Adding D.E. After cleaning

[Raiken3712]

So this is our first time with a D.E. filter, and I think we put everything back together correctly.

The thing is when we turned it on to see if anything was leaking and it was running right the pressure was going from 7-10 and back to 7. Is this normal behavior for the filter guage until you add in the D.E.?

 

[jblizzle]

I never run it long enough to notice before adding DE ... but it seems odd that you would see fluctuations.

 

[Raiken3712]

I never run it long enough to notice before adding DE ... but it seems odd that you would see fluctuations.

I guess we'll add the DE and see what happens. So could you explain how to add DE real quick just to make sure I'm clear on doing it correctly.

Thanks

 

[jblizzle]

I measure out the correct weight in a bucket. Then fill the bucket with water and mix it up with my arm until it is all in a slurry (this is actually more difficult than you would think it would be). Then I flip on the pump and slowly pour it into the skimmer (with no basket or diverter in the skimmer).

 

[harleysilo]

I do what jblizzle does as well, you can read in debth about it use-and-care-for-de-filters-t4086.html

 

[Raiken3712]

Cleaned it reassembled and added 6 pounds DE per instructions in the filter manual and the pressure started at 15. I'm so confused.....I figured doing a manual cleaning would remove whatever was causing the pressure to be above the clean pressure on start of 10

 

[jblizzle]

Well appears your clean pressure is 15 and not 10.

Posted from my Droid with Tapatalk ... sorry if my response is short

 

[Raiken3712]

Well appears your clean pressure is 15 and not 10.

Posted from my Droid with Tapatalk ... sorry if my response is short

Why would the clean pressure be 15 now when before it was 10? That seems like quite a bit. I guess as long as it actually works right at a higher pressure its fine...haven't had a chance to see if its working right so maybe its fine.

Just heard about the 15, and figured it would be back to the 10 it started at originally after cleaning everything.

 

[jblizzle]

I am confused. It ran at 10 then you added DE and now it is 15, right? Did it used to run at 10 with DE?

If so, are all the valves the same? I can make my pressure change all over depending on what suction and return line combination I have open.

Posted from my Droid with Tapatalk ... sorry if my response is short

 

[Raiken3712]

It ran at 10 when the guy first installed and added fresh DE. I figured after cleaning the grids manually and adding DE it would be back to 10.

We backwashed a few times without adding DE because we didn't have any at the time. Each time the pressure went back to 10. After about four backwashes the pressure started at 15. I decided since we hadn't been adding DE and we didn't know how much was in it anymore that it might be a good idea to manually clean and add new.

So we did and the pressure is still at 15. This is with valve set 75% suction 25% skimmer. No main drain. Valve was set the same way before.

 

[jblizzle]

What all did you do for the manual cleaning? Pressure wash, soap soak, and acid soak?

 

[Raiken3712]

What all did you do for the manual cleaning? Pressure wash, soap soak, and acid soak?

Pressure wash is all. Its been less than a week and the grids didn't look like they had build up. I can't imagine there would be any kind of buildup in less than a week. They were just plain white after I cleaned them. No chalky texture.

 

[jblizzle]

Confused again. So the guy first installed only a week ago? And you have backwashed how many times? why?

 

[Raiken3712]

The pressure went up to clean pressure that many times. The cleaner we are using would stop working and the return jets weren't putting out all that much pressure. So we backwashed it. I was under the impression that if the pressure stayed up it needed a manual cleaning.

I backwashed again because it was 7-10 higher than the clean pressure again and got it back down to a clean pressure of 10. Right now I figure maybe my brother didn't backwash long enough last time and so that's why it was higher.

Someone told me floc really gums up the filter so perhaps that is the problem. We flocced before we got this filter and there is quite a bit of stuff to clean. Its clearing the pool albeit slowly.

I wouldn't figure on backwashing that many times either.

I don't know I've never had a pool before...it seems to be working though. It is clearing the pool its just taking awhile. I know in general it takes a month between backwashes...the only thing I can figure is its just the amount of junk in the pool causing it to require more cleaning.

Perhaps the not adding DE after backwashing contributed to the problem or maybe adding too much at the start though I've seen several recommendations for 12 scoops for that size DE filter so 9 that he added first wouldn't be too high.

When I manually cleaned it there was some DE clumped at the bottom of the tank so perhaps he added too much or just too much too fast leading to needing to clean it more...I'm not sure.

You could see all the way to the bottom a short while ago. There is quite a bit of dirt or dirt looking stuff on the bottom. Probably a combination of dirt/dead algae etc...

 

[jblizzle]

There is no "general monthly backwashing". You should backwash when the pressure goes up 20-25% over your clean pressure. Assuming it is clean at 15, then you should backwash by 19psi.

You said he added 9 lbs ... now you say scoops. You would be much better off weighing the DE for yourself since the amount of DE in a "scoop" if very variable depending on how well it is packed.

It is pretty normal to find DE packed between the grids and on the bottom, even after a backwash. Which is why we say to add 80% if you do not do a full cleaning.

 

[Raiken3712]

There is no "general monthly backwashing". You should backwash when the pressure goes up 20-25% over your clean pressure. Assuming it is clean at 15, then you should backwash by 19psi.

You said he added 9 lbs ... now you say scoops. You would be much better off weighing the DE for yourself since the amount of DE in a "scoop" if very variable depending on how well it is packed.

It is pretty normal to find DE packed between the grids and on the bottom, even after a backwash. Which is why we say to add 80% if you do not do a full cleaning.

Well he didn't weight it out. He said he was adding 9 pounds. It was 9 scoops worth. If it wasn't packed well it could have been less. If clumping at the bottom is normal than he probably didn't add too much just thinking of possible reasons why its requiring more cleaning.

I've seen that 20-25% number before...been doing at 7-10 psi, but don't know the difference. I can't remember the reasons listed for doing it sooner. He said generally you would clean once a month.

I guess he means with a clean pool it would be about once a month. A dirtier pool would mean shorter clean cycles obviously, but I suppose there could be a problem causing it to need to be backwashed more frequently. Everything in the filter seems to be fine though from what I saw.

The DE scoops are supposed to be 1 pound. I haven't been weighing them, but I shake it back and forth so it settles in the scoop. I figured that would be good enough. I guess I could do that and weight it to see if that is accurate.

 

[jblizzle]

You might be surprised if you actually weighed them ... Best I could get with an official 1 lb DE scoop, was ~14.5 oz ... 0.9 lbs

If you let the pressure go up much more than 25%, then the flow is reduced too much and the filtering is less effective.

If you have a clean pool and the correct filter, you may be able to go many months between backwashing. I think I just went about 6 months on mine, then backwashed for the heck of it even though the pressure had not gone up 25%.

 

[Raiken3712]

You might be surprised if you actually weighed them ... Best I could get with an official 1 lb DE scoop, was ~14.5 oz ... 0.9 lbs

If you let the pressure go up much more than 25%, then the flow is reduced too much and the filtering is less effective.

If you have a clean pool and the correct filter, you may be able to go many months between backwashing. I think I just went about 6 months on mine, then backwashed for the heck of it even though the pressure had not gone up 25%.

Makes sense. Doing 7-10 like we were had the returns with barely any pressure and the suction was much less too. Therefore the filtering capacity would be quite a bit less.

I wonder how they came up with the 7-10 psi amount. My clean pressure is 9 so 25% is 11.25. I weighed the scoop and it was 15.95 ounces. That was with the scoop and the DE. I'm not sure what the scoop weighs, but I could do that later and figure it out. My measuring method seems to end up pretty close to a pound. Should I worry about a few tenths of a pound?

 

[jblizzle]

You should kind of worry since after ~9 scoops you could be off by a full pound if each is off by 1/10.

The 7-10psi is just an old recommendation that does not make much sense. +10psi on a filter starting at 5psi (+200%) is a lot different than +10psi on a filter that starts at 20psi (+50%).

The 20-25% recommendation is based on "experiments" done by forum experts. But using a % recommendation makes it applicable to any starting pressure.

Why are you now saying your clean pressure is 9psi? I thought it was 15psi just after you added the DE?

 

[Raiken3712]

You should kind of worry since after ~9 scoops you could be off by a full pound if each is off by 1/10.

The 7-10psi is just an old recommendation that does not make much sense. +10psi on a filter starting at 5psi (+200%) is a lot different than +10psi on a filter that starts at 20psi (+50%).

The 20-25% recommendation is based on "experiments" done by forum experts. But using a % recommendation makes it applicable to any starting pressure.

Why are you now saying your clean pressure is 9psi? I thought it was 15psi just after you added the DE?

Well the filter recommendation is 6 pounds so I guess I would still be off by a decent amount. You have a point.

15 was what the starting clean pressure was after my brother backwashed. I backwashed it again and it was down to 9 again. I think he just didn't backwash it long enough or at least that makes sense to me.

Its clearing the water slowly but surely so I think its working fine...its just taking awhile because we had 4-6 Algae blooms. We had it open during winter without adding much of anything.

We did shock a few times but obviously didn't do enough with it.

The built up dead algae is just taking awhile to clean. Its definitely working though as I can see the bottom now.

I think we'll stay more on top of it next time because it probably would have been much less work if we had done more during the winter. It probably wouldn't be clear right now because that cartridge filters elements were all bad, but it wouldn't have been as bad.