Hi all, I've been meaning to write up my 'pearls of wisdom re. DE filters' for a while, with some of our members already firing up their pools, I figured I better get it posted

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Use and Care For most DE Filters:

(The units I have a lot of experience with are made by Hayward – so most of this applies specifically to them, but the principals apply to all DE filters)

1) Basics –

A DE filter is one which uses diatomaceous earth (~ skeletons or fossils of prehistoric one celled plants) to remove all but the finest material from the water. The DE is a white powder which is mined in various places around the world which was formed by the evaporation of the water that these critters lived in. The DE is kept in the water flow of the filter because it coats the internal grids or fingers which make up the filters internal ‘nest’ allowing dirt and debris to be captured by the microscopic paths created by the coating. Because of the nature of the ‘paths’ through the DE coating, algae – which is the approximate size of the paths – can easily and quickly congest a DE filter, most DE filter owners find this to be the biggest drawback of owning one. The DE must be added to the filter via the skimmer, with the pump running, the amount to add is dependent upon the size of the filter. When adding DE to a filter, most manufacturers recommend mixing the powder with water before pouring it into the skimmer – I have found that adding the powder directly into the skimmer is equally effective, if you have more than 1 suction source operating at the time of addition. (having a second, or third, suction source allows the DE rich water from the skimmer to properly mix with ‘non- DE water’ from the other source(s) to evenly coat the grids).

However, DE filters, while providing the finest filtration, DO have their downsides! If you do a ‘backwash’ (discussed later) or do a thorough cleaning of the filter, you need to add more DE to it – and, if you add too much or too little, you’ll likely have filter problems! Too much DE will clog the filter and decrease the efficiency of it. Similarly, too little DE will not catch enough ‘dirt, etc” and cause the grids to clog up with the debris, both of which require a manual cleaning of the grids and possibly a chemical cleaning of them. Also, ‘bleeding’ the air out of the unit before adding DE is KEY! – the fresh DE can only coat the parts of the grids that are in water!

Knowing how much DE you are actually adding to the unit is VERY important! The best way is with a premeasured scoop – they are inexpensive and well worth the $ spent, any place that sells DE should have one available. DO NOT USE a 1lb. scoop or canister that is not specifically for DE (ie. A 1 lb. coffee can only holds ~ ½ lb. DE) If you have an accurate scale that will allow you to weigh the container first and then the weight of the DE when it’s full, that’s fine -- just be SURE to know ~ how much DE you add when you are adding it!

2) Types –

There are 2 different types of DE filters:
The first uses ‘fingers’ (fabric wrapped hollow tubes, usually 100/ filter) to collect a layer of the DE on. This style is also known as a ‘bump’ filter because the DE can be ‘recharged’ via the use of a handle which moves the whole assembly up and down to expose new pathways in the DE coating without having to replace any DE (I’ll talk about ‘bumping” a filter in a minute.) (There are some ‘grid’ filters which have a handle on the top connected to a plastic plate which operate the same way)

The newer models have a series of grids to collect the DE and either have a multiport valve or a ‘push/ pull’ valve (of which I will speak very little). These units allow you to ‘backwash’ most of the DE out when the filter needs to be cleaned. (* some localities do not allow wasted DE to be flushed into sewers or even onto your own property – in that case a ‘separator’ would need to be installed on the backwash line).

3) Start - Up

The fabric which holds the DE does very little to filter the water! As such, a DE filter needs to have a coating of DE on the grids/ fingers as soon as the pool is started up. Your installer or pool tech should do this for you the first time and give you a complete lesson on operating your pool (called ‘pool school’- it’s a lot of info all at once and it is very understandable that some of the info is forgotten by a pool owner). The amount of DE required by each filter is determined by the size of the filter – there should be a label on the filter identifying the size of the unit and how much DE it requires when completely clean. As said, KNOWING how much DE you are adding is key! Make sure to note what the pressure gauge reads when the unit is clean and freshly coated with the DE!!

4) Maintenance

Your filter should run anywhere from 8 psi to 20 psi with fresh DE put in it, depending on your pool and filter system. When the psi rises 8, it’s time to clean the used DE out of it. (when doing any filter work, turn off the pump

Bump filters:
1) open the air valve on the top of the unit for ~ 5 sec. and close (bumping with the unit full of water will harm the unit!)
2) Slowly push the handle down and quickly raise it up 4 – 6 times.
3) Now turn the pump back on and see if the psi went down, if it didn’t drop more than 2 psi, you need to dump the used DE.
4) (if you need to dump the DE) – Open the drain outlet on the filter after doing steps 1 and 2 and run the pump for 20 seconds. Close the outlet and run the pump for a minute (don’t do this if you have an algae problem! The uncoated parts of the fingers will collect algae too quickly and clog), then repeat the procedure (make sure you open the air relief while the pump is running until water comes out of it)
5) At this point, you have removed ~ 80% of the old/ used DE so only add 80% of the DE you would use in a new or fully clean filter!!

Grid filters:
1) Pretty much the same as bump, except you have a multiport which allows you to backwash the filter when the pressure rises 8 psi.
2) (always!! Turn off the pump when changing multiport positions!!) Turn the multiport to ‘backwash’ and restart the pump, watch the view-glass or the end of the discharge hose to see when the backwashed water becomes ~ clear. When it is fairly clear, turn the multi to ‘rinse’ for 15 – 20 seconds and then back to ‘backwash’ until the water runs ~ clear again. Repeat the ‘rinse/ backwash’ until the water comes out clear when backwashing, add a short ‘rinse’ and the filter is about as clean as you’ll get it using the ‘backwash’ function.
3) If the water in the pool is fairly clear, I’ll throw in a 1 min filter cycle and do the ‘backwash/ rinse’ cycle(s) again.
4) At this point, you have removed ~ 80% of the old/ used DE so only add 80% of the DE you would use in a new or fully clean filter!!

When bumping/ backwashing doesn’t work:

Sometimes just ‘dumping’ the old De isn’t enough to get you back to proper filter performance – this can be caused by algae (or some other fine debris clogging the DE), or neglect (you didn’t clean the filter soon enough), or the grids/ fingers getting clogged up.

At this point, you need to take the filter apart and manually hose them off (it’s a wet process – so be prepared to get ~ soaked). I recommend the manual hosing every year (I like doing it in the fall when the pool is being closed because, then you know the filter is ready for another season)

If , when manually rinsing the grids, you notice that water is staying in the membrane for more than ~30 seconds, it’s time for a chemical cleaning!

To chemically clean the grids/ nest:
1) Have a bucket/ container large enough to hold the entire assembly
2) #1 Add some TSP (tri-sodium-phosphate) to the water or some electric dishwasher detergent to the water and soak the grids for 3 hours – this will ‘de-grease’ the membranes and is the first step in cleaning them, rinse with hose and get ready for step 3.
3) Dump the container, refill with water and add muriatic acid to the water so that you have a 10:1 water: acid mixture and soak the grids for another 3 hours, this will clean any calcium off of the grids. Rinse grids again and reinstall them in the filter.
4) Now, run pump and bleed off the air from the filter and add 100% of the DE the filter calls for.


I Hope that this is enough for most DE filter owners; if you have any questions, we’ll be here to answer them!

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That's about the best I could come up with, having only 5 months to work on it

If any of you see any mistakes, wrong info, omissions or places where I'm less than lucid - please point them out so I can edit this and make it look like I used my 5 months well

very well written

Most excellent Ted! This thread has been added to The Stickies page!

was wondering, does anyone have a "calculator" to determine the amount of DE required for each size? i have one of the blue scoopies, and a 60 sq ft filter. i was told 10 cups, but that seems like a lot. any calculator?

For hayward grid filters simply divide the filter's area in sq feet by 8 to get the # of lbs DE to add when filter is fully clean. For the bump filters it's not as linear (but is still very easy). All the models start "EC-'X''Y' (ie EC-50 - X=5, Y=0), use X as the # of lbs DE to add to a fully clean unit.

(* Other manufacturers have the owners add an extra 1/2 lb for clean start up - I don't know why there's a difference but 1/2 lb of DE isn't much - the only place it could potentially become problematic is on the very small filters) If you know the manufacturer, you should be able to go on line and pull the owner's manual for your unit - if not, going with the numbers I just gave and following the instructions in the sticky should prevent any performance problems.

Ike, if the blue scoop you have is 3/4 lb 10 scoops matches what I said above perfectly!

Waste is Da Man! Good stuff! Good stuff!

i think THAT needs to be added to the sticky. it is very difficult to get a definite answer on this subject. like i said, one place told me 11 lbs while another told me 11 coffee cans (and one 1lb coffee can only holds 1/2 lb DE as waste stated).

Ike, I didn't include this in my post (which became a sticky) because it's a little bit more 'advanced' than the basics. You've asked the question, and had it answered, so this info is there for folks who may need it. I'm very happy!! to have been able to help you, and anyone else with a similar concern.

As I see it, unless a sticky claims to go into all the details, stickies should be about the 'basics' of whichever topic they concern- when there are more specific questions the poster, or other members with knowledge on the given topic will 'fill in the gaps' (as has happened here) - I see a sticky as a quick, and simple guide to the subject at hand - the specifics/ or 'full story' can be found within the forum, or by asking for them - as you have (I could have gone into detailed instructions about which size wrench to use for breaking one apart and how to reassemble a grid filter, but thought I'd wait until the question became relevant for one of the members, but if enough folks wanted the info - I'd ask Sean to make it a sticky )

(If Sean B feels that this would further my sticky - he can, if he wants, incorporate the quote you gave to be a part of the sticky)

I sincerely hope that you have a 'trouble free pool' all this season!!

At the bottom of the sticky is a link back to this thread so anyone who wants more information on the topic can follow the link.

^me ^waste

Waste,

I don't know if I got a question through to you earlier concerning the controller on a Hayward D.E.7220. You mentioned you were familiar with the Hayward. My controller is only four positions: Filter, Backwash, Waste and Pool/Spa Boost. Any suggestions about what to do when you say rinse in your D.E. backwashing procedure/instructions if I don't have this position?


Thanks.


Thomas

When doing the acid soak:

Is it ok to literally submerge the entire assy, or should only the fingers be submerged?

I don't have a container that I can stand mine up in, but I do have one that I could lay it on it's side in to soak. I'm specifically concerned about the rubber gasket at the top of the fingers.

If you don't have rinse then you skip the rise step. Some DE might get into the pool but there really isn't anything you can do about that.

Jason,

Thanks for the info re: Hayward no rinse.

Best,


Thomas

Hey There, I posted my own topic "Hayward Perflex Pressure Issues". Any chance you could take a look at it and comment... Desperate for some answers... Thanx so much

1- When doing the acid soak: Is it ok to literally submerge the entire assy, or should only the fingers be submerged? I'm specifically concerned about the rubber gaskets, metal screws etc .

2- Anybody have any suggestions for a container to do all this in? Pretty big barrel, where do you get one?

3- No worries re “Fiber Clear”?
“Replaces DE, the Safe alternative, biodegradable bla bla…”
This Fiber Clear says my 48SF filter requires only 12 cups (vs. the 6lbs of DE per Waste’s post above). 12 cups of this stuff is nowhere near 6 lb. because I am looking at a 3 lb bag & it looks about like it contains 20 cups.

Thanks

Johnny, I'm happy to see that you are following through on reading the older posts and responding to them

I can answer the first 2 questions, but will leave the DE substitute to Evan (waterbear) or others, since I've never played with it.

#1 - As long as the acid is dilute and you don't leave them in too long, the short exposure to the acid mixture won't wreck the metal parts. Of course, any acid exposure will start to 'eat' metal, but the short dip in the dilution I recommended shouldn't cause undue wear on the metal parts. I believe you have grids, not fingers, so you can disassemble the grid unit and only soak the grids if you'd like - folks with finger/ bump filters can soak the fingers to ~1/2" below the metal parts to protect them.

#2 - We use 40 gallon trash barrels to do the acid washes, some of the larger grid assemblies need to be turned over for another 3 hours to completely clean the grids (ie. they are so big they stick up out of the soak). Another choice, for those with grid assemblies is to take the grids out of the assembly and use a plastic storage bin (rectangular), this is probably less wasteful of water and acid.

I assume you plan on your own acid wash - PLEASE remember to do the degreasing prewash!


Also -- since I wrote the stickie, I've come to realize that the folks who come here for this info are willing to do the best things for their pools. As such, I now recommend to the folks here that they do the manual hosing of the grids/ fingers, rather than the backwash or 'bump and dump'! (However, if you're pressed for time, those are still very viable, as long as you remember to only add the 80% of the DE)

Thanks again for joining us here, Johnny! It's refreshing to have some the older questions/ threads revisited and refreshed with some new questions

Great post!

I was urgently looking around on recommendations on how to give maintenance to a DE Filter because the pool labeled "CL" on my signature, which has a Pentair Grid DE Filter Plus, model FNS 48, suddenly after it was used last weekend by some guests, has now a low flow/circulation problem.

Will follow every step on the releasing the air, checking the PSI before-after and check if there is any improvement.

I was looking for video guides on how to do this, but couldn't find ANY on the pentair DE filter, just cardtridge filters.

Also found the manual which is detailed on how to do this, though some pictures would have been nice on it.
http://www.pentairpool.com/es/pdfs/FNSPlusOM.pdf

Will combine waste's post with the manual and other link I got (http://www.ehow.com/how_5124900_clean-f ... lters.html) to do this.

First will do the normal "cleaning", replacing DE. If the pressure or flow is not good, then will try the manual/opening the filter steps.

Thanks waste, great post!

hello all, D.E filters are great we have a 12,500 gal, softswim AG pool with a hayward ec-50c and a 1 1/2 hp hayward power flo and it cleared a green ugly pool up in 12 hours. thank you to whoever created D.E filters. P.S i added no shock or chemicals to the pool for 48 hours.

Not quite the way I'd have done it, but if it worked for you (I believe in both good chemistry and good filtering )