Slow loss of flow at returns

[cfuser]

Hi all...

I recently purchased and Intelliflo 810 and had it professionally installed (it is connected to a Hayward DE Filter). When first starting up and running at 2350 RPM, the pressure at the returns is great. After a few days, it is barely a trickle. I've cleaned the grids numerous times and that seems to help for a while, but I still see the same issue. If I backwash just for about 10 seconds and then filter as normal, the returns have pressure again. I've run a day or so without the grids and the flow seemed to hold, but I didn't go over multiple days. The pressure at the filter looks good typically, between about 9ish to 15ish over the course of a few days.

I'm trying to decide whether it's an issue with the filtration or the pump installation--I have never had this issue before this pump was installed, but I can't prove it was due to that or just a coincidence and I'd prefer to to have the installer come back out unless I have something tangible or have at least exhausted all my options. Is there anything else I can do to troubleshoot? Am I missing something obvious?

Thanks.

 

[duraleigh]

Welcome to the forum. About a 95% chance that you have a water chemistry issue......not filtration. Your filter is doing exactly what it is supposed to de.....filter debris from your water.

We see posts virtually identical to this and it most always is water chemistry. Can you post current test results? What does your water look like?

 

[pooldv]

Welcome to TFP!

I would bet that there is algae starting to grow in the pool due to chlorine dropping below the minimum level at some point, Chlorine CYA Chart. Once it gets a start it just keeps growing until you SLAM - Shock Level And Maintain the pool to kill the algae.

 

[cfuser]

Thanks for the super speedy responses. I've frequented my pool store and had them take measurements for my water. My phosphates are high, pH 7.8, CYA about 69, TC .5, FC 0 (I've since shocked and, based upon the recommendation of the store, Banish and Starve). The water is clear with a slight yellow algae that I brushed off this AM.

I'm all in favor of doing this, but for the most part, I believe the chemistry has mostly been OK. Chicken and the egg maybe?; pool doesn't move the water like it should, algae increases or vice versa?

Correlation is not causation, but I didn't notice this issue before the pump install. Perhaps the new pump is just bringing to light an existing issue--I'm not sure, but I '*am* trying to ensure that there is nothing wrong w/ the install before the warranty on it expires.

Two other items of note that may or may not help: first, I noticed a leak in my backwash pipe (off a spider valve) such that, when I backwash, was sprays in a thin stream. Next, some grids have been replaced, some are older. The latest suggestion from the store was to replace the older grids.

Thanks all.

 

[pooldv]

You only care about phosphate if you are trying to feed some algae. TFP prefers not to let it grow in the first place thus making phosphate irrelevant. The only thing that stops algae from growing is proper maintenance of the chlorine level relative to your CYA level. The only thing that allows algae to grow is insufficient chlorine in the pool relative to the CYA level. Also, it is worth noting that if there is low enough chlorine level to allow algae to grow then the pool is also unsanitary enough to allow person to person disease, virus and/or bacteria transmission. Chlorine CYA Chart Chlorine should always be at target level for your CYA and never be allowed to drop below minimum.

More here, Pool School - ABCs of Pool Water Chemistry and here, Pool School - How to Chlorinate Your Pool

 

[duraleigh]

Blending pool store testing and advice with what we say never works. It's your call but you must choose between the two or you end up in the befuddled middle.

I know you are focused on your pump but I will bet that your water chemistry is at fault. I have no idea what Banish and Starve are but I doubt they will fix your pool. They are Pool Store "magic Bullets" that are incredibly poor substitutes for testing and understanding your pool.

If you choose to use TFP, read "The ABC's of Pool Water Chemistry" up in Pool School. That'll get you started and we'll help with questions along the way.

 

[OldPoolMan]

How big is your de filter? I recently did a repair call to a guy with a smaller de filter and had recently gotten a VSP. After a short run, his suction began to decrease because it could not handle the flow. It was not big enough and his grids were old.

 

[kimkats]

Being able to sweep off the yellow dust tells me that you are about to have a major problem.

You filter is doing it's job and trying to filter that mess out of your water. You HAVE to get your FC up and get your own test kit so you can take care of your pool every day.

Kim