Is pressure on DE too low?

Tapioca1518

New member
Mar 6, 2024
4
Central Valley CA
First time pool owner taking over maintenance after back-to-back frustrations with services. Appreciate any insights or links to posts (haven't found any exact matches and I don't understand equipment differences enough to extrapolate).

Short question: after adding 100% of recommended DE for 48 sq ft grid (32 oz scoop, 9 scoops dissolved and poured into skimmer while pump running normally), the PSI is quite low at ~5 PSI after charging. I don't know what the baseline should be at either prime (3400rpm) or various variable speeds, and I cannot find original manual.

As a reference, the PSI was running at 10-15 PSI, but checking the grid, it was extremely gunky (see photo). I fully cleaned the grids and debris in bottom of chamber prior to charging. My guess is that this is 1) some leftover algae from last fall and/or 2) prior pool servicer overloaded the DE or used wrong DE.

1) Am I undercharged?

2) Is there some chance someone retro'ed a 60 sq ft grid into my 48 sq ft chamber?

3) what's a good program to set for my 3 stages?
 

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1518,

At what speed were you getting 10 to 15 lbs???

What speed are you getting 5 PSI?

I think your filter takes 9 Lbs. of DE material.. How much does one of your 'scoops' weigh??

In my experience, there is not very much difference in the PSI without the DE, and the PSI with clean DE.

The cleaner the filter the less the PSI will be.

Thanks,

Jim R.
 
Thanks Jim -- It was 10-15 PSI at 2900 rpm, I think (could have been 2000rpm). Getting 4 PSI at 2900 rpm now.

My 32 oz scoop is is right at 0.5 lbs, so 9 scoops = 4.5 pounds. 4.5 lbs is what 48 sq ft grid calls for on DE package. Where did you get 9 pound figure?
 
1518,

My DE box calls for 7.5 lbs for a 50 Sq.Ft. Filter

Sorry, I just 'assumed' it was 9 lbs... because you said 9 scoops and my scoops are 1 lb.. :(

Clean DE does not add very much resistance to the flow of water.

If the filter was running 10 - 15 lbs dirty, then 4 or 5 lbs sounds ok to me.

I am not sure there is an issue at all, but it could be that the port that sends water to the filter gauge is plugged and causing the gauge to read incorrectly.

If this were my system, I'd use it as is and see what happens at the next cleaning.

I assume that you have plenty of flow when you feel the water coming out of your pool returns.

Thanks,

Jim R.
 
Roger -- makes sense. Appreciate your input Jim.

I found the Titan RPM manual (not quite same model, but close?) calling for 4.8 pounds for 48 sq ft -- https://www.poolinspections.com/manuals/filters/de_titan_filter.pdf

I can see how it goes without adding more DE then. For next time I clean, the photos above look really caked/gunky. Is that expected? I have seen some posts suggest it's normal/typical and others where they say the DE should not stick.
 
Where are the wingnuts that go on the threads?

Maybe the Push/Pull/Slide Valve is defective.

Add 1 pound of DE through the skimmer and watch the returns to see if they remain clear or if a bunch of DE shoots out in a minute or 2.

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Good eye! I took off the wingnuts prior to photos, so no concern there.

I watched the returns/outlets while charging initially over ~10 minutes, and water stayed totally clear. The watch glass in front of pump did cloud up and then clear, which I think is what's expected (skimmer and main drain join together and continue into the pump via chamber with a watchglass on it)
 
Back before someone decided to market DE scoops that are a standard "1 pound" size, DE was measured using 1lb coffee cans. One 1 lb coffee can of DE eventually came to be called 1 lb of DE. The correct way to measure it is to buy a DE scoop, which will give the correct volume of DE with 1 scoop = the same as a 1 pound coffee can. If for some reason you do use too much DE, it will just shorten the cleaning cycle on the filter and you can clean it and recharge the filter with the proper amount.
You asked if DE was supposed to cake on the grids or fall off. The answer is yes. When the filter is clean the DE will coat the grids and fall off when the pump is not running. As the dirt load in the filter rises the combination of dirt and DE will stick to the grids and the filter pressure will rise. When the pressure is 20-25% higher than it was when it was first cleaned it is time to clean the filter again.
 
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