filter remains a bit stained from the copper algaecide, but not heavily so.

I am going to try the muriatic acid wash. I bought a gallon of 31.45% Hydrochloric acid "20 degrees Baume".

FIrst I am going to wash thoroughly with a Cascade solution.

Please confirm what the water/acid mix proportion should be, and for approximately how long a rinsed filter needs to be (or should be allowed) to soak in such a mix. The filter will be fully submerged in the mix in a 10 gallon plastic bucket.

Many thanks

[JPlunket]

In the meantime, I've used a 50/50 mix of water/acid, let soak 30 minutes. Solution turned green, without much bubbling. THere were bubbles, but nothing close to a foaming action.

Put the filter back, and have lower pressure than I've seen in a while (correction of the psi's cited above: I've been no lower than about 17psi for months, and it has typically risen quickly to 27psi). Pressure after hosing off, then thorough cleaning with Cascade in hot water, then a 30 minute soak in acid solution is about 13psi, down from 25psi.

Any thoughts?

[Ray1031]

JPlunket

In the past I have used everything from about 25 percent acid solution up to and including 100 percent. But any acid solution above 25 percent will do the job sufficiently. The only diference between the solution strengths, for the cleaning, is the amount of soak time. Weaker solutions require longer soaks. "For your lungs though" ... the weaker the solution: the less fumes there are to deal with and the safer it is to work with.

A few simple rules of thumb when doing acid cleaning a filter:

Always do the acid cleanings outside - with plenty of ventilation.

If there is a breeze, always approach the job from the upwind side, so the fumes are blown away from you.

Always use rubber gloves when doing an acid bath ... there always seems to be the necessity to handle the acid covered filter at some point. If you get some acid on you - even full strength ... do not panic! Simply, quickly, hold your hands under running water, rubbing vigorously, and flush the acid away ... it takes a little time for it to affect human skin - but I do not dauddle in washing it away either.

Try not to breath the fumes ... acid fumes are caustic and can cause lung damage if you are not careful. A particle and fume mask is best, but I do many without one. I automatically hold my breath while over the work and step away, when necessary, to breathe for a few minutes ...

"Most Importantly": Never be in a hurry. Work slowly and carefully. My personal preferences are to fill the bucket with only enough solution to cover 2/3 of the filter, clean half of it, then flip it to complete the cleaning. This prevents having to reach directly into the solution for any reason.

As for the "time" involved ... under normal circumstances, for me, I am normally doing other things at the same time I am doing the cleaning - so it is nothing for me to allow the filter to soak for ten, fifteen or twenty minutes per side. The direct rule of thumb for muriatic acid though is "When it quits foaming - it has quit working" meaning it has supposedly cleaned everything it is going to get. The foaming usually quits in only a minute or two. If you allow the filter to sit longer though, it will not harm the filter. Ten minute per side is a good bet.

Remember to rinse the filter well after cleaning though .... not only is muriatic acid a ph down chemical, but it can also stain the filter if allowed to dry on it.

I say again .... Work Slowly ... pour slowly - splashing the acid onto your clothing will not only bleach them but weakens them as well ... Do Not linger over your work ... When you place the filter into the acid, lower it smoothly into the bucket and then immediately step away and wait ... Finally ... when using acid mixtures: use them in areas where you A) do not want things to grow anyway ... and B) do not care if a little spill-over stains or bleaches the area you are working in ....

Another use for this type of solution, in pool work ... has also been the cleaning of a dirty and stained concrete deck around the pool ... works great on concrete driveways as well.

Ray

[Ray1031]

In the meantime, I've used a 50/50 mix of water/acid, let soak 30 minutes. Solution turned green, without much bubbling. THere were bubbles, but nothing close to a foaming action.

Put the filter back, and have lower pressure than I've seen in a while (correction of the psi's cited above: I've been no lower than about 17psi for months, and it has typically risen quickly to 27psi). Pressure after hosing off, then thorough cleaning with Cascade in hot water, then a 30 minute soak in acid solution is about 13psi, down from 25psi.

Any thoughts?

Believe me, if there were a calcium buildup on your filter, you would have seen foaming and the color change would have been more towards the yellow, than towards green. To me, green tinting during an acid wash usually indicates the presence of live algae ... common algaes, not mustard/yellow algae. When you treated for the mustard infection did you also shock the pool and add a common algaecide? Quite often, as the mustard/yellow algae plays hell with your chlorine levels, it will allow the more common algae green and black varieties a "toehold" in the pool. These algaes are often somewhat protected from chlorine treatments by a greasy coating on their hides. Common algaecides are pretty much 70 to 80 percent soap and cleans away this greeasy coating so the chlorine can more readily attack the algae itself.

Ray

[JPlunket]

Ray,

Thanks again for the specifics. I actually followed most of your advice, based on what you said earlier in this post and a couple others. As noted the effect has certainly been salutary.

What do you make of the minimal bubbling and green coloration of the acid mix after the 30 minutes soak?

Is it the case that calcium builds up in the filter pores when CH is high (mine's 500). Does the acid soak clear the calcium out completely in such a short soak (30min)?

[JPlunket]

Sorry to be obsessive, but what would be causing my filter to clog so quickly?

conditions:
water temp 83
pH 7.2
TA 150+
CH 500+ (plain tap water is 200+)
CYA - ran the test, black spot disappears at 1.5-2ppm chlorine band
chlorine - I use powdered dichlor; had trouble keeping it up during yellow algae war; shocked multiple times, mistakenly using di-chlor; used copper algaecide a couple times; chlorine has not dropped below 5-10ppm for weeks now. Just shocked today with a gallon of 6% sodium hypochlorite, which gives me a 10ppm+ reading.

filter condition - during algae war, it would collect slimy build up, but that no longer occurs; some staining remains, probably result of copper treatments; clogging still occurs just about as fast, going from 17psi to 27psi in about a week. Now at 13psi, after rinse, Cascade, brushing, 30 min acid bath, thorough rinse.

unusual conditions, not sure they bear on this, but...the pool is covered with a bubble all winter; this may raise interior air CO2 level to well above normal, which may slow outgassing from pool water (?); I used to keep large rafts on the surface to keep evaporation level down, but stopped using them two months back, thinking the rafts themselves might have been algae-carriers; 10x16 water surface loses about 2 inches every 10 days, surely "helping" to keep CH high.

[Ray1031]

As I said in an earlier post, to me the green tint in the acid after the washing indicates the presence of algae in the filter (live algae). Question ... in your clorine tests are you testing for both total and "free" chlorine in your pool? Live algae is the fastest plugger of pool filters in the book. And pool chlorine can become "bound up". You can, with some of the simpler chlorine test kits on the market find your selftesting only the total chlorine levels in your pool - especially using the off the wall (drop type) chlorine testers. If you use drops to test your chlorine and the indication is in shades of yellow, then you are most likely testing one the total chlorine levels of your pool.

I have seen pools test out for massive amounts of chlorine and is was all "bound" ... the effective "free chlorine" in the pool was negligible/next to nothing. Bound chlorine is "there" and it can affect swimmers and pool surfaces ... but it does no "work" ... it will not attack the things in the pool water it is supposed to. Free chlorine is the chlorine in your pool that is actually working, killing the algae and other contaminants.

If your tester does not differentiate between the two types of algae for you, then I recommend taking a sample to a pool store and getting a free test done. If you have done this and they have not given you both a total and free chlorine reading - take a sample to a different pool store for testing. When in doubt, get more than one opinion. Always!

The only sure method for converting total chlorine to free chlorine is by shocking the pool. With your calcium levels, though it is more expensive, I would recommend using a lithium hypochloride pool shock rather than a calcium hypochloride.

As for your high calcium content ... My first suggestion is: If you use an automatic chlorine feeder with tablets/pucks/sticks ... or a standard granular broadcast chlorine ... or if you normally use floaters or place pucks in your skimmers - Stop! Switch to liquid at least for a while - until you get the calcium under control. Tablet and broadcast chlorines all normally contain calcium. I already mentioned the pool shock - though here too, you can use liguid rather than the granular.

As for lowering the calcium content of your pool, you have two methods: The first is Acid ... Muriatic Acid. If you use a granular ph down you can switch to using liquid muriatic acid instead. Over time it will slowly reduce your calcium levels. The problem here is "time" to do the job quickly you will be drastically lowering your ph repeatedly as you pour in the acid a couple of gallons at a time ... rebuild your ph .... the hit it with acid again ... and repeat until the calcium control is established.

The second method is also a little drastic, though normally quicker and less drastic in the ph and chemical department .... drain about half of the water from your pool and refill it. (Note here: if you have a liner pool "do not" go lower than about ten inches to 1 foot of water in the shallow end or the liner may shift on you ... the same can apply in a high water table area -especially in the spring- as you do not want to risk the pool "floating" on you.)

[Ray1031]

One final thought for you to consider as well .... the results of the filter cleaning and the recent algae problem you were having may be a little slow in resolving your filter issues back to a more normal running pattern.

In many cases after such problems, the pool takes a couple of weeks to actually return to "normal". As I indicated, especially with the mustard/yellow algae, side problems can develop that will clear themselves, but need a little time to do so. You may also find that in a week or two, after things have settled and your pool is acting more normally (chemically) - that your filter will need another cleaning before things finally revert to what is more normal for your pool..