Adding DE to clean filter

Apr 11, 2017
4
Fullerton, CA
#1
Hello!

Somehow I know for a fact my question has been answered, possibly many times, however a search does not really answer it...mostly an opinion here or there, but no real hard answer. I am ready to call the DE company. But before that, I will ask you.

I purchased a house with a pool last December. My first pool that I own (and am now responsible for).

I initially kept the pool guy the previous owner had and learned from him how he does things. That, coupled with this site, has led me to send him on his way and do things myself, changing a couple of things. Being winter, we were not using the pool anyway, so playing with the chemistry and goofing up were not going to spoil the weekend fun. Now it's warming up....

So anyway, a quick rundown of my pool and the things I did before going into my DE question.

Approx. 18X40 foot rectangle pool 4 foot deep level for about 1/2 of the length, then slowly drop to 6 foot deep at max last 5 feet or so (not deep). A couple of waterfall features and spa in the corner of the shallow end.

The pool guy would come weekly and vacuum it out and clean the skimmer and filter baskets and check chemistry. He told me very sternly not to go to pool supply houses as they will take an out of spec reading and sell me something which would probably only temporarily fix the issue and maybe cause others. He said that if anything, other than chlorine is out of normal range, to not panic and simply wait until the next week and see if it is holding or trending in one way or another. Most likely, the KH will remain somewhat stable and pH may fluctuate depending on use and whatnot, but would also average over the month to a specific number, only adjust to the average number, not the weekly number.

For chlorine, he added pucks to a floater (my pool has a SWG, but it is disconnected and he said something about years ago it didn't work so they just disconnected it. I knew this before buying the property). He would add one or two pucks per week depending on what he measured. Keep in mind the pool is not being used (by humans, I did see ducks in it) during this time.

So anyway, after reading this site, I checked the CYA and it is quite high (over 150), so I blame the pucks and have switched to bleach from Costco. Testing daily for the first month, I have found I can keep ppm stable around 4ppm if I add 1 quart each morning. This is based on 4 people using the pool about 4 hours a week (this will increase as summer comes along I am sure). I also added an automatic floor vacuum and floating skimmer. The pool is basically always clean now except after a very windy day. KH, pH have been very stable, as the pool guy told me. I have not done anything in four months to change these parameters.

So anyway there I am. Now I have a DE filter (grid style) in need of cleaning. I did it myself!!! Yay, me! But what I didn't expect is how difficult it is to figure out how much DE to add.

Some people say pounds, some say cans, some say cups. Man. Based on my filter size (which is a unit of surface area), the box of DE that I have (which is 1/2 full from previous owners) say to add 7 "1 pound coffee cans" to the skimmer.

OK, fine, but according to this site, DE is 1/2 as dense as coffee, so do I use an actual coffee can? If so, that means 7 x 1/2 lb or 3.5 pounds of DE...is this correct? Or 7 pounds (14 cans)? The stupid box does not say how many actual pounds of DE to add (or cups). So I went ahead and simply got an old 1 pound coffee can and added 7 of those. Is this overkill? Under-kill? I have no idea. I am thinking of waiting a month and cleaning the filter again just to see how well it was coated.

Why can this not be easily explained? All they need to do is say how much volume to add or even weight, not an abstract number using another arbitrary item for comparison, especially when that item is not comparable....7 cups, fine, I get it. 7 pounds, fine I get it. 7 1b coffee cans... Certainly they must know a can is a unit of volume....what does coffee have to do with it anyway? Who else uses this as actual language? I can only think this is terminology passed down over many decades from the first person to use DE and they happened to use a coffee can and it somehow stuck.

I just bought 3 cups of girl scout cookies...they charge $5 per box. How much do I owe them? It's just NOT PRACTICAL units of measurement!

Is there an actual item that is a scoop or something that is equivalent in DE to a 1 pound coffee can? If so, please show me and I will buy it and know to just add 7 of those.

I should have kept the pool guy around long enough to change the filter and see how much he added.....

Thanks in advance for any insight you can give me. Everything else about the pool is wonderful (though I want to put a controller on it that I can run from my phone to switch to spa mode, temp, etc., that would be great)
 

Sammy2

Well-known member
Aug 30, 2016
378
Riverside, CA
#4
It should say the quantity of DE required on the side of the filter. If it doesn't find the manufacturer and model number then look it up. If they said to add 7 1 pound coffee cans then they mean to say 3½ pounds. This sounds to be a filter maybe about 30 Square Feet or so?
 

kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
36,828
Tallahassee, FL
#5
And TFP scores again! Love it!

I just wanted to say I love your writing style! I can SO feel your pain!

Is there anything else we can help you with? We LOVE to help!

Kim:kim:
 
OP
OP
E
Apr 11, 2017
4
Fullerton, CA
#7
Jimrahbe, was that a crack at my long-windedness in getting to the point? Well, I'll have you know that back in the early 80's......

Leebo, thanks!

$9 for a plastic scoop? Are they nuts? Well, I guess you pay for the magic conversion factor. I will get one. It says 1 lb scoop, so I imagine it is twice the volume of a coffee can.

Sammy2, there is a label on the filter saying 60 sqft. However, I just now checked it more closely and I saw another label covered in old dirt. As I cleaned it off I saw a small table that actually says for every 10sqft to add 1 lb of DE....this is on the filter itself, not the DE box, so I trust it more. This means I should add 6 lbs, and I only added 7 cans, so I am about 1/2 of what I need.

Now the question is, since I have had the thing running for a week, is it too late to add more? Should I break it down and clean it again? Or should I just expect the pressure to rise faster than it should and clean it at that point?

Kimkats, thanks! I wish you were my HS English teacher, she gave me a C.

Nursenini, thanks! Glad to help. I am always known for bringing up the awkward topics when in a group.
 

pooldv

Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
Aug 10, 2012
25,006
DFW, TX
#8
Welcome to TFP!

How about running over to the grocery store and buying a pound of coffee? It comes with a free DE scoop. :)
 

Sammy2

Well-known member
Aug 30, 2016
378
Riverside, CA
#10
This is what I would do..

Open up the filter and make sure all the grids are coated with some DE.

If yes, add more DE.

If no, clean the grids again and then add the right amout of DE or at least backwash the system and then add more DE.

I'm no expert but to me this seems to be what to do from a practicality standpoint.

Sent from my SM-G930P using Tapatalk
 

Sammy2

Well-known member
Aug 30, 2016
378
Riverside, CA
#12
The thing is that the density of DE is half that of coffee so 2 true 1lb cans (not the rip off 13 oz cans common today) will give you 1 lb of DE so you can just use that. You get the measure you need and a pound of free coffee.

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OP
OP
E
Apr 11, 2017
4
Fullerton, CA
#13
When I asked the question I didn't know, but now I know that when the directions say to add "7 1lb coffee cans" of DE, that I should have scooped out 14 coffee cans filled with DE. The directions were not clear. Thankfully last night I found another label on the filter itself that I should have looked for earlier (granted this label is facing the wall and hard to see) that says to add 6 lbs of DE, which is straightforward and would be 12 cans full. I only added 7 cans full because that is how I interpreted it. I am going to go ahead and add 5 more cans this weekend just to be safe, even though the filter has been running and I may be wasting my DE.