DE filter requiring constant backwashing

[Saturn94]

Originally, one scoop of DE was measured using a 1 lb coffee can. DE scoops were developed that held the same amount of DE as a 1 pound can. Then the 1lb coffee can became history, the only size close is 10-12 ounces.

So the question is, when the Hayward says add 6 pounds of DE, do you just add 6 scoops of DE? Or do you actually need to add 6 pounds of DE (which seems like a lot!)?

 

[zea3]

Six DE scoops.

 

[Saturn94]

Six DE scoops.

Good. That’s what I’ve been doing all these years (7.5 scoops for my Hayward 6020 filter).

 

[IUsedToSail]

Thanks. So the pool shop salt measurement is not reliable? I believe they use BioGuard ALEX for their testing.

HAha... I just went through this in another thread. My local store here in MD also uses the BioGuard Alex system. I had them run a test last week, their numbers were pretty close to my at home test, however their recommended ranges were noticeably askew and of course their solutions were very product heavy...

I was in a similar situation as you last year - back wash the filter, add DE, all is good for 10 days and then I would get a significant bubble. I cleaned the grids really well towards end of the season and it got a better but I still wasn't getting that 4-5 weeks between back washes everyone else seems to experience. Anyway, I bought a set of new cheap grids for $85 on Amazon over the Winter. I opened the pool with the old grids and after it was completely clear I broke down and the filter and was going to clean the old grids and choose a few to keep as backups. When I compared the new grids to the old ones I was really surprised at how much calcium build up was on them, I also discovered previously unnoticed many broken fins inside the old grids which probably allowed them to collapse under suction reducing flow. Anyway, with the new grids in place, I'm now three weeks since a backwash with no real noticeable difference in flow and the bubble hasn't been an issue.

 

[Saturn94]

Any idea what the actual volume of this orange scoop is? My "Blue Devil" 1lb scoop holds about 1 liter of water.

Interestingly, I just talked to Hayward's support line, and they told me the 6lbs in the manual was actual weight of DE, and not volume. They didn't seem to know anything about DE scoops though, so I'm not confident in their answer.

Interesting….I just looked at what it says on my scoop (I’ve never paid attention to it before). It’s a Hayward scoop (I assume it came with the filter) and says it’s 1# of DE when filled level with the top. I’ve never weighed it, but I remember thinking before it didn’t feel like a pound when filled with DE.

Btw, I just checked and it holds about 50oz of water (about 1.5 liters).

 

[bjohannes]

Interesting….I just looked at what it says on my scoop (I’ve never paid attention to it before). It’s a Hayward scoop (I assume it came with the filter) and says it’s 1# of DE when filled level with the top. I’ve never weighed it, but I remember thinking before it didn’t feel like a pound when filled with DE.

Btw, I just checked and it holds about 50oz of water (about 1.5 liters).

Interesting. That orange scoop seems to be 50% more volume than my blue devil scoop. If that's the case, then I should be adding 9 scoops (about 1 scoop per 5 sqft of filter area, just like it says on the bottom).

 

[Saturn94]

Interesting. That orange scoop seems to be 50% more volume than my blue devil scoop. If that's the case, then I should be adding 9 scoops (about 1 scoop per 5 sqft of filter area, just like it says on the bottom).

If you like, I can physically measure the dimensions of my scoop for you to compare.

 

[bjohannes]

If you like, I can physically measure the dimensions of my scoop for you to compare.

That'd be great, thanks!

 

[Saturn94]

That'd be great, thanks!

Outside measurements:

Top Diameter: 5 inches (127mm)
Bottom Diameter: 4 inches (101.6mm)
Height: 6.125 inches (155.58mm)

Hope this is helpful.

 

[bjohannes]

I've now been running on the same DE powder (9.5 of my blue scoops) for 4 weeks with no signs of backwashing needed yet. Running a higher FC (no lower than 4.5) made all the difference.